QR Tequilo VS. MultiSport 4000
Johny Ringo
detailed spec sheet and plan to have them price one with 100% DA parts. The
Cannondale is 100 Dura Ace stock. The QR frames are less, but the
workmanship seems less than the MS. QR's web site really doesn't have specs.
Does anyone have an opinion as to the value element between these two
choices, assuming the components were identical? I have a Trek road bike now
so I don't have experience with either bikes, or bikes in general for that
matter.
Rance Mcclain
Rick Denney wrote:
> (snip)
>
> The 'dale's seat tube is not as steep. I think it's 76 degrees,
> instead of the 78 used by QR.
>
Actually, the seattube angle on the new Cannondale MS4000 is 78 degree until you
get to a 56cm frame size, when it backs off to a 77 degree angle. These specs
were given to me by C-dale when I was shopping around for a new bike.
> The "blend" refers to a few changes in the parts mix that are made of
> necessity for cost or configuration reasons. In particular, Dura Ace
> chainrings do not come in the larger sizes that QR uses to offset the
> effect of smaller wheels. The Stronglight crank that they use is the
> top of Stronglight's line, but it is not as nice as a Dura Ace. It
> can, however, be ordered with 42/56 chainrings. If you want a bike
> with 100% Dura Ace, but still uses small wheels, then you'll have to
> use an 11-toth cog in the back to offset the standard-size chainrings
> in the front. This is actually not a bad solution. But QR could not
> hit their price point with that mix.
I bought my wife a C-dale MS4000 frame/fork, and built it up with an
Ultegra(drivetrain) &Dia-compe(brakeset/levers) blend that is working out great.
The component package is very similar to the spec'd equipment on the MS2000.
>
>
> I agree that the QR frames are not as pretty in their construction
> details as a Cannondale. But they are well enough made for all of
> that, and they are a very good value. There's a reason why many
> triathletes that are not fleet-owning bikies like me bought enough
> QR's to make them the leader in that sector.
>
> But there are other frames available in that price range that adopt
> the forward position, and can be speced with whatever parts you
> desire.
>
> Rick "I won't mention any one in particular" Denney
>
> [subliminal afterthought: Habanero]
Dan Empfield
<E2EEECC3EF0660C0.F5F8AB8C...@library-proxy.airnews.net>,
r...@odetics.com wrote:
> The "blend" refers to a few changes in the parts mix that are made of
> necessity for cost or configuration reasons. In particular, Dura Ace
> chainrings do not come in the larger sizes that QR uses to offset the
> effect of smaller wheels. The Stronglight crank that they use is the
> top of Stronglight's line, but it is not as nice as a Dura Ace.
i'd like to take exception to a couple of things you say here. first
about the stronglight. i chose this crank because the medial side of each
crankarm on either new dura ace or ultegra sticks out just over 1 cm from
the frame vs stronglight's speedlight crank (or, for that matter, dura ace
from the previous, non-tubular iteration). that's more than 2cm in total
distance. i find new dura ace hard to ride if you like float in your
cleats, as i kept banging my heels and maleoli on the crank. we've spec'd
a lot of dura ace in our time and have no problem doing so now, when it's
the right part. when it's not, we won't.
> I agree that the QR frames are not as pretty in their construction
> details as a Cannondale.
this one hurts. i don't know, but i think the original writer may be
describing the difference between smooth vs beaded welds, or maybe a
formed downtube (most rst'ers know my view on that). maybe it's just
personal preference, but i can't imagine a tequilo being considered the
cosmetic inferior of the c'dale in attention to detail. but whatever
floats your boat.
re the chainrings, we ourselves make a 55t pinned chainring for 9sp, we
start with a stronglight and modify it ourselves. but we also use 11t 1st
position. most of the time i prefer 53x11, only the baddest of the bad
can reasonably handle 55x11. but that's what we put on the bike standard,
we assume you're jurgen zack or spencer smith when you get the bike, if
you're not then you've got to tone it down yourself if you want. so the
choice of stronglight has nothing to do with the chainring sizes.
qrman
Rick Denney
wrote:
The 'dale's seat tube is not as steep. I think it's 76 degrees,
instead of the 78 used by QR.
The "blend" refers to a few changes in the parts mix that are made of
necessity for cost or configuration reasons. In particular, Dura Ace
chainrings do not come in the larger sizes that QR uses to offset the
effect of smaller wheels. The Stronglight crank that they use is the
top of Stronglight's line, but it is not as nice as a Dura Ace. It
can, however, be ordered with 42/56 chainrings. If you want a bike
with 100% Dura Ace, but still uses small wheels, then you'll have to
use an 11-toth cog in the back to offset the standard-size chainrings
in the front. This is actually not a bad solution. But QR could not
hit their price point with that mix.
I agree that the QR frames are not as pretty in their construction
PPWrench
Which LBS provides the best service?(assuming you aren't a MO cowboy)
The Frameset fit is key, followed by wheels, quality and applicability to your
needs-the rest is minor in comparison-
Peter
Stacy Hills
Rick Denney wrote in message ...
>On Wed, 10 Mar 1999 19:06:08 -0500, "Johny Ringo" <Run...@ij.net>
>wrote:
>
>>QR's claim of Dura Ace doesn't go far (they say "blend"). I requested a
>>detailed spec sheet and plan to have them price one with 100% DA parts.
The
>>Cannondale is 100 Dura Ace stock. The QR frames are less, but the
>>workmanship seems less than the MS. QR's web site really doesn't have
specs.
>>
>>Does anyone have an opinion as to the value element between these two
>>choices, assuming the components were identical? I have a Trek road bike
now
>>so I don't have experience with either bikes, or bikes in general for that
>>matter.
>>
>
>The 'dale's seat tube is not as steep. I think it's 76 degrees,
>instead of the 78 used by QR.
>
The good Reverend Denney is wrong. I never thought I'd get to say that!!!
Cannondale has finally realized that triathletes want a true steep angle
bike and the new MS series bikes are 78 degrees for frame sizes 48-54 and 77
degrees for 56-62
http://www.cannondale.com/html/bikes/geometry/99caad4ams.html ). Isn't it
lovely to see these specs posted on a web site? (Yes that was a slam).
Don't ask me which bike I think is nicer looking because I own 3
Cannondales. I do agree the 'dales are a bit pricey but if you like the
ride...
I've seen Denney's Habanero and it's quite nice looking. I'm hoping that
he'll let me take a spin on it when this damn snow melts.
Stacy Hills
Reston, VA
Rick Denney
wrote:
I wrote:
>
>> The "blend" refers to a few changes in the parts mix that are made of
>> necessity for cost or configuration reasons. In particular, Dura Ace
>> chainrings do not come in the larger sizes that QR uses to offset the
>> effect of smaller wheels. The Stronglight crank that they use is the
>> top of Stronglight's line, but it is not as nice as a Dura Ace.
>
>i'd like to take exception to a couple of things you say here. first
>about the stronglight. i chose this crank because the medial side of each
>crankarm on either new dura ace or ultegra sticks out just over 1 cm from
>the frame vs stronglight's speedlight crank (or, for that matter, dura ace
>from the previous, non-tubular iteration). that's more than 2cm in total
>distance. i find new dura ace hard to ride if you like float in your
>cleats, as i kept banging my heels and maleoli on the crank. we've spec'd
>a lot of dura ace in our time and have no problem doing so now, when it's
>the right part. when it's not, we won't.
Yes, I did a bit of research on this and the crank is much narrower at
the spindle. I like this feature a lot. In fact, it's the main reason
I like the Campy cranks.
>
>> I agree that the QR frames are not as pretty in their construction
>> details as a Cannondale.
>
>this one hurts. i don't know, but i think the original writer may be
>describing the difference between smooth vs beaded welds, or maybe a
>formed downtube (most rst'ers know my view on that). maybe it's just
>personal preference, but i can't imagine a tequilo being considered the
>cosmetic inferior of the c'dale in attention to detail. but whatever
>floats your boat.
I was talking about the welds, not the attention to detail. I think
the QR's are plenty strong, and I said so in the part you snipped. But
the welds have a large bead compared with Cannondale's smooth fillet.
The latter is prettier to me, and to just about everyone I know. But I
balance that purely aesthetic concern against the geometry of the bike
and it's overall functionality and value, which makes it one small
point in the presence of many that are much more important.
>
>re the chainrings, we ourselves make a 55t pinned chainring for 9sp, we
>start with a stronglight and modify it ourselves. but we also use 11t 1st
>position. most of the time i prefer 53x11, only the baddest of the bad
>can reasonably handle 55x11. but that's what we put on the bike standard,
>we assume you're jurgen zack or spencer smith when you get the bike, if
>you're not then you've got to tone it down yourself if you want. so the
>choice of stronglight has nothing to do with the chainring sizes.
This is interesting, and differs from an account that I thought I
heard from you some time back. I do agree that 55/11 is overkill for
most folks. I ride a 52/12, and can spin quite slowly down hills up to
40+ mph. In the old days, we used to road race on 52/13 and 52/14
combinations, and we could draft. Going from a 12 to an 11 completely
accounts for the difference between 700 and 650 wheels, just as going
from a 52 to a 56 (or a 53 to a 57). Both at once provide a very tall
gear suitable, as you say, for Jurgen.
I'm sorry, though, I didn't mean to second-guess why you made your
choices. I was going on a story that I remembered and attributed to
you, that matched with my close inspection of the many QR bikes at
Bonzai.
Rick "suitably chastened" Denney
Cervelo Cycles
may expect I have taken a close look at Tequilos in the past. The thing that really
stood out for me was the weight. The C'dale Multisport frame weighs 4.25 lb for a
56cm size, quite a bit more than the Tequilo (or most other frames on the market
for that matter). While weight is not that important, it would be nice to get
something substantial in return for the extra weight. In the case of the C'dale,
that would be stiffness (the frame IS stiff), but with the way the tubes formed,
that would be mostly in the vertical plane, which is not something we really need.
Something else to consider is that while the C'dale now has a 78degree seattube
angle, it hardly has a dropped top tube. This means that you can get your saddle
forward, but you can not lower your bars very far. I am not saying this is good or
bad, it just means it is suitable for different people than the Tequilo (or the
Cervelo Eyre Tri). The Aegis Trident has a similar feature, as it has a relatively
long headtube. Great if you want to sit up high, but not that great if you are
looking for a low and aero aerobar position.
Sincerely,
Gerard Vroomen, Cervelo Cycles.
e-mail: intern...@cervelo.com
website: http://www.cervelo.com
Rick Denney
wrote:
>
>The good Reverend Denney is wrong. I never thought I'd get to say that!!!
Yes, alas, it happens. Occasionally. Keep it under your hat.
>
>Cannondale has finally realized that triathletes want a true steep angle
>bike and the new MS series bikes are 78 degrees for frame sizes 48-54 and 77
>degrees for 56-62
> http://www.cannondale.com/html/bikes/geometry/99caad4ams.html ). Isn't it
>lovely to see these specs posted on a web site? (Yes that was a slam).
>
Reviewing it, for the same top tube length, my Habanero has a taller
head tube and a longer wheelbase. The longer wheelbase I like. The
taller head tube would restrict how low you can go up front. It looks
sort of like Cannondale has gone to school on Quintana Roo.
But, Stacy, *your* 'dale tri-bike has a 75 degree seat tube. Right?
So, my information is just out of date.
The aero aspects of the Cannondale, on the other hand, are dubious at
best. It looks more like marketing gimmick than real aero design. Just
put one next to a P2 and you'll see what I mean.
>
>I've seen Denney's Habanero and it's quite nice looking. I'm hoping that
>he'll let me take a spin on it when this damn snow melts.
After exposing a mistake in front of God and everybody? Hmff.
Rick "two mea culpas in one thread is my limit" Denney
trinic
So let's talk about the weight of the Eyre-tri at the 56 cm frame height ?
On the other side the dropped top tube might not be something this
important for most of your customers who compete in ironman-distance races.
Not everybody can race for 5hours in a position he can sustain for 1h in an
olympic distance tri (at least I can't).
Trinic
Cervelo Cycles <intern...@cervelo.com> schrieb im Beitrag
<36E7FE06...@cervelo.com>...
Rick Denney
<intern...@cervelo.com> wrote:
>Something else to consider is that while the C'dale now has a 78degree seattube
>angle, it hardly has a dropped top tube. This means that you can get your saddle
>forward, but you can not lower your bars very far. I am not saying this is good or
>bad, it just means it is suitable for different people than the Tequilo (or the
>Cervelo Eyre Tri). The Aegis Trident has a similar feature, as it has a relatively
>long headtube. Great if you want to sit up high, but not that great if you are
>looking for a low and aero aerobar position.
>
This wasn't my impression looking at the dimensions on Cannondale's
web page, which Stacy provided. I'm comparing them with what I saw in
the store for QR, but the 'dale seem more like a QR than in years
past, especially concerning the dropped top tube. What you say is
precisely applicable to my Habanero, but it works for me.
I could have gotten a lower position by getting a smaller bike, say, a
54 instead of the 58. The head tube would have been 4cm shorter, like
the QR, and I would have had to use a 15 cm stem instead of an 11 to
get as stretched out as I want to be. And, of course, I'd have to show
4 cm more seat post. But then my knees would bang into my chest, I'd
have to arch my back to make clearance, and I'd defeat the whole
objective of getting comfortable on the bike. I know--that's exactly
how I fit on my Trek converted road bike.
Rick "Comfort is as important as aero efficiency, especially for
longer distances" Denney
Stacy Hills
>wrote:
>
>>
>>The good Reverend Denney is wrong. I never thought I'd get to say that!!!
>
>Yes, alas, it happens. Occasionally. Keep it under your hat.
>
Yes, of course. Sorry 'bout that.
< snip Rick's technical eyeing of the 'dale specs >
>But, Stacy, *your* 'dale tri-bike has a 75 degree seat tube. Right?
>So, my information is just out of date.
>
Yeah, if my memory is correct the smaller multisport frames were 76 degrees
and the larger ones, like mine at 60 cm, were 75 degrees.
One other Cannondale note is that you can now get them to build you a
"custom" frame with your choice of seat tube length, top tube length, BB
height(2 choices) and seat tube angle. It's the Caad 4 road frame (700c
wheels only) so you don't have to waste your money on the blimpish "aero"
frame. Trouble is, at least from what information is available on the web
site, the steepest seat tube you can get is 75 degrees.
>>
>>I've seen Denney's Habanero and it's quite nice looking. I'm hoping that
>>he'll let me take a spin on it when this damn snow melts.
>
>After exposing a mistake in front of God and everybody? Hmff.
Damnit, damnit, damnit. My big mouth always gets me into trouble. Rick, I
was only kidding...
Stacy Hills
Reston, VA
Johny Ringo
indeed-thanks! I got an email that brought up an interesting point that I
wanted to toss out to the group. Namely, is Easton aluminum used in QR's a
"better" ride than Alco, as utilized by C'Dale? With respect to my
application, I'm a 138lb rider. Hence, I've wondered just how relevant
differences in frame composition (alum, carbon, etc.) are given the stress
my weight would apply. From what I've gathered, clearly ones "triangle"
needs to be the driving factor in selecting the best fit in either frame.
But given a near similar fit in each, would the type of aluminum matter. For
that matter, do you all think that I would feel a difference riding and
aluminum vs. carbon at 138lbs. I'm on a 1996 Trek 2100 ZX carbon now, and
really have not been on an aluminum frame.
Rick Denney wrote in message
<0A0940A90D73E431.98E800C3...@library-proxy.airnews.ne
t>...
Dan Empfield
<846792FF2FEA2ACC.A41367C8...@library-proxy.airnews.net>,
r...@odetics.com wrote:
> This wasn't my impression looking at the dimensions on Cannondale's
> web page, which Stacy provided. I'm comparing them with what I saw in
> the store for QR, but the 'dale seem more like a QR than in years
> past, especially concerning the dropped top tube. What you say is
> precisely applicable to my Habanero, but it works for me.
my understanding is that the better of the tri frames does have steeper
angles, although there are some other geometric areas in which it did not
make the necessary (so it seems to us) revisions, such as head tube
lengths. but i do believe they are steeper than they were. i haven't
checked the finer points of the bikes, such as where the front derailleur
sits in relation to the crank, etc.
qrman
Joe Foster
I was commenting on the 56/11 combination, which, even with 650 wheels, is a real monster.Nice, nice monster, when the wind is at your back Hawi to Kailua <G> WEEEEEEEEeeeeeeeee!
Aloha,
Joe
__________________________________________________________
Joe Foster
jcfo...@ix.netcom.com
__________________________________________________________
"The idea is to create your own future, and not have it shaped by
circumstance." - Peter Thomas
__________________________________________________________
mather callaghan
but i'm a strong cyclist (18 inch calves -- ewww). i ride an old school
kestrel km-40 (the kind WITH a seat tube) w/ 650 wheels. anyway, am I a
freak of nature for pushing a 56 x 12? i like it. i'm a power ride, and
it's pretty flat where i live, but all this talk is making me feel like i'm
some kind of nutjob.
mike "feeling insecure and big-legged" callaghan
Rick Denney
wrote:
>You all are obviously experts and your comments are very helpful
>indeed-thanks!
Flattery will get you everywhere.
>I got an email that brought up an interesting point that I
>wanted to toss out to the group. Namely, is Easton aluminum used in QR's a
>"better" ride than Alco, as utilized by C'Dale?
Aluminum is aluminum is aluminum. The only differences are strength,
tubing shape, and wall thickness. Assuming it is strong enough (which
the tubes in QR's and Cannondales are) the elasticity is the same in
all of them.
>With respect to my
>application, I'm a 138lb rider. Hence, I've wondered just how relevant
>differences in frame composition (alum, carbon, etc.) are given the stress
>my weight would apply.
You don't need as stiff a frame for it to feel stiff. Road vibration
is not what I'm talking about here, though there may be slight
differences between bikes in that category.
>From what I've gathered, clearly ones "triangle"
>needs to be the driving factor in selecting the best fit in either frame.
>But given a near similar fit in each, would the type of aluminum matter. For
>that matter, do you all think that I would feel a difference riding and
>aluminum vs. carbon at 138lbs. I'm on a 1996 Trek 2100 ZX carbon now, and
>really have not been on an aluminum frame.
>
You will feel a difference between carbon and aluminum. Carbon damps
road buzz, and elastic metals like aluminum do not. The carbon bikes
will feel more quiet, and the metal bike will feel more alive. Or,
depending on what's important to you, you could say that the carbon
bike feels dead and the metal bike rattles your fillings.
But I doubt you could feel a difference between similar bikes that use
Easton tubes and other tubes. But QR's and Cannondales have different
geometry, and that can make them feel differently, too.
Rick "Ride them both, and then you'll know" Denney
Rick Denney
<mike.ca...@utoronto.ca> wrote:
>ok, i've been interested by all this talk of teeth. i'm only 19 yrs old,
>but i'm a strong cyclist (18 inch calves -- ewww). i ride an old school
>kestrel km-40 (the kind WITH a seat tube) w/ 650 wheels. anyway, am I a
>freak of nature for pushing a 56 x 12? i like it. i'm a power ride, and
>it's pretty flat where i live, but all this talk is making me feel like i'm
>some kind of nutjob.
>
Actually, a 56/12 with 650 wheels is nearly identical to a 52/12 with
700 wheels. That's a pretty normal top gear. I was commenting on the
56/11 combination, which, even with 650 wheels, is a real monster.
Rick "What you have sounds reasonable to me" Denney
Mike Bundy
With 650 wheels, the situation may (should?) be different. I think that
Gerard may be suggesting that the C'Dale is not taking full advantage of
it's wheel size.
I didn't appreciate the virtues of a dropped top tube until I raced my
P2 for the first time.
-- MB.
Rick Denney wrote in message
<846792FF2FEA2ACC.A41367C8...@library-proxy.airnew
s.net>...
>On Thu, 11 Mar 1999 12:31:50 -0500, Cervelo Cycles
><intern...@cervelo.com> wrote:
>
>>Something else to consider is that while the C'dale now has a 78degree
seattube
>>angle, it hardly has a dropped top tube. This means that you can get
your saddle
>>forward, but you can not lower your bars very far. I am not saying
this is good or
>>bad, it just means it is suitable for different people than the
Tequilo (or the
>>Cervelo Eyre Tri). The Aegis Trident has a similar feature, as it has
a relatively
>>long headtube. Great if you want to sit up high, but not that great if
you are
>>looking for a low and aero aerobar position.
>>
>
>This wasn't my impression looking at the dimensions on Cannondale's
>web page, which Stacy provided. I'm comparing them with what I saw in
>the store for QR, but the 'dale seem more like a QR than in years
>past, especially concerning the dropped top tube. What you say is
>precisely applicable to my Habanero, but it works for me.
>
Rick Denney
<mbu...@OzEmail.com.au> wrote:
>Unless I'm mistaken, your Habanero is based on 700 wheels, is it not??
>With 650 wheels, the situation may (should?) be different. I think that
>Gerard may be suggesting that the C'Dale is not taking full advantage of
>it's wheel size.
>
>I didn't appreciate the virtues of a dropped top tube until I raced my
>P2 for the first time.
>
Yes, Gerard's comments were specifically directed at the small-wheeled
Cannondale. But they do apply to the Habanero as well. My Habbie could
have been designed with a lower top tube--there's nothing about the
large wheels that restricts this in a frame of that size. But then I
would have had to use an upward-sloping stem, because I can't get that
low in the front without my knees banging into my chest. A lot of
folks are younger, thinner, less deep-chested, and more bendable than
me, but there are a lot of folks that aren't. What a pity it would be
if all bikes were the same!
Rick "Viva L'Difference!" Denney
Stacy Hills
Luhrman(sp?) who ripped it off from someone else.
Stacy Hills
Reston, VA
mather callaghan wrote in message ...
>ok, i've been interested by all this talk of teeth. i'm only 19 yrs old,
>but i'm a strong cyclist (18 inch calves -- ewww). i ride an old school
>kestrel km-40 (the kind WITH a seat tube) w/ 650 wheels. anyway, am I a
>freak of nature for pushing a 56 x 12? i like it. i'm a power ride, and
>it's pretty flat where i live, but all this talk is making me feel like i'm
>some kind of nutjob.
>
Dan Empfield
<0A0940A90D73E431.98E800C3...@library-proxy.airnews.net>,
r...@odetics.com wrote:
> Yes, I did a bit of research on this and the crank is much narrower at
> the spindle. I like this feature a lot. In fact, it's the main reason
> I like the Campy cranks.
i'm not going to wail on you about this, because you MOSTLY are right on
target in everything you say, you're generally VERY helpful to people,
and you don't jobst all over whomever disagrees with you. THAT SAID, i'll
remind you of what else you said...
>The Stronglight crank that they use is the
>top of Stronglight's line, but it is not as nice as a Dura Ace.
now what did you mean when you said this last thing? i suppose when you
said "IS" you have to wonder what your particular meaning of IS is, but
even more to the point is your use of the word NICE. now when you say the
crank we chose is not as NICE as dura ace, are you saying it is not as
FUNCTIONAL as dura ace, or it is not as PRETTY as dura ace, or it is not
made with an equivalent (i.e., welded together pieces of forged
sub-assemblies w/ a splined BB) TECHNOLOGY as dura ace ( i pretty much
think the stronglight speedlight is pretty darn pretty, if it's pretty
you're talking about).
maybe you think i'm being picky, but the average bum walking down the
street and stumbling into a bike shop, and falling down with his nose
landing right in front of a QR might say, "hey, QR is using a stronglight
crank, those chintzos are trying to chintz out on the crank! but the
TRAINED EYE might observe that QR chose a crank that is, oh by the way the
same price, pretty much, as DA, but actually has functionality that the DA
does not have.
this picking and choosing of parts gets us into trouble with a variety of
dealers and customers who are used to the GRUPPO concept, but it just
seems to me that the gruppo thing is the lazy way out, which yields you
brake levers, cranks, saddles, handlebars, rims, tires, forks, blah blah,
that don't have the functionality that a triathlete needs for HIS/HER
particular usage.
of course we blow it now and then, we blew it a couple of years ago with
both brake calipers and bottom brackets (we were in a hole trying to come
up with the 103mm spindles and chose poorly on our BB vendor). but you
live and learn.
this issue is a particular one for me, as i'm constantly having to make my
own parts, which is expensive. so i went out and bought a whole durned
parts company (real design), and spent another pile on a four axis CNC
horizontal mill and new versions of autocad and thrifty cad and solidworks
or solidwaste and mastercam or cameraman or whatever thirty or forty thou
in software will get you, so as to make parts that neither campy, shimano,
or others have available for me to buy.
i think i'll have my boys use some of that fancy software to design a
maleolus protector you can strap on, so those who choose to buy the OTHER
guys' cranks can have as pretty and pure a set of maleoli as the QR riders
out there.
so that's all i'll say about that (at least on this post).
qr (defends his spec against all comers) man
Cervelo Cycles
Mike Bundy wrote:
> Unless I'm mistaken, your Habanero is based on 700 wheels, is it not??
> With 650 wheels, the situation may (should?) be different. I think that
> Gerard may be suggesting that the C'Dale is not taking full advantage of
> it's wheel size.
>
> I didn't appreciate the virtues of a dropped top tube until I raced my
> P2 for the first time.
>
> -- MB.
First of all, if my comments seem out of place these days, it may be due to
the fact that my browser is acting weirdly, and I seem to be missing a lot
of posts. Or maybe I'm simply an idiot.
Anyway, I am not really saying that there is something wrong with the
C'dale's geometry, I just wanted to point out that it is different from some
of the other bikes discussed. Compared to the Cervelo, it is 5cm longer,
which means that the lowest you can go on the C'dale is about the highest we
ever set somebody up on a Cervelo. Usually people only use a couple of
spacers on a Cervelo (definitely less than 5cm), and are thus in a position
they couldn't obtain on the c'dale, unless they use an Ergostem or other
special device (which I would not recommend for daily use, but it's great
for testing different positions).
This is not necessarily bad, I know that our geometry works for our
customers, and I hope Cannondale's geometry works for their customers. I
think that our headtube length is reasonable for a lot of people, and thus
that C'dales headtube length is a bit on the long side. But again, that will
work for those who find our headtubes too short and vice versa.
Cervelo Cycles
> you're not then you've got to tone it down yourself if you want. so the
> choice of stronglight has nothing to do with the chainring sizes.
>
I really disagree with you on this point. A lot of triathletes push too big a gear,
and QR spec'ing a 55x11 doesn't exactly help. I presume you know that most of your
customers aren't Jurgen Zack or Spencer Smith, so why send them the 55x11.
I think most consumers don't swap them and end up with too big a gear. In fact,
most retailers have no idea that you send your bikes with too big a gear, and
complain to other triathlon bike manufacturers who send their bikes with the
correct gear that their gears are too small. These retailers definitely aren't the
ones who will suggest to your customers that they should switch rings.
The other possibility is that the retailer does know about all this and the
customer swaps rings and gets charged extra by the bike shop (unless the shop wants
to swap it for free, but how many 55t rings can a shop pile up unless they get
regular calls from Jurgen for some fresh ones).
On top of this, shipping the bike with a 55x11 perpetuates the notion among some
people that a tri bike is per definition undergeared, which obviously is not the
case now that the 11t cog is standard issue on many cogsets.
Dan Empfield
<intern...@cervelo.com> wrote:
hey, cool, me and you again. but this time you might be surprised to hear
that i think you're exactly right. to understand our position on this,
you'd have to go back a decade, when we invented this whole concept, and
were confronted with interesting arguments which you (happily for you and
us) don't have to much deal with in this day and age (i say "much" have to
deal with for reasons below).
we had a dealer who got really mad at us here in san diego, because his
credit sucked and we wouldn't sell him bikes on terms, and yet we still
sold an awful lot of our bikes in SD, through places like nytro. so he
ran this ad that indicated how slow QR bikes were, his thesis, believe it
or not, was simply this, that if you put it into say, a 53 x 13 on HIS
(700c) bike, and pedaled at, say 85rpm, you'd go, you know, whatever miles
an hour. on a QR you'd only go "this many" miles per hour.
now that sounds pretty stupid to you, but this really was emblematic of
the asinine mentality we had to deal with all over the country. the
problem is, IT STILL EXISTS!! i say this because you youself comment
below, that what we do, "perpetuates the notion among some people that a
tri bike is per definition undergeared." you can't perpetuate something
that doesn't alredy exist. well our bike sure aint undergeared with 120
gear inches, is it? this saves our salespeople about 20% of their day.
but to be honest, gerard, half the bikes we send out go out 53 X 42 or 39,
because we explain this whole gearing thing upfront to all our dealers,
and if a dealer wishes to put on what we might consider a more reasonable
gear for the masses, we'll spec it that way. but hey, if you ARE a
hammerdog, i guess you just want the big meat, and really, we have NO pro
triathletes out there, of the twenty odd who ride for us, that want
anything less than 55 X 11, and they really come across circumstances when
they need every inch of it. we've got to talk a lot of them DOWN to 55 X
11, they want 56, 57, 58.
as to the 55's piling up i shops and shops taking advantage of customers,
blah blah, we are pretty picky with which shops we do business with. many
shops really hate our guts because we won't sell them the one or two bikes
they want each year, i HOPE the few shops we install to do business with
us don't do that sort of thing. we DO march around the country and put on
clinics at these stores (i think we're in ohio now), and we clinic the
stores heavily on this stuff. i guess you theoretically have a point, but
i doubt it is much of a problem with our retailers, i can't speak for
c'dale and other dealers.
since we DO tell our dealers that they might want to consider 53t, and
since many of them take advantage of this option, we in fact ARE the place
that has a lot of 55t piling up, so if you just can't convince all your
customers to go 53t and need some 55t rings that really work with 9sp you
can give me a call.
all kidding aside, gerard, you have a very good point, as usual, and most
650c bikes should go out 53t, if not 52t, including yours and mine. i am
currently riding a 55x42, 11x21 redstone, and i can easily go 24mph in the
12t and the small ring, i could break the sound barrier in the big ring if
i had legs.
zenhound
Dan Empfield wrote:
> In article
> <E2EEECC3EF0660C0.F5F8AB8C...@library-proxy.airnews.net>,
> r...@odetics.com wrote:
>
> re the chainrings, we ourselves make a 55t pinned chainring for 9sp, we
> start with a stronglight and modify it ourselves. but we also use 11t 1st
> position. most of the time i prefer 53x11, only the baddest of the bad
> can reasonably handle 55x11. but that's what we put on the bike standard,
> we assume you're jurgen zack or spencer smith when you get the bike, if
> you're not then you've got to tone it down yourself if you want. so the
> choice of stronglight has nothing to do with the chainring sizes.
>
> qrman
I'm confused by your comment above. Do you mean that the Tequilo has a
configuration that in your opinion only a very small portion of the tri population
can handle? Did I misunderstand what you meant? I would normally assume that the
base specifications would suit most riders.
I ordered my new Tequilo on Wednesday from my LBS in Ann Arbor (at your roadshow by
the way, which is great idea). When I ordered the bike, I didn't even think of
changing the front chainring. If I would be better suited to a 53X11 setup, I'd
like to make the change before they have the bike built up.
Sorry for the bandwith. I don't normally speak up during these more technical bike
discussion. I prefer to simply try to learn as much as I can from you all, but
this comment hit a little close to home.
Peter Zein
Grant Beauprez
I were you. You are not a freak. Just use those big hams at the end of
your hips to your advantage.
Grant "wish I could push a 56x12" Beauprez
Enduro Sport Dan
callaghan" <mike.ca...@utoronto.ca> wrote:
> ok, i've been interested by all this talk of teeth. i'm only 19 yrs old,
> but i'm a strong cyclist (18 inch calves -- ewww). i ride an old school
> kestrel km-40 (the kind WITH a seat tube) w/ 650 wheels. anyway, am I a
> freak of nature for pushing a 56 x 12? i like it. i'm a power ride, and
> it's pretty flat where i live, but all this talk is making me feel like i'm
> some kind of nutjob.
Mike,
56x12 on 650C wheels is buy no means an unreasonable gear. In the future
(when you need to replace your cassette) you may want to consider using a
cassette with an 11T cog. This is the best way to make up for the
difference between 650 and 700C wheels. It will allow you to go back to a
53T chainring and either:
a) used a 39T small ring if/when necessary.
or
b) stick with your 42T small ring and enjoy better front shifting.
But regardless, Mike, I can assure you that you are not a nutjob.
Yours in good mental health,
Dan Rishworth
Enduro Sport - Your Multi-Sport Pro Shop
1.800.448.4678
http://www.endurosport.com
Martha Peacock
they have gone to 78 degrees this year. I thought you might want to
know.
Enduro Sport Dan
> On Thu, 11 Mar 1999 12:31:50 -0500, Cervelo Cycles
> <intern...@cervelo.com> wrote:
>
> >Something else to consider is that while the C'dale now has a 78degree
seattube
> >angle, it hardly has a dropped top tube. This means that you can get
your saddle
> >forward, but you can not lower your bars very far. I am not saying this
is good or
> >bad, it just means it is suitable for different people than the Tequilo
(or the
> >Cervelo Eyre Tri). The Aegis Trident has a similar feature, as it has a
relatively
> >long headtube. Great if you want to sit up high, but not that great if
you are
> >looking for a low and aero aerobar position.
> I could have gotten a lower position by getting a smaller bike, say, a
> 54 instead of the 58. The head tube would have been 4cm shorter, like
> the QR, and I would have had to use a 15 cm stem instead of an 11 to
> get as stretched out as I want to be. And, of course, I'd have to show
> 4 cm more seat post. But then my knees would bang into my chest, I'd
> have to arch my back to make clearance, and I'd defeat the whole
> objective of getting comfortable on the bike. I know--that's exactly
> how I fit on my Trek converted road bike.
Rick,
The point that Gerard is making is not that a Cervelo or a QR would be a
smaller bike or that they fit smaller, but that the geometry that they use
gives the rider the _potential_ to achieve a lower position on these
frames than the same rider could on their size of Cannondale MSxxxx or
Aegis Trident. When we (Enduro Sport) evaluated the MS2000 we found
several differences between it and bikes like QR and Cervelo, but the
difference in head tube is a big one. With a 78deg seat tube angle the
position the an average rider can _comfortably_ achieve on a QR or Cervelo
(that is, our conservative starting position) would be the _lowest_
position possible on a Cannondale. Most riders we set-up on a QR or
Cervelo (or any other bike with similar geometry, of course) make the
adjustment to a tri bike and find that they can gradually lower their bar
height to imporve their position in the aerobars. With Cannondale's head
tube length this possibility just doesn't exist.
The issue of a smaller frame with a longer stem (affecting weight
distribution) and your knee hitting your chest (compressed hip angle) are
not usually an issue the way we set athletes up on advanced position (tri)
bikes. This seems consistent with your experience on your converted road
bike.
I'd be interested in knowing more about the geometry of your Habbie.
Enduro Sport Dan
<50F663B921B5A419.C49EF756...@library-proxy.airnews.net>,
r...@odetics.com wrote:
> On Thu, 11 Mar 1999 20:12:57 -0500, "Johny Ringo" <Run...@ij.net>
> wrote:
> >I got an email that brought up an interesting point that I
> >wanted to toss out to the group. Namely, is Easton aluminum used in QR's a
> >"better" ride than Alco, as utilized by C'Dale?
>
> Aluminum is aluminum is aluminum. The only differences are strength,
> tubing shape, and wall thickness. Assuming it is strong enough (which
> the tubes in QR's and Cannondales are) the elasticity is the same in
> all of them.
I'm not sure that this is on point. The differences in tube shape and wall
thickness will have a dramatic impact in how a bike rides or feels. The
most obvious case in point would be to compare a Vitus or Alan standard
diameter aluminum from from the 80s to the early Cannondale frames which
used oversize aluminum tubes. While the Vitus and Alan frames were soft
(comfortable) noodles the Cannondales were super stiff in both laterally
(good for power transmission) and vertically (bad for comfort). Similarly
the comparison is valid today in comparing the variety of designs and tube
shapes available in aluminum road and tri bikes. From QR to Cervelo to
Cannondale MS800 to Cannondale MS2000 to Javelin TriLite, there are lots
of builders making aluminum bikes and by virtue of the way their tubes are
designed and the frames constructed they will all ride differently.
The main decision that you need to make, Johny, is choosing your builder
(ie. QR, Cervelo, Cannondale, etc). In doing so you are choosing that
builders design and construction choices and in the hands of a good
builder/frame designer almost any material (Al, Ti, Steel, Carbon) can be
used to make a good bicycle frame.
Dan Empfield
> I'm confused by your comment above. Do you mean that the Tequilo has a
> configuration that in your opinion only a very small portion of the tri
population
> can handle? Did I misunderstand what you meant? I would normally
assume that the
> base specifications would suit most riders.
what i mean is that we build our bikes so that you can take them out and
race them with no additions made beforehad, or excuses made afterward. we
assume that you are a reasonably good athlete, or you wouldn't be riding
aero bars to begin with. i feel there is a decent percentage of those
racing triathlons who shouldn't be riding with aero bars at all. i make
this statement because when i see the way they've set up their bikes, aero
bars are doing them absolutely no good, and they'd be better off without
them.
if you're talented and competitive, let us say you're near the top of any
men's age group below, say, 45 - 49, there are times you'd miss not having
a 55t ring, especially on certain types of rolling courses, like zofingen
and hawaii. on the other hand, i think having a big ring on the bike is
an invitation to ride a slower cadence than what you might normally ride,
and i think this is the biggest concern with having a 55t big ring.
realize that 55x11 is not the ONLY gear on the bike, it is the BIGGEST
gear on the bike. we're haggling on whether you want your biggest gear to
be something like 116" or 120" (53X11 or 55X11). you've got 16 usable
configurations on a bike equipped 55X42, 11/21, with the smallest, 42x21
on 650c, about the same as 42x23 or 24 on 700c, which is a fairly small
gear.
> I ordered my new Tequilo on Wednesday from my LBS in Ann Arbor (at your
roadshow by
> the way, which is great idea). When I ordered the bike, I didn't even
think of
> changing the front chainring. If I would be better suited to a 53X11
setup, I'd
> like to make the change before they have the bike built up.
if you step back for just a moment and consider the broader ramifications
of this discussion, this is really emblematic of what has been bothering
me about this business since i got into it, and really even before that,
when i was just a triathlete trying to find the right stuff for me to
ride. i was a uscf racer in the late '70's, i started with a raleigh
international, eventually went to a colnago super, raleigh pro, and a
custom made della santa. for all these bikes, it was quite understood
that i would work with my LBS to make the bike appropriate for me, and
really, the FIRST thing you do is consider gearing, both front and back.
then you talk about whether the saddle, handlebar bends and width, stem
length and pitch, tire choice, etc., are appropriate for you. i'm even
picky about which handlebar tape i ride.
i don't know whether it is the way LBS's look at triathletes, or that
triathletes don't demand, or know to demand, this type of service. but
roadies do. realize that there is no gearing we could put on the bike
that would be the "right" gearing, and you should all demand, when you buy
a $1500 or $2500 bike, that the gearing is right for you, at no extra
charge! (so long as you aren't asking for anything weird). this is the
minimal amount of service that should be provided!
so the loooong answer to your question, is, i don't know if you should
consider changing your choice of big ring. it depends on you, what you
intend to race, how fit you are, what your terrain is, and of course what
you choose both for your small ring, and for your cogset. we offer three
chainring pairings from which the dealer may choose, which is, by the way,
two more pairings than most other bike maker will offer, and they are
55x42, 53x42, and 53x39. we offer 11/21 9sp in the rear, but i do believe
we also offer 11/23, i'm not sure (it depends on what shimano offers us).
what i would do is talk to tom demerly, and ask him what he thinks you
ought to ride, and certainly have the bike built that way. dealers should
have no qualms about working with you on gearing configurations, and a
switch of chainrings from 55t to 53t should not cost you anything. for
bike makers offering only 53t, though, and if you wanted to go to 55t,
THIS might cost you something, as we are to my knowledge the only company
out there offering a 55t 9sp chainring that is any good, and dealers that
don't know where to get such rings might be prone to charge for such a
swap.
finally, before you jump to the conclusion that you're 55x11 QR is
overgeared, realize that current road race bikes configured 53x11 or 52x11
have gearing about equivalent to a 55x11 650c bike.
qrman
mather callaghan
in a few years.
mike "can't say no to a few more asprin" callaghan
Mark Hickey
>finally, before you jump to the conclusion that you're 55x11 QR is
>overgeared, realize that current road race bikes configured 53x11 or 52x11
>have gearing about equivalent to a 55x11 650c bike.
The way I calculate it...
52x11, 700c equals 56x11, 650c
53x11, 700c equals 57x11, 650c
That's either 1.8% or 3.6% "bigger" gearing on the 700c bike, if
you're comparing a 52 or 53 700c bike to a 55 650c bike.
Whether that makes a difference or not depends on the individual, of
course.
Mark Hickey
Habanero Cycles
http://www.cynetfl.com/habanero/
My ISP is having BIG problems right now.. hope to have the site and
Email back on line soon...
Mark Hickey
>r...@odetics.com wrote:
>
>> Aluminum is aluminum is aluminum. The only differences are strength,
>> tubing shape, and wall thickness. Assuming it is strong enough (which
>> the tubes in QR's and Cannondales are) the elasticity is the same in
>> all of them.
>
>I'm not sure that this is on point. The differences in tube shape and wall
>thickness will have a dramatic impact in how a bike rides or feels.
While this is true for the extremes (i.e. C'dale vs Vitus) to a point,
it's not going to make a heck of a lot of difference for "similar"
frames. That is, going from one tubeset to the one above or below it
won't usually make enough difference for most riders to discern
(proven in blind tests). Unless the tubing is tortured into some VERY
unusual shapes (i.e. something flat like the venerable Hooker frames),
it's going to act quite a bit like a round tube in most respects.
>The
>most obvious case in point would be to compare a Vitus or Alan standard
>diameter aluminum from from the 80s to the early Cannondale frames which
>used oversize aluminum tubes. While the Vitus and Alan frames were soft
>(comfortable) noodles the Cannondales were super stiff in both laterally
>(good for power transmission) and vertically (bad for comfort).
The "comfort" of a whippy frame is "common knowledge", but without
basis. Don't expect a bike frame to make a significant difference in
comfort. They just aren't capable of flexing vertically enough to
matter - the tires, bars, saddle, rims, fork, etc all contribute many
times more vertical compliance than the frame can. But the
improvement in lateral stiffness DOES make a difference, especially in
sprinting, cornering and climbing.
> Similarly
>the comparison is valid today in comparing the variety of designs and tube
>shapes available in aluminum road and tri bikes. From QR to Cervelo to
>Cannondale MS800 to Cannondale MS2000 to Javelin TriLite, there are lots
>of builders making aluminum bikes and by virtue of the way their tubes are
>designed and the frames constructed they will all ride differently.
More a function of different geometry than different tubing, though.
>The main decision that you need to make, Johny, is choosing your builder
>(ie. QR, Cervelo, Cannondale, etc). In doing so you are choosing that
>builders design and construction choices and in the hands of a good
>builder/frame designer almost any material (Al, Ti, Steel, Carbon) can be
>used to make a good bicycle frame.
Very true. Lots of great bikes out there in each of those categories.
Dan Empfield
Hickey) wrote:
> >finally, before you jump to the conclusion that you're 55x11 QR is
> >overgeared, realize that current road race bikes configured 53x11 or 52x11
> >have gearing about equivalent to a 55x11 650c bike.
>
> The way I calculate it...
>
> 52x11, 700c equals 56x11, 650c
> 53x11, 700c equals 57x11, 650c
well, then, there you go. i'm UNDERgearing my bikes, it looks like. i'm
going to have to go out and find some big meat to slap on those babies.
qrman
BPSullivan
>finally, before you jump to the conclusion that you're 55x11 QR is
>overgeared, realize that current road race bikes configured 53x11 or 52x11
>have gearing about equivalent to a 55x11 650c bike.
For what it's worth, I have a 55x11 QR, and I run at 20mph for 40k on a flat
course. That is, of course, not exactly competitive. So, you say, why the hell
are you pushing such a big gear? Isn't your cadence too slow? Fact is, I only
push that gear DOWN HILL. (Sorry for the shout) There are plenty of other gear
ratios available to me to keep my cadence at 90 rpm. But let me tell you, when
I am on a long down slope, and I really want to crank it out, I love having the
big hammer to throw around. As my LBS tech reminded me when I thought of
trading the 11 for a 23 to climb hills - this is a time-trial racing bike. Even
though I'm not Jurgen Zack, if I'm in this to have fun I might as well have a
big-time top end to play with. So I kept the 11, added the 23, and dropped
something in the middle. Now I can go up hills like the tortoise I am, and go
down hills like the hare I would like to be.
Brian Sullivan
bpsul...@aol.com
Rick Denney
wrote:
[The flattery will get you everywhere part snipped. The only reason
I'm saying it's snipped is so that people will be curious, and go back
into the thread and read it, heh, heh.]
>
>>The Stronglight crank that they use is the
>>top of Stronglight's line, but it is not as nice as a Dura Ace.
>
>now what did you mean when you said this last thing? i suppose when you
>said "IS" you have to wonder what your particular meaning of IS is, but
>even more to the point is your use of the word NICE. now when you say the
>crank we chose is not as NICE as dura ace, are you saying it is not as
>FUNCTIONAL as dura ace, or it is not as PRETTY as dura ace, or it is not
>made with an equivalent (i.e., welded together pieces of forged
>sub-assemblies w/ a splined BB) TECHNOLOGY as dura ace ( i pretty much
>think the stronglight speedlight is pretty darn pretty, if it's pretty
>you're talking about).
I like the pearl anodizing, and the cranks really glitter. I didn't
much care for the laser-etched logo, but that's me. But the finish
polishing isn't quite as good as DA or a Campy. It had lots of tiny
forging pits that were not fully polished out. This is entirely
aesthetic, and I'm really picky. It has nothing to do with
function--the presence of forging pits means they are forged, which
beats all hell out of CNC cranks. Next time I'll be more specific.
I almost bought a Speedlite track set for my track frame last fall,
but N**** (large SoCal shop) wouldn't give me the price I wanted. I
didn't want the top of the line. I wanted what I ended up with: a
Sugino Track Crank at about half the price of the Stronglight. But it
ain't nearly as pretty as the Speedlite.
>
>this picking and choosing of parts gets us into trouble with a variety of
>dealers and customers who are used to the GRUPPO concept, but it just
>seems to me that the gruppo thing is the lazy way out, which yields you
>brake levers, cranks, saddles, handlebars, rims, tires, forks, blah blah,
>that don't have the functionality that a triathlete needs for HIS/HER
>particular usage.
With this I absolutely agree. I could not, in fact, agree more. I do
respect tremendously manufacturers who pick and choose parts to make
the bike more valuable. On the other hand, I've seen scurrilous
manufacturers (present company definitely excluded) use this as an
excuse to trade out relatively invisible parts (like the hubs, BB's,
and headsets) for cheapies, while the showy derailleurs and cranks
were the good stuff. People who look at my bikes will see a homey mix
of parts--I've never yet built a bike with a gruppo, and probably
never will. [/shameless_plug_mode ON] By the way, I'll have several of
my bikes at the QR Road Show at Bonzai Sports in Fairfax on the 27th,
for those of you in the DC area who want to peruse them and laugh at
how out-of-date they are (only 8 speeds and all). Then you can look at
the pretty new bikes we've been talking about. I will be helping out,
and I'm really looking forward to it. [/shameless_plug_mode OFF]
This is especially true for triathlon bikes. Mine has an Ultegra rear
derailleur and downtube shifters (mounted on the aerobars), a Dura Ace
front derailleur, a Chorus crank, a Record BB, Spinergy wheels, a
Stronglight headset (the best in the business, in my view), Brew
hot-rodded BRS 200 brakes, Dia-Compe reverse-pull levers, Syntace
cowhorns and aerobars, Salsa stem, Syncros seatpost, and Speedplay
pedals. The only two parts that match are the rear derailleur and the
shifter. A veritable cornucopia of on-sale parts deals and trade
fodder, 'cept for the frame, of course.
>this issue is a particular one for me, as i'm constantly having to make my
>own parts, which is expensive. so i went out and bought a whole durned
>parts company (real design), and spent another pile on a four axis CNC
>horizontal mill and new versions of autocad and thrifty cad and solidworks
>or solidwaste and mastercam or cameraman or whatever thirty or forty thou
>in software will get you, so as to make parts that neither campy, shimano,
>or others have available for me to buy.
>
>i think i'll have my boys use some of that fancy software to design a
>maleolus protector you can strap on, so those who choose to buy the OTHER
>guys' cranks can have as pretty and pure a set of maleoli as the QR riders
>out there.
I bow down to thee, oh great Maleolus Man!
Oops, I probably messed up with my crack (so to speak) about CNC
cranks. The Maleolus Man will not be through with me yet.
Rick "Cowering" Denney
Rick Denney
Dan) wrote:
>
>Rick,
>
>The point that Gerard is making is not that a Cervelo or a QR would be a
>smaller bike or that they fit smaller, but that the geometry that they use
>gives the rider the _potential_ to achieve a lower position on these
>frames than the same rider could on their size of Cannondale MSxxxx or
>Aegis Trident.
Yes. I made this point in other posts. Both the Cervelo and the QR use
a substantially dropped top tube, which allows a rider that is
bendable enough to get really low in the front. But the 'dale seems to
have a lower top tube and a shorter head tube than in years past.
That, and the switch to a true 78-degree seat tube, tells me that
they've been going to school on the competition.
> When we (Enduro Sport) evaluated the MS2000 we found
>several differences between it and bikes like QR and Cervelo, but the
>difference in head tube is a big one. With a 78deg seat tube angle the
>position the an average rider can _comfortably_ achieve on a QR or Cervelo
>(that is, our conservative starting position) would be the _lowest_
>position possible on a Cannondale. Most riders we set-up on a QR or
>Cervelo (or any other bike with similar geometry, of course) make the
>adjustment to a tri bike and find that they can gradually lower their bar
>height to imporve their position in the aerobars. With Cannondale's head
>tube length this possibility just doesn't exist.
Yes. This is also true of my Habanero, which has a relatively long
head tube tube. But it also has a relatively long top tube, and I
could have gotten a smaller frame and used a bit longer stem. I still
would have had a stem shorter than the one on my converted road bike,
and could have gotten fairly low. I would still have had a
great-handling bike, because the weight balance and trail would have
been much better. I'm not sure I could have gotten as low as on a QR
or a Cervelo.
But it doesn't matter, because I just can't bend that much in the
middle. I'm very deep-chested, and my thighs bang into my ribs. I'd
rather stick up a tad higher and be really comfortable on the bike,
especially if I'm going to ride the damn thing 112 miles, which is
what I want to do someday.
>
>The issue of a smaller frame with a longer stem (affecting weight
>distribution) and your knee hitting your chest (compressed hip angle) are
>not usually an issue the way we set athletes up on advanced position (tri)
>bikes. This seems consistent with your experience on your converted road
>bike.
The Thigh-Rib Controversy is not because of the compressed hip angle.
The converted road bike and the Habanero both had effective 78-degree
seat tubes. The problem is congenital spondylolisthesis, which is an
anterior displacement of the lower spine of about one cm, plus a round
cross-section through the rib cage instead of the Surfer-Dude flat
configuration. The little bit of belly we won't discuss, at least not
if you want me to stay civil. With the road bike (a Trek 5500), it
took a Profile seat post (yuck) to get there, which had the effect of
making the top tube considerably shorter. But the Trek had a dropped
top tube, and I could have gotten very low on it if I had wanted to.
But I still ended up with an upward-sloping Salsa stem (of 16 cm
length) to resolve the Controversy. On the Habbie, I'm using a
shorter stem (about 10 cm, as it turned out, at least for now). I
could easily have fit myself on a 54 instead of the 58, and used a 14
cm stem, and been four cm lower in the front. But then my damn knees
would be banging into my chest again.
And here's the Dilbert in me: I have all my bikes cadded up on AutoCAD
to make sure they all fit the same way. You should see the variety of
tubing positions of all those bikes. But the saddles, BB's, and
handlebars are just about the same on all of them ('cept for the
5-degree forward tilt on the triathlon bike, of course).
>
>I'd be interested in knowing more about the geometry of your Habbie.
http://www.cynetfl.com/habanero/, though I understand the site is down
for the moment. Check back.
Here's the dimensions you won't see on the web page for my 58 cm
frame. The bike has a 106-cm wheelbase, which is looooong, and a
generous 9 cm of trail (the trail is a full centimeter longer than the
Trek, which is one reason it loves a straight line). The distance from
the tip of the saddle back to the rear axle is the same as on the
Trek, but it is 6 cm longer to the front axle (hence the difference in
stem and top tube). It uses a straight stem instead of a sloping stem,
and the saddle-to-bar drop is thankfully a bit less, which resolves
the Controversy (113 mm in my case--not that much, and 2 cm less than
the Trek). The BB is a centimeter higher than the Trek, which is part
of why it has a longer head tube.
Now, I've been open about the dimensions of the bike, and I don't
really think Mark Hickey needs for me to defend the decisions he's
made in the design. Let's just say that these work very well for me,
and I know very well what I wanted. So, if you want to throw darts,
throw them at me and not at Mark, because I chose the frame size I
wanted after talking with him and after cadding it up.
Rick "I can't define good fit, but I know it when I see it" Denney
Mike Bundy
appear, but I well take the point about you being happy with the bike
that fits you. I don't have a "boardman-back" either but I find that my
P2 -- with it's lower top-tube -- happens to fit *ME* like a glove. I
can ride this thing without any issues of knee clearance -- but I'm
quite aware that my preferred position could well prove to be someone
else's worst nightmare.
The value of this, to *ME*, would have remained an unknown (actually I
was totally ignorant of it) prior to my P2. Now I appreciate it -- I
don't use any spacers on my P2 and it works for *ME* -- but I suspect it
wouldn't be of much value to Jurgen... with that infamous bad back.
The C'dale had the option to use a lower top-tube (shorter head-tube)
but chose not to -- but I guess that's just part of what makes the
C'dale different.
The point being, that if I'd chosen a C'dale I would never have been
able to achieve the position that I now use -- however, with spacers, I
still have the *option* to use a higher position with the P2. I would
never have known I could ride at this height without having the option
to do so, but I guess it's fair to say that if I couldn't ride that low,
then the option would be wasted on me -- horses for courses?
-- MB.
Rick Denney wrote in message
<60983536F8E90D1A.F9A0C1A1...@library-proxy.airnew
s.net>...
cog...@grecc1.ab.umd.edu
> The Thigh-Rib Controversy is not because of the compressed hip angle.
> The converted road bike and the Habanero both had effective 78-degree
> seat tubes. The problem is congenital spondylolisthesis, which is an
> anterior displacement of the lower spine of about one cm, plus a round
> cross-section through the rib cage instead of the Surfer-Dude flat
> configuration. The little bit of belly we won't discuss, at least not
> if you want me to stay civil.
Well, I'm pretty skinny, and I don't know about my spine...however, I am very
"round chested", to the point that I'm almost as deep as I am wide at the
lower end of my rib cage, and my knees also tend to chest when in an extreme
aero position. But I don't really see that as a problem...all you have to do
is move the seat a bit further forward, and/or arch your back (I've never
seen any data showing the the profile - vs the angle - of your back has any
effect on drag), and contact is avoided.
To me the limit of how low you can go is not knee/rib contact, or comfort,
but power. Although you do adapt physiologically to a low position (it has
been shown that the relationship between leg extension force and hip angle is
shifted to a more acute angle in cyclists and speedskaters vs. e.g.,
runners), everybody eventually runs into a limit at which sustainable power
begins to decline. Interestingly, in my case this seems to be at about the
point that my knees just brush my chest - this may be the result of years and
years of riding road bikes with ~73 degree seat tube angles, i.e., I've
adapted to the limits of the position I routinely use.
> Here's the dimensions you won't see on the web page for my 58 cm
> frame. The bike has a 106-cm wheelbase, which is looooong, and a
> generous 9 cm of trail (the trail is a full centimeter longer than the
> Trek, which is one reason it loves a straight line).
I like the idea of a long wheelbase and front center on a TT/triathlon bike -
my 54 cm Hooker has a wheelbase of (IIRC) 103 cm. However, are you sure about
that trail measurement of 9 cm? That's a lot more than 1 cm greater than the
5-5.5 cm typically found on a bike. Indeed, I can't imagine even trying to
ride a bike w/ 9 cm of trail - the steering response would be so slow that
you'd have a hard time staying upright...
Andrew Coggan
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Rick Denney
<mbu...@OzEmail.com.au> wrote:
> horses for courses?
>
Precisely.
Cervelo Cycles
Rick Denney wrote:
> That, and the switch to a true 78-degree seat tube, tells me that
> they've been going to school on the competition.
Talking about going to school on the competition, when I checked the C'dale
geometry the other day, I noticed they had a "minimum saddle height" that one
could obtain with their bikes due to the slightly extended seattube. What a
surprise to find that their wording to explain this feature was identical to
the text in our information packs, complete with using a Flite saddle for the
comparison. Quite a coincidence.
Anyway, now that Dan and I have shared our views on these geometries, maybe Joe
Montgomery would like to do the same?
Gerard.
Rick Denney
>
>Well, I'm pretty skinny, and I don't know about my spine...however, I am very
>"round chested", to the point that I'm almost as deep as I am wide at the
>lower end of my rib cage, and my knees also tend to chest when in an extreme
>aero position. But I don't really see that as a problem...all you have to do
>is move the seat a bit further forward, and/or arch your back (I've never
>seen any data showing the the profile - vs the angle - of your back has any
>effect on drag), and contact is avoided.
Arching my back was my solution when I was riding the Trek. But I was
not comfortable, and could not maintain an aero position for long
periods. If I tried, I ended up with a terrible backache bordering on
spasms. It's one of the main things I was trying to solve with a new
bike. And it is one of the main reasons I went to the forward position
in the first place.
[Thank you for not mentioning that other possible interference that I
have and you don't.]
I want to address an important point, though, that is reflected in
your comments. You are going for the maximum aero position on your
Hooker, and you like to ride time trials. You know better than almost
anybody what's aero and what ain't, so you know how to dial yourself
into that goal.
I have a little bit different objective. I'm going for a *reasonably*
aero position that still maintains sufficient comfort for really long
rides. I'm old and crotchity, and I may be more picky about comfort
than you, heh, heh. The time I would gain by being as aero as possible
might be the difference between enjoying the run and suffering through
it. And I need all the help I can get in the run.
>
>To me the limit of how low you can go is not knee/rib contact, or comfort,
>but power. Although you do adapt physiologically to a low position (it has
>been shown that the relationship between leg extension force and hip angle is
>shifted to a more acute angle in cyclists and speedskaters vs. e.g.,
>runners), everybody eventually runs into a limit at which sustainable power
>begins to decline. Interestingly, in my case this seems to be at about the
>point that my knees just brush my chest - this may be the result of years and
>years of riding road bikes with ~73 degree seat tube angles, i.e., I've
>adapted to the limits of the position I routinely use.
Good points. I suspect that in my case the Controversy is invoked
sooner than power problems, though, and maybe because of that factor
that you graciously avoided mentioning.
>
>> Here's the dimensions you won't see on the web page for my 58 cm
>> frame. The bike has a 106-cm wheelbase, which is looooong, and a
>> generous 9 cm of trail (the trail is a full centimeter longer than the
>> Trek, which is one reason it loves a straight line).
>
>I like the idea of a long wheelbase and front center on a TT/triathlon bike -
>my 54 cm Hooker has a wheelbase of (IIRC) 103 cm. However, are you sure about
>that trail measurement of 9 cm? That's a lot more than 1 cm greater than the
>5-5.5 cm typically found on a bike. Indeed, I can't imagine even trying to
>ride a bike w/ 9 cm of trail - the steering response would be so slow that
>you'd have a hard time staying upright...
I'm going on measurements that I jotted down on a sketch that I made
when I was transfering parts from the Trek to the Habanero (which I
did in the back room here at the office before the house was
finished). The number I have for the Trek is "82" and for the Habanero
"90." I remember holding a straightedge to the head tube, and making a
mark on the floor, and measuring from the mark to where a plumb bob
reached the floor from the front axle. But I agree that these numbers
are too big, and I'm sure I drew my sketch wrong, or the numbers don't
mean what I think they mean. I'm also pretty sure that the trail is
about a centimeter longer on the Habanero. I'll check tonight. The
Habbie is not particularly weird in this department, and gets the
longer trail through frame geometry--the fork is a standard Kestrel.
Rick "Something doesn't compute--where's my tape measure?" Denney
cog...@grecc1.ab.umd.edu
> I want to address an important point, though, that is reflected in
> your comments. You are going for the maximum aero position on your
> Hooker, and you like to ride time trials.
>
> I have a little bit different objective. I'm going for a *reasonably*
> aero position that still maintains sufficient comfort for really long
> rides. I'm old and crotchity, and I may be more picky about comfort
> than you, heh, heh.
As you (or somebody else in this thread) said, "horses for courses". I
certainly don't disagree with that. I wonder, though, if could you be more
aero yet still be comfortable if you went to an even more forward, and lower,
position?
> I'm going on measurements that I jotted down on a sketch that I made
> when I was transfering parts from the Trek to the Habanero (which I
> did in the back room here at the office before the house was
> finished). The number I have for the Trek is "82" and for the Habanero
> "90." I remember holding a straightedge to the head tube, and making a
> mark on the floor, and measuring from the mark to where a plumb bob
> reached the floor from the front axle. But I agree that these numbers
> are too big, and I'm sure I drew my sketch wrong, or the numbers don't
> mean what I think they mean. I'm also pretty sure that the trail is
> about a centimeter longer on the Habanero. I'll check tonight. The
> Habbie is not particularly weird in this department, and gets the
> longer trail through frame geometry--the fork is a standard Kestrel.
Maybe the straightedge wasn't truly straight? ;-)
I've never actually tried to measure the trail of a bike, but have simply
relied on calculating it from head tube angle, fork offset, and wheel
diameter. What impresses me the most in this area is how very small
differences in trail have such a big effect on a bike handles, and also how
much you can come to prefer a certain trail. Personally, I like bikes w/ a
little more than 5.5 cm of trail, and find bikes like my wife's Kestrel
(which has, IIRC, 5.2 cm) too "quick" for my tastes. Indeed, this was an
important consideration when I was shopping for a road bike recently - I
considered a number of possibilities, but rejected many because they less
trail than what I've grown so used to over the years...
Dan Empfield
> As you (or somebody else in this thread) said, "horses for courses".
an affirmation of our unanimity of thought.
qr (somebody else in this thread) man
Rick Denney
>Rick Denney wrote:
>
>> I want to address an important point, though, that is reflected in
>> your comments. You are going for the maximum aero position on your
>> Hooker, and you like to ride time trials.
>>
>> I have a little bit different objective. I'm going for a *reasonably*
>> aero position that still maintains sufficient comfort for really long
>> rides. I'm old and crotchity, and I may be more picky about comfort
>> than you, heh, heh.
>
>As you (or somebody else in this thread) said, "horses for courses". I
>certainly don't disagree with that. I wonder, though, if could you be more
>aero yet still be comfortable if you went to an even more forward, and lower,
>position?
Possibly. But my bike is already 78 degrees. Going more forward would
be difficult. And I'm not sure my neck bends far enough. And isn't
there a rule (I'm really vague on this) that limits the saddle
position with respect to the bottom bracket? Or am I confusing this
with UCI road racing rules?
>
>> I'm going on measurements that I jotted down on a sketch that I made
>> when I was transfering parts from the Trek to the Habanero (which I
>> did in the back room here at the office before the house was
>> finished). The number I have for the Trek is "82" and for the Habanero
>> "90." I remember holding a straightedge to the head tube, and making a
>> mark on the floor, and measuring from the mark to where a plumb bob
>> reached the floor from the front axle. But I agree that these numbers
>> are too big, and I'm sure I drew my sketch wrong, or the numbers don't
>> mean what I think they mean. I'm also pretty sure that the trail is
>> about a centimeter longer on the Habanero. I'll check tonight. The
>> Habbie is not particularly weird in this department, and gets the
>> longer trail through frame geometry--the fork is a standard Kestrel.
>
>Maybe the straightedge wasn't truly straight? ;-)
Could be. I measured it again this morning, though the measurement
method was not one I'm proud of--with a measurement error that I'd
estimate in the +/- 1 cm range. My Habanero had 7 cm of trail, my
Cannondale touring bike 6 cml, my track bike (with a road fork) 5.5
cm, and my vintage Moore 6.5 cm of trail. I didn't measure the
Merckx--it was in the other room. So, if I'm consistent at least, then
the Habbie runs a bit long on trail. When I get back from Denver, I'll
do it right.
>
>I've never actually tried to measure the trail of a bike, but have simply
>relied on calculating it from head tube angle, fork offset, and wheel
>diameter. What impresses me the most in this area is how very small
>differences in trail have such a big effect on a bike handles, and also how
>much you can come to prefer a certain trail. Personally, I like bikes w/ a
>little more than 5.5 cm of trail, and find bikes like my wife's Kestrel
>(which has, IIRC, 5.2 cm) too "quick" for my tastes. Indeed, this was an
>important consideration when I was shopping for a road bike recently - I
>considered a number of possibilities, but rejected many because they less
>trail than what I've grown so used to over the years...
These values are consistent with my measurements, so maybe I got it
right this time.
Rick "Not through with this topic" Denney
cog...@grecc1.ab.umd.edu
> I wrote:
>
> > As you (or somebody else in this thread) said, "horses for courses".
>
> an affirmation of our unanimity of thought.
In a relative sense, maybe. But in an absolute sense, no - the position you
recommend (as exemplified by the formula on your website, the .jpg images you
posted there some time ago, and that used by the QR-sponsored athletes I saw
tested at the wind tunnel) is definitely higher than what I would say is a
good starting point. Indeed, if I set my TT bike up using your quideline my
shoulders end up at about the same height above my hips as when I'm on the
drop bars of my road bike...
pso...@hidro1.ist.utl.pt
cog...@grecc1.ab.umd.edu wrote:
>
> In a relative sense, maybe. But in an absolute sense, no - the position you
> recommend (as exemplified by the formula on your website, the .jpg images you
> posted there some time ago, and that used by the QR-sponsored athletes I saw
> tested at the wind tunnel) is definitely higher than what I would say is a
> good starting point. Indeed, if I set my TT bike up using your quideline my
> shoulders end up at about the same height above my hips as when I'm on the
> drop bars of my road bike...
Did you ever get to post a picture of you and your super-low, radical aero
position? I've seen it mentioned many times, but I don't recall you posting a
pic of it.
Thanks
Paulo
Cervelo Cycles
Rick Denney wrote:
> SNIP And isn't
> there a rule (I'm really vague on this) that limits the saddle
> position with respect to the bottom bracket? Or am I confusing this
> with UCI road racing rules?
>
The UCI rules stipulates that the tip of the saddle has to be 5cm behind the
center of the bb, the triathlon rules allow the tip of the saddle to be 5cm ahead
of the center of the bb
cog...@grecc1.ab.umd.edu
my ISP's web page hosting service. There are, though, lots and lots of
pictures on the 'net and in magazines of riders w/ good aero positions - in
comparison to some (e.g., the pictures of Colby Pierce and Eric Wohlberg at
the Hed and Cervelo websites, respectively), my position doesn't look all
that radical. My shoulders are about as low, but I'm taller w/ a longer torso
and prefer a more extended arm position, and so don't give the same
impression of being curled up into a fetal position. If, however, I swing my
arms back closer to my knees w/o lowering my shoulders, my knee at the top of
the pedal stroke hits the middle-back of my triceps, which is about how high
these fellows (and Boardman) ride.
Paulo wrote:
> Did you ever get to post a picture of you and your super-low, radical aero
> position? I've seen it mentioned many times, but I don't recall you posting a
> pic of it.
Andrew Coggan
Stacy Hills
First I'll apologize for snipping from 2 of your(Gerard's) messages that are
a few days old. So old I had to grab them from dejanews.
I don't know who Joe Montgomery is but I'm guessing, from the context, that
he's a Cannondale engineer? Before I dig in, let me say that I do own 3
Cannondales, one of them being an older 650c, 75 degree TT bike. However, I
don't think this necessarily biases my opinion because my post isn't about
Cannondale, but about Cervelo & QR.
You are all(Dan, Gerard, Rick, Andy) bandying about your opinions including
whether the 'dale head tube is short enough and whether the top tube slopes
down enough compared to your bikes. Now, anyone can go to the Cannondale
website and examine every measurement that you guys have been discussing
with the exception being head tube length. Gerard, at least you've posted
head tube and top tube lengths, but nothing regarding your vaunted top tube
height. Dan has nothing regarding geometry on his website other than a
statement about how he invented it(triathlon geometry, that is). I find it
difficult to follow your discussion without being able to quantify and
compare the dimensions you deem important. This may not be r.b.t. but it is
a technical sort of discussion, no? As it currently stands, this discussion
is not much more than you fellas saying that Cannondale hasn't got it quite
right, but you're not telling us what you think "right" is. Is this really
a discussion of the merits of various geometrys, or is it just an
opportunity for you lads to sell some bikes? I might not say that so
rudely, except this is not the first time this particular topic has been
"discussed".
I'd add Habanero in this barrage too, but I can't access Mark's website to
see whether he includes all the numbers. Not to mention, Mark hasn't issued
an opinion in this thread on anything other than frame materials.
Give us your numbers, please. Maybe a measurement to include, from what I'm
gathering you fellas deem as important, would be the height of the top of
the head tube. Then, for example, assuming you give a few other dimensions
a prospective customer could back out just how large a seat-to-bar distance
he could expect on your bikes. We can already figure this
number(approximately) from Cannondale's web page.
In short, put up or shut up.
Stacy Hills
Reston, VA
Cervelo Cycles <intern...@cervelo.com> wrote...
Rick Denney wrote:
> > That, and the switch to a true 78-degree seat tube, tells me that
> > they've been going to school on the competition.
> Talking about going to school on the competition, when I checked the
C'dale
> geometry the other day, I noticed they had a "minimum saddle height" that
one
> could obtain with their bikes due to the slightly extended seattube. What
a
> surprise to find that their wording to explain this feature was identical
to
> the text in our information packs, complete with using a Flite saddle for
the
> comparison. Quite a coincidence.
>
> Anyway, now that Dan and I have shared our views on these geometries,
maybe > Joe
> Montgomery would like to do the same?
>
> Gerard.
And in an earlier message:
Dan Empfield
<shi...@vctinc.com> wrote:
> Dan has nothing regarding geometry on his website other than a
> statement about how he invented it(triathlon geometry, that is).
http://www.rooworld.com/geometry.html
this includes head tube lengths.
> As it currently stands, this discussion
> is not much more than you fellas saying that Cannondale hasn't got it quite
> right, but you're not telling us what you think "right" is.
by the way, aegis doesn't have it quite right either.
> Is this really
> a discussion of the merits of various geometrys, or is it just an
> opportunity for you lads to sell some bikes?
i suspect in discussing the merits of various geometries, and other
elements of bike design, gerard & i hope that you will see the difference
between companies interested only in the market opportunities and
realities of multi-sport, as opposed to those also interested in you, your
sport, the well being of your sport, and the well being of the multi-sport
industry. we hope, in the long run, that this understanding will lead you
to opt for our bikes, or kestrel's bikes, or somebody's bikes that are
made for triathletes, by triathletes, or at least by students of
triathlon.
> I don't know who Joe Montgomery is but I'm guessing, from the context, that
> he's a Cannondale engineer?
joe montgomery is the founder and president of c'dale, a very fine
performer in the bike industry, with whom my division does business, both
in buying and selling. i have the greatest respect and admiration for
c'dale, their products, and their way of business. but their head tubes
are too tall in their tri bikes.
> In short, put up or shut up.
i think somebody from-- or familiar with-- c'dale's tri bikes should get
online and defend the way they build them. in short, they should put up,
or their defenders should shut up.
qrman
Dan Empfield
>> but you're not telling us what you think "right" is.
in my previous answer to this post, maybe i should have expounded on this
particular statement of stacy's. i think what gerard and i (and some
others, like rick denney, who do not run bike companies) contend is that
it's all well and good to say that your bike has a steep seat angle and
26" wheels. but there are other elements of tri bike design that need
attention. among them:
1. proper weight displacement front and rear, which means pretty
carefully determining chainstay length and front/center (distance from the
bb axle to front axle), and maybe even a better measure is to draw a line
perpendicular to the ground from any point on the saddle, and measure the
distance, parallel to the ground, from this line to the front axle, and to
the rear axle. i say this because chainstay and front/center disregard
where your butt is, hence where your weight is, in relation to the front
and rear axle.
2. the way the front derailleur shifts; i.,e., if you put a band style FD
on a 78 degree bike you're asking for all kinds of trouble, and as a bike
maker you must account for this.
3,4,5,6: a whole bunch of items i won't go into that revolve around fit,
ergonomics, handing, etc., and require lots of knowledge about exactly how
tri bikes should work, and these things are different than for road bikes;
so making assumptions about head angle, rake, and the resulting trail, top
tube and cockpit lengths, bar choices and positions, etc., from a road
bike builder's perspective is going to yield a crummy tri bike.
7. the one particular issue that is germaine to this thread, and which
stacy asks about, is head tube height. how high it is off the ground is
of no consequence. what matters is where the top of the head tube is in
relation to where the top of your saddle is going to be when you build the
frame into a complete bike. this is important because a decent aero
position requires a fairly low armrest position in relation to the saddle
(explained exhaustively on our website), and if the headtube top is not
low enough, you're going to have a hard time getting into a low enough
position without something like a track stem. if you furthermore make the
bike with a top tube too long, there's no stem known to man that will get
you where you need to be.
as to what is "right", www.rooworld.com/geometry.html defines my idea of
"right", or else we'd be making our headtubes some other dimension.
"wrong" is something than varies greatly from our geometry, because it
won't work well. therefore, cervelos and qr's have fairly similar
headtube tops, with the detail and reasoning on each of our websites that
backup our views.
so why would some bike companies make bikes with their headtubes too
tall? two reasons, either they just don't understand the problem and the
issue; or they use top and down tubes with major diameters perpendicular
to the ground (like aero tubes), with these diameters being quite large,
and such makers are unable to weld the tubes onto a small enough
headtube. or, alternatively, they don't know how, or choose not, to
compound mitre the tubes to get them onto a smaller headtube.
gerard DOES use such tubes that make in problematic to use a small enough
head tube, esp on smaller bikes, and yet he IS able to make it work.
gerard's point, although he won't come out and say it, is that some people
are lulled into thinking that some bikes that use aero tubes are cheaper
than a P2, and are otherwise similar enough to a P2 to buy instead of a
P2. gerard's P2 is a legitimate aero bike, THE ONLY double diamond bike
in existance that can legitimately claim to be (somewhat) more aero than a
round tube bike, so far as i am concerned. EVERY OTHER such bike made
fails-- in my opinion, based mostly on the large width of their minor
diameters-- to get the job done aerodynamically. and so when you buy such
bikes, thinking they're more aero, you end up buying worse bikes then when
you buy round tubed bikes. gerard won't come out and say that, for
obvious reasons of sounding catty and such, so i'll sound catty for him.
that's a little off the subject of headtube tops, but to bring it full
circle, you therefore have bikes that have headtube tops that are too
high, which is a result of using tubes which are fakey aero that do not
allow the use of headtubes of a proper size.
lest you think i'm cozying up to gerard, i've got some problems with how
he builds his bikes, and i personally think the eyre is-- or is bordering
on-- fakey aero. but if you're going to buy fakey aero, gerard makes the
best fakey aero money can buy IMHO. i believe the P2 is really
legitimately aero vs other double diamond bikes, including our bikes (our
redstone may be the equal or better than the P2 at certain higher speeds,
but seems quite mortal at slower speeds, so i'll not claim that even the
redstone unequivocally outduels the P2 aerodynamically).
qrman
Andrew Coggan
(much stuff about "tri-bike" design snipped)
> P2. gerard's P2 is a legitimate aero bike, THE ONLY double diamond bike
> in existance that can legitimately claim to be (somewhat) more aero than a
> round tube bike, so far as i am concerned.
There are a number of bikes that closely resemble the P2 (or that the P2
closely resembles), for the simple reason that form follows function. It
is true that many are no longer still in production, but examples
routinely show up on rec.bicycles.marketplace. And, there's always the
new double-diamond carbon fiber Hotta.
> lest you think i'm cozying up to gerard, i've got some problems with how
> he builds his bikes, and i personally think the eyre is-- or is bordering
> on-- fakey aero.
!!!!!!!
> i believe the P2 is really
> legitimately aero vs other double diamond bikes, including our bikes (our
> redstone may be the equal or better than the P2 at certain higher speeds,
> but seems quite mortal at slower speeds, so i'll not claim that even the
> redstone unequivocally outduels the P2 aerodynamically).
How is this possible? The reason that people have settled on testing at
only one wind velocity (i.e., 30 mph) is because testing at multiple
velocities has demonstrated that the coefficient of drag of bicycles is
a constant (as one would expect). Are you saying that the Redstone
experiences some sort of flow transition at higher velocities?
Having seen wind tunnel test results for a number of different bicycles,
including some featuring "winged keels", etc., I would be surprised if
the Redstone had lower drag than the P2 at ANY velocity, at least w/ a
rider aboard. I'm not saying that it isn't possible, just that it isn't
the result I would expect based on the data I've seen (which is why wind
tunnel testing is so useful).
Dan Empfield
> > i believe the P2 is really
> > legitimately aero vs other double diamond bikes, including our bikes (our
> > redstone may be the equal or better than the P2 at certain higher speeds,
> > but seems quite mortal at slower speeds, so i'll not claim that even the
> > redstone unequivocally outduels the P2 aerodynamically).
>
> How is this possible? [inquiring about aero efficiency being different
at different speeds].
i could very well be wrong, there could be another simple explanation.
this bike has only been roll-down tested. it just doesn't outdo our other
bikes at slower speeds, but is faster at higher speeds on roll-down tests,
esp when you get into the mid-20's and up.
it could simply be a function of wind resistance being so much more
apparent at higher speeds. it is just very obvious to me how mortal this
bike is at, say 18mph. maybe all aero bikes are this way, andy, maybe you
have some insight here.
> How is this possible? The reason that people have settled on testing at
> only one wind velocity (i.e., 30 mph) is because testing at multiple
> velocities has demonstrated that the coefficient of drag of bicycles is
> a constant (as one would expect).
one reason bikes get tested at 30mph, probably the main reason, is that if
you test them at slower speeds, the difference between bikes, wheels,
etc., converge, and if you were to test at, say, 22mph, there would be
virtually no meaningful difference between most of these products. if
you're going to ask me for test results to support this, i have none to
point to, and i doubt if you can find any either, simply because of the
knowledge of this phenomenon by those who perform tests. at least this is
the reason they give me when i ask them why they don't test at slower
speeds.
i guess my previous explanation could lead you to believe i'm saying that
the coefficient of drag of the redstone with the rider aboard changes vs
other bikes. i do not know that this can or can't happen, and if you say
that it has been demonstrated beyond a reasonable doubt that it can't
happen i defer to your knowledge & judgement.
qrman
Andrew Coggan
> i could very well be wrong, there could be another simple explanation.
> this bike has only been roll-down tested. it just doesn't outdo our other
> bikes at slower speeds, but is faster at higher speeds on roll-down tests,
> esp when you get into the mid-20's and up.
>
> it could simply be a function of wind resistance being so much more
> apparent at higher speeds. it is just very obvious to me how mortal this
> bike is at, say 18mph. maybe all aero bikes are this way, andy, maybe you
> have some insight here.
If you model the power requirements of cycling using a simple
exponential function (thus ignoring e.g., rolling resistance, which
scales linearly w/ velocity), you get an exponent of around 2.7 or so,
i.e., less than the 3 one would expect. Similarly, you have to account
for rolling resistance when trying to determine aerodynamic drag from
coast-down tests - otherwise you get an apparent velocity effect, as you
are seeing. In fact, though, when people like Chet Kyle have tested
bikes at a whole range of velocities, the relationship between drag and
velocity^2 has been nicely described by a linear function, indicating
that no flow transition occurs, and that testing at one velocity is
sufficient to determine the bike's drag characteristics (i.e., the drag
area, or CdA).
> one reason bikes get tested at 30mph, probably the main reason, is that if
> you test them at slower speeds, the difference between bikes, wheels,
> etc., converge, and if you were to test at, say, 22mph, there would be
> virtually no meaningful difference between most of these products.
That is my understanding as well - 30 mph was *eventually* chosen as a
defacto standard as a) it was fast enough to make differences between
bikes, etc., above the inherent noise in the measurements, yet b) slow
enough that it was within a (quasi) realistic range. However, just
because you can't *detect* a difference at slower speeds doesn't mean
that there isn't one - it just means that it isn't big enough to be
detected against other sources of variation. While people are often
tempted to interpret this as meaning that aerodynamics aren't important
for the average athlete, the fact is that such individuals actually will
actually save the MOST time (in an absolute sense) by choosing a
position or equipment that has e.g., 5% less drag.
> i guess my previous explanation could lead you to believe i'm saying that
> the coefficient of drag of the redstone with the rider aboard changes vs
> other bikes. i do not know that this can or can't happen, and if you say
> that it has been demonstrated beyond a reasonable doubt that it can't
> happen i defer to your knowledge & judgement.
No, I didn't interpret it that way, since I assumed that you were
talking about wind tunnel testing sans rider, not coast-down testing w/
a rider aboard. But speaking of w/ vs w/o rider comparisons - why is
that you describe the Eyre has having "fakey aerodynamics", yet are
apparently impressed by the P2 (and obviously your own Redstone)? From
the b.b. forward, the only difference (AFAIK) between the P2 and the
Eyre is that the former has internal cables whereas the latter has
exposed, bare cables. As I understand things, this difference alone is
unlikely to have a major effect on drag. Thus, any difference between
the P2 and the Eyre would presumably relate to the aero seattube and
rear wheel cut-out of the former - yet since these design features are
towards the back of the bike and between the rider's whirling legs. I
would expect that much of their benefit is lost when you test w/ a rider
aboard. IOW, if you tested a round-tubed bike (e.g., the QR Kilo) vs an
Eyre vs a P2, all w/ the same rider aboard, I would expect that the Eyre
would perform more like the P2 than the Kilo - yet you describe is as
having "fakey aerodynamics"?
Mark Hickey
>I'd add Habanero in this barrage too, but I can't access Mark's website to
>see whether he includes all the numbers. Not to mention, Mark hasn't issued
>an opinion in this thread on anything other than frame materials.
I woulda chimed in, but I'm on the road, and pretty much out of touch
for the last few days. My ISP is going through some BIG problems, and
has promised to get my email and site back up... days ago. Sigh....
It's also taken down my access to email, though I've set up a
temporary account at habb...@yahoo.com
On the whole "length of the head tube thing".... It's kinda hard for
me to make a real comparison with QR's geometry, since there doesn't
appear to be any reference on their website as to whether the bikes
are measured center to top or center to center.
The only thing that will impact the "drop" from the saddle to the bars
is the difference in height of the top of the top tube and the top of
the seat tube. QR has chosen to increase the seat tube length above
the top tube to achieve this. I've also subscribed to this approach,
and my frames have approx 1" (2.5cm for you Yurrupeans) of reinforced
seatpost extention above the top of the seat tube. That's obviously
less than the QR, which appears to have maybe twice that much (don't
see a spec for that either).
But if you have two bikes with horizontal top tubes, and that are
measured the same way (i.e. c-c or c-t), the length of the head tube
becomes a virtual non-issue. You have to have a certain amount of HT
extention above the top tube, and that's not gonna vary by more than a
few mm's between manufacturers. Where the BOTTOM of the HT is doesn't
mean squat as to fit, but is simply a matter of the fork you use (i.e.
the Terry "funny bikes" have REAL long head tubes, but that doesn't
affect the saddle to bar drop). That means that unless someone has a
REAL long HT extention above, or sinks the top of the HTinto the TT,
the length isn't going to matter much.
But, I have to wonder... if getting the bars low is the holy grail of
setting up tri-bikes, why oh why do all the bikes on the QR website
come equipped with 90 degree stems? The end result will be certainly
no lower than a "normal" frame equipped with a roadie stem, and there
is no inherent disadvantage or advantage to achieving the same
position either way. The bikes pictured also seem to have about 1" of
spacers under the (threadless) stems, which makes the drop even less.
Looking for the answer in the total height of the top of the head tube
is pointless as well, since it's all relative to the the height of the
bottom bracket (or inversely relative to the bottom bracket drop, but
that sounds too complicated).
Hopefully this will shed some light on the subject, without throwing
fuel on any fires.
Mark Hickey
Habanero Cycles
http://www.cynetfl.com/habanero - someday
Home of the $695 ti frame
Stacy Hills
Dan Empfield <QR...@rooworld.com> wrote in message
news:QRman-20039...@qrman.cts.com...
> > a discussion of the merits of various geometrys, or is it just an
> > opportunity for you lads to sell some bikes?
>
> i suspect in discussing the merits of various geometries, and other
> elements of bike design, gerard & i hope that you will see the difference
> between companies interested only in the market opportunities and
> realities of multi-sport, as opposed to those also interested in you, your
> sport, the well being of your sport, and the well being of the multi-sport
> industry. we hope, in the long run, that this understanding will lead you
> to opt for our bikes, or kestrel's bikes, or somebody's bikes that are
> made for triathletes, by triathletes, or at least by students of
> triathlon.
>
Good grief, Dan. You make it sound as if you're David and Cannondale and
the other big bike companies are Goliath and the Philistines overrunning the
motherland.
>
> > In short, put up or shut up.
>
> i think somebody from-- or familiar with-- c'dale's tri bikes should get
> online and defend the way they build them. in short, they should put up,
> or their defenders should shut up.
>
Okay, I was rude so I had that coming. But, I want to re-stress that I'm
not necessarily a Cannondale defender. Yes, I have a 'dale TT bike, but I
don't think it fits me well. If I could wind the clock back 4 years to when
I bought it, I'd buy something different. That's why I'm jumping into this
thread. I'd like to know more about what you and Gerard consider proper tri
geometry and fit.
The point I was trying to make is that the conversation regarding geometry
that you and Gerard are engaged in before us is a bit too vague to follow
unless you give us more to go on. Just saying Cannondale's head tube is too
long does us little good unless we have an idea of what you think the right
length is. Sure, you guys know what numbers you mean, but if you're trying
to educate us then you've got to let us in on them too. Are we talking a
couple of centimeters or a couple of inches. If its the former then I'll be
on my way, but if its the latter then I'd like to hear more on the subject.
Do tell.
Stacy Hills
Reston, VA
Stacy Hills
Mark Hickey <mhi...@cynetfl.com> wrote in message
news:36f5541f...@news.nuri.net...
> "Stacy Hills" <shi...@vctinc.com> wrote:
>
<--Mark's ISP woes and interesting head tube discussion snipped-->
>
> Looking for the answer in the total height of the top of the head tube
> is pointless as well, since it's all relative to the the height of the
> bottom bracket (or inversely relative to the bottom bracket drop, but
> that sounds too complicated).
>
Well, that's assuming a horizontal top tube. The reason I requested this
number is that Gerard made a statement about Cannondale's top tube not
really being sloped. I didn't know whether this was to imply that his top
tubes do slope so I figured I'd take it as yes they do. In which case I'd
go the extra mathematical mile and take this drop into account when figuring
the seat to bar drop.
> Hopefully this will shed some light on the subject, without throwing
> fuel on any fires.
>
I quite like the point about the 90 degree stem and the spacers. Thanks for
pointing that out.
I also like the looks of Denney's TT bike(Habanero). We're close to the
same size so I'm hoping he'll let me give it a test ride one of these Spring
days.
Stacy Hills
Reston, VA
Dan Empfield
> But speaking of w/ vs w/o rider comparisons - why is
> that you describe the Eyre has having "fakey aerodynamics", yet are
> apparently impressed by the P2 (and obviously your own Redstone)? From
> the b.b. forward, the only difference (AFAIK) between the P2 and the
> Eyre is that the former has internal cables whereas the latter has
> exposed, bare cables. As I understand things, this difference alone is
> unlikely to have a major effect on drag. Thus, any difference between
> the P2 and the Eyre would presumably relate to the aero seattube and
> rear wheel cut-out of the former - yet since these design features are
> towards the back of the bike and between the rider's whirling legs. I
> would expect that much of their benefit is lost when you test w/ a rider
> aboard. IOW, if you tested a round-tubed bike (e.g., the QR Kilo) vs an
> Eyre vs a P2, all w/ the same rider aboard, I would expect that the Eyre
> would perform more like the P2 than the Kilo - yet you describe is as
> having "fakey aerodynamics"?
i now see the fundamental difference in our views, that you feel an aero
downtube is more efficacious than an aero seattube (even cervelo's
precisely and admirably done one). while in think that most "aero"
seattubes are bunk, i believe that one done correctly is a better way to
go than the aero downtube, for the various reasons you did not bring up:
1. the seattube, and things backward from it, are the last thing the wind
sees; the downtube is in the middle of the bike; i suspect that doing what
you can to reconnect the wind is the more important mission.
2. the other problem that occurs behind the seattube is the turbulence of
the rear wheel; an "aero" seattube has the triple mission of being aero
itself, reconnecting the wind behind the bike & rider, and fairing the
rear wheel; the downtube just sits there and looks pretty;
3. the seattube is much more perpendicular to the wind than the downtube,
which is already pointing in a line more parallel to the wind than
perpendicular.
4. the downtube usually carries the water bottle behind it, mitigating any
positive effect the aero aspect of the tube will have; the P2 has no water
bottle bosses here, which basically is gerard's statement that a water
bottle here is going to severely mess up what he's trying to achieve
aerodynamically (else why is such obvious needful items as water bottle
bosses removed?); the eyre, i believe, has the bosses (correct me if i'm
wrong), which is gerard's way of implicitly stating that the buyer of the
bike is less sophisticated, and so will probably not resort to ingenious
and convoluted ways to get his water placed elsewhere on the bike; thus
resulting in the aero catastrophe gerard so wants to avoid on the P2.
5. it has already been established that bikes that really are somewhat
more aero, however slightly, from standard frames, often-- or usually--
are so because of faired seattubes and either faired or missing
seatstays: the carbon monocoque softride (which has a decidedly unaero
downtube, yet still is reasonably aero, albeit the word i hear is that it
is mortal without a rear disc, but is very aero with one); lotus; hotta.
all these bikes use the seattube to fair the rear wheel, with only one set
of stays instead of two, except the softride, which doesn't fair the rear
wheel (hence the hubbub that the rear should be a disc), but this bike has
no seattube or stays to mess up the wind back there.
6. it has also already been established by the tester you and i are most
familiar with that one particular bike, very "hot" in the previous two or
three years, sporting simply an aero downtube and no other aero tube,
tested pretty much identically to round tubed bikes; the argument i've
heard in response is that this tube was not the "right" aero tube, but
really, the shape wasn't bad at all; the aero tube here just didn't work.
the very easiest thing to do is put an aero downtube in a bike. the
really hard thing to do is put an aero seattube in it, with corresponding
aero seatpost, and a nicely faired downtube that is sucked up pretty far
inside the seattube. that's really hard to do. but i think that's what
is likely to help the most, for reasons stated above. i think the eyre is
a fine, very rideable bike, but i think-- as everybody knows now thru my
droning on ad infinitum-- that if you are going to mess with the downtube
you'll pay, and the aero benefit you'll get is miniscule to non-existent
in return. if i wanted to buy a cervelo and aero-ness in the frame is of
such a concern, i'd save my money, opt for the P2, never leave the aero
position, and figure out what you're going to do with your water.
otherwise you just have to accept the fact that you're buying a cool
looking bike, with features that appear to work for their intended
purpose, but really don't. i'm reminded of when i travel in mexico, and i
love these 3rd class buses (usually green, schoolbus type buses) which the
drivers lovingly doll up. every now and then you'll find one with a fake
"scoop" on the hood, which is reminiscent of a performance enhancer, but
is really just there because it looks cool.
you're not swayed by, or in agreement with, the above reasoning, and i
accept that.
qrman
Cervelo Cycles
Stacy Hills wrote:SNIP
> Gerard, at least you've posted
> head tube and top tube lengths, but nothing regarding your vaunted top tube
> height.
This is not exactly correct. Headtube length and top tube height are two
measures of the exact same thing, so to list both is redundant and confusing. It
is like listing fork rake, trail and headtube angle, as two of these
measurements define the third.
We have chosen to list headtube length, as it is a lot easier for people to
measure and compare. It can be done on a frame, whereas for the top tube height
the customer can only measure it when the bike is built up.
Anyway, I would be interested in knowing what measurement people prefer,
headtube length or top tube height, as I would gladly convert the tables on our
website to reflect that preference.
> As it currently stands, this discussion
> is not much more than you fellas saying that Cannondale hasn't got it quite
> right, but you're not telling us what you think "right" is.
I think I have said it quite clearly, but I'll say it again. I think
Cannondale's headtubes are too long for most triathletes, in fact for almost
everybody. If Cannondale dealers are going to set-up their customers correctly
this year, the sales of Look Ergostems should be booming. Look is therefore
rated a strong buy :-). Unfortunately for Look, many Cannondale dealers don't
know that much about triahtlon positioning (which is not C'dale's fault, they
simply have so many dealers and most of them only understand mountainbike
positioning), so they will probably set people up in a position that is too high
in my opinion.
> Give us your numbers, please. Maybe a measurement to include, from what I'm
> gathering you fellas deem as important, would be the height of the top of
> the head tube. Then, for example, assuming you give a few other dimensions
> a prospective customer could back out just how large a seat-to-bar distance
> he could expect on your bikes. We can already figure this
> number(approximately) from Cannondale's web page.
I wonder how many people can figure it out from the C'dale website, but anyway,
thanks for the suggestion. It's the first time I have heard people were confused
by the way we list our geometry, but again, if more people would like to see the
information listed in this way, I will definitely change it.
> In short, put up or shut up.
I am not sure what triggered this response, but again, if there is some
consensus on rst, I will. I like reading and posting on rst, but there are
plenty of other things I could do that would be a lot more beneficial to our
company.
If you think the reason Dan and I post on rst is it renders sales, then why has
Cannondale, which by all accounts is the best marketed bike company today, not
used this opportunity?
Cervelo Cycles
Andrew Coggan wrote:
> Dan Empfield wrote:
>
> (much stuff about "tri-bike" design snipped)
>
> > P2. gerard's P2 is a legitimate aero bike, THE ONLY double diamond bike
> > in existance that can legitimately claim to be (somewhat) more aero than a
> > round tube bike, so far as i am concerned.
That's just my luck. Dan posts something like this, and the post doesn't appear
on my browser. I only get the part that Andrew didn't delete. Keep posting Dan
:-)
Dan Empfield
> On the whole "length of the head tube thing".... It's kinda hard for
> me to make a real comparison with QR's geometry, since there doesn't
> appear to be any reference on their website as to whether the bikes
> are measured center to top or center to center.
center to top. center to center would be kind of hard, since the center
is up to 10cm below the top with a dropped downtube.
> The only thing that will impact the "drop" from the saddle to the bars
> is the difference in height of the top of the top tube and the top of
> the seat tube. QR has chosen to increase the seat tube length above
> the top tube to achieve this. I've also subscribed to this approach,
> and my frames have approx 1" (2.5cm for you Yurrupeans) of reinforced
> seatpost extention above the top of the seat tube. That's obviously
> less than the QR, which appears to have maybe twice that much (don't
> see a spec for that either).
what would knowing that measurement do for you, mark? if there is some
good reason to have it i'll be glad to publish it. these measurements are
no secret we're trying to keep. we don't measure the distance from the
midpoint of the headtube to the rear brake bridge either, but i'm happy to
include it if anyone wants it.
> But if you have two bikes with horizontal top tubes, and that are
> measured the same way (i.e. c-c or c-t), the length of the head tube
> becomes a virtual non-issue.
THE important issue is where is the headtube top in relation to where the
saddle is going to be. the headtube bottom is fixed, you can't change
that. so where the top is, that is a function of the headtube length, and
in that sense the headtube length is really important. but i will grant
you this, the headtube length is just an extrapolated measure you can pick
on. what really matters is where is the headtube top in relation to the
saddle, per fixed frame size.
> But, I have to wonder... if getting the bars low is the holy grail of
> setting up tri-bikes, why oh why do all the bikes on the QR website
> come equipped with 90 degree stems?
they don't. they come with + or - 6 degrees and 25mm of stack, so that
you can have an extremely adjustable bike (the website only shows bikes
with + or - 6 degrees, you must be looking at someone else's site).
plenty of our customers start 5cm, 6cm, 7cm higher when the first get a
QR, and get lower gradually, as they become more accustomed to this style
of riding, are able to accommodate a lower position, and are set up and
re- set up by their LBS. we do show our site as having the stems in the
+6 degrees position, but for some of our pros even the -6 with no stack is
not low enough. riccitello has a -15 degree stem w/no stack on his PR.
> Looking for the answer in the total height of the top of the head tube
> is pointless as well, since it's all relative to the the height of the
> bottom bracket (or inversely relative to the bottom bracket drop, but
> that sounds too complicated).
okay, i'll bite. all bike makers agree that the lower you can make the BB
the better, for handling. the headtube bottom is fixed, and is higher for
your 700c bikes than for anybody's 650c. your BB is lower (BB drop
greater), surely, than 650c bikes, probably on average 6cm to 7cm of BB
drop to our average of 3.5cm to 4cm. so your saddle is lower to the
ground, and your headtube bottom is higher from the ground than a 650c
bike, to start with. that means that you'd need a considerably smaller
headtube just to get where you need to get to be the same as any 650c
bike. that's hard to do with 700c.
hey, maybe that's why time trial bikes have had a 650c front for the past
generation!
qrman
Stacy Hills
Cervelo Cycles <intern...@cervelo.com> wrote in message
news:36F664E6...@cervelo.com...
>
>
> Stacy Hills wrote:SNIP
>
> > Gerard, at least you've posted
> > head tube and top tube lengths, but nothing regarding your vaunted top
tube
> > height.
>
> This is not exactly correct. Headtube length and top tube height are two
> measures of the exact same thing, so to list both is redundant and
confusing. It
> is like listing fork rake, trail and headtube angle, as two of these
> measurements define the third.
>
> We have chosen to list headtube length, as it is a lot easier for people
to
> measure and compare. It can be done on a frame, whereas for the top tube
height
> the customer can only measure it when the bike is built up.
>
> Anyway, I would be interested in knowing what measurement people prefer,
> headtube length or top tube height, as I would gladly convert the tables
on our
> website to reflect that preference.
>
What I'm trying to discover is just what sort of seat to bar drop you feel
is adequate. That seems to be the number that you guys are focusing on.
That number is not availabe from the dimensions on your web site because you
measure the seat tube c-t rather than c-c. Even if you measured c-c, I can'
t tell if your top tube is sloped or horizontal, which would also need to be
taken into consideration.
> > As it currently stands, this discussion
> > is not much more than you fellas saying that Cannondale hasn't got it
quite
> > right, but you're not telling us what you think "right" is.
>
> I think I have said it quite clearly, but I'll say it again. I think
> Cannondale's headtubes are too long for most triathletes, in fact for
almost
> everybody. If Cannondale dealers are going to set-up their customers
correctly
> this year, the sales of Look Ergostems should be booming. Look is
therefore
> rated a strong buy :-). Unfortunately for Look, many Cannondale dealers
don't
> know that much about triahtlon positioning (which is not C'dale's fault,
they
> simply have so many dealers and most of them only understand mountainbike
> positioning), so they will probably set people up in a position that is
too high
> in my opinion.
>
Good grief, here we go 'round in circles... I think I'm getting dizzy. Too
long by how much? What should a typical triathlete look for in a seat to
bar vertical distance? If it varies with frame size then can we make it a
percentage of the top tube length? I really would like to understand what
your idea of proper fit is but this nebulous "too long" really gets me
nowhere.
> > Give us your numbers, please. Maybe a measurement to include, from what
I'm
> > gathering you fellas deem as important, would be the height of the top
of
> > the head tube. Then, for example, assuming you give a few other
dimensions
> > a prospective customer could back out just how large a seat-to-bar
distance
> > he could expect on your bikes. We can already figure this
> > number(approximately) from Cannondale's web page.
>
> I wonder how many people can figure it out from the C'dale website, but
anyway,
> thanks for the suggestion. It's the first time I have heard people were
confused
> by the way we list our geometry, but again, if more people would like to
see the
> information listed in this way, I will definitely change it.
>
Gimme a break, Gerard. Anybody with a rudimentary understanding of trig and
geometry ought to be able to figure out an approximation using some
dimensions from his current bike. Start with a saddle height(measured from
the BB) taken from another bike. I realize this may be off a little based
on the sort of bike, but it's a start. Work forward from the BB to the bar
making a couple of assumptions about the stem angle/length as well as the
stack height. Cannondale's spec page makes this possible(though difficult)
because though they also measure the seat tube c-t they list the stand-over
height of the top tube(can assume it's horizontal per your critique) and the
BB drop.
> > In short, put up or shut up.
>
I've snipped the rest of your post because my above statement was rude and
uncalled for. I'm sorry. I hope that you and Dan will accept my apology
and not ditch this thread for a little while longer. I'm not through
picking your brains.
It's just very frustrating to understand these discussions that you keep
holding before us without being able to assign some numbers to the
quantities that you deem important. I'm going to the QR road show this
weekend where I expect to find out a bit more about Dan's feelings on fit
via one of his minions.
Stacy Hills
Reston, VA
Dan Empfield
<shi...@vctinc.com> wrote:
> Good grief, Dan. You make it sound as if you're David and Cannondale and
> the other big bike companies are Goliath and the Philistines overrunning the
> motherland.
we i won't lose life & liberty. but in business terms, that is not
unlike what is happening in general in this industry. trek, c'dale,
specialized, etc., throughout road, MTB, and tri, sell plenty of bikes in
the $2k, $3k, and $4k range. unprecedented. they've done so in response
to pressure from smaller companies (probably no such thing as a trek oclv
if kestrel weren't there first; no c'dale tri bikes w/o qr, no aero tubing
w/o cervelo, the same can be said for analogs in road and MTB). plenty of
smaller guys either disappear or get sucked up into the borg (klein,
lemond, bontrager, yeti, nishiki, musing). in ten years, where will the
opening be in your LBS's open-to-buy if the majors have sucked all those
high-end dollars up upon pain of losing the exclusive? with the
open-to-buy dollars gone, LBS's won't be able to patronize the smaller
builders. this takes the pressure off the big guys to keep innovating,
and you get crappy bikes sold be LBS's that don't know what they're doing.
i'm not bitching or anything, we're adults, we can hold our own, i'm not
afraid of the competition. just the same, that IS the industry trend
right now.
> The point I was trying to make is that the conversation regarding geometry
> that you and Gerard are engaged in before us is a bit too vague to follow
> unless you give us more to go on. Just saying Cannondale's head tube is too
> long does us little good unless we have an idea of what you think the right
> length is. Sure, you guys know what numbers you mean, but if you're trying
> to educate us then you've got to let us in on them too. Are we talking a
> couple of centimeters or a couple of inches. If its the former then I'll be
> on my way, but if its the latter then I'd like to hear more on the subject.
what i'm talking about is nothing that makes the c'dale a bike you're
unable to fit yourself on.
qrman
Dan Empfield
<intern...@cervelo.com> wrote:
> Anyway, I would be interested in knowing what measurement people prefer,
> headtube length or top tube height, as I would gladly convert the tables
on our
> website to reflect that preference.
maybe we should consider, gerard, another measure, something we might call
headtube drop (or some similar wording). it would be the difference
between lines parallel to the ground from the seattube top to headtube
top.
i think that would cover it. it doesn't matter where your BB is, your
butt is where your butt is vs the headtube top. if you drop the BB, you
shorten the headtube to compensate, right?
this assumes that everybody's seattube top stops at a place common in the
industry (i.e., people 6' tall ride 58cm or 59cm bikes, people 5'5" ride
48 or 49cm bikes). that is really the only reason we extend our
seattubes. otherwise we'd cut them off low, like MTB bikes. it's just
too confusing to explain that to people, though.
>If Cannondale dealers are going to set-up their customers correctly
> this year, the sales of Look Ergostems should be booming. Look is therefore
> rated a strong buy :-).
god i hope so. i've got a bucketload of these i'd like to unload cheap.
qrman
cog...@grecc1.ab.umd.edu
> i now see the fundamental difference in our views, that you feel an aero
> downtube is more efficacious than an aero seattube (even cervelo's
> precisely and admirably done one).
Very well said. However, I'm not 100% sure I want to be painted into that
corner - the fact is, I have never seen any data for a bike w/ an aero
seattube and a round downtube. So, at the risk of sounding like I'm waffling,
let me say that my guess is that both features (done properly) are roughly
equally efficacious.
> 1. the seattube, and things backward from it, are the last thing the wind
> sees; the downtube is in the middle of the bike; i suspect that doing what
> you can to reconnect the wind is the more important mission.
Well, on every bike I've ever seen there's an awful lot that's behind the
seattube, including the rear wheel, rear derailleur (on a road bike), rear
brake, chainstays (on some bikes), seatstays (on some bikes), and perhaps
most importantly, the rider's moving feet and lower legs (during at least
part of the pedal stroke). Intuitively, I would therefore suspect that the
benefit to an aero seattube has more to do with how it affects the airflow in
its immediate vicinity, rather further back on the bike. But, this may simply
be a matter of semantics...
> 2. the other problem that occurs behind the seattube is the turbulence of
> the rear wheel; an "aero" seattube has the triple mission of being aero
> itself, reconnecting the wind behind the bike & rider, and fairing the
> rear wheel; the downtube just sits there and looks pretty;
And, as you always like to point out, the downtube is also important in
stiffening the b.b. But, let's say that you can live w/o that stiffness, or
have a way to work around it (i.e., stiffen other frame members) - an aero
bike w/o a downtube is a Chet Kyle-designed Dupont prototyle, or Jim Glover's
steel Z-frame, or a Lotus. An aero bike w/o a seat tube is a beam bike (Zipp,
Softride), or a Kestrel 500SCi (which still has seat stays). Are these bikes
really different in drag? W/ the exception of the Kestrel, no - in fact,
there is really very little difference in drag between such exotic designs
and more traditional looking bikes like the Hooker, GT SB-1, or the Cervelo
P2 (although all are much lower in drag than a traditional round-tubed bike,
at least w/o a rider). This shouldn't be the case if the seattube is all
important and the downtube just has to sit there and "look pretty".
One of my teammates, a very bright fellow (who happens at one point to have
worked for Hooker), once used the phrase "moving material around", which I
think is a very apt description. That is, it requires a certain amount of
metal or carbon fiber (or bamboo) to connect the wheels, cranks, saddle, and
handlebars, and still provide adequate strength/stiffness, and given these
constraints it doesn't seem to matter all that much where you place the
material, as long you make sure that whatever structure you do include is
designed with attention to its aerodynamic properties. Yes, there may be a
slight advantage to getting rid of tubes, or to combining the rear wheel and
seattube into one aerodynamic object, but the biggest step forward comes from
simply using aerodynamic tubing instead of roung tubing in a double-diamond
design...
> 6. it has also already been established by the tester you and i are most
> familiar with that one particular bike, very "hot" in the previous two or
> three years, sporting simply an aero downtube and no other aero tube,
> tested pretty much identically to round tubed bikes; the argument i've
> heard in response is that this tube was not the "right" aero tube, but
> really, the shape wasn't bad at all; the aero tube here just didn't work.
Hmmm - the data I've seen indicate that using an aero downtube of the right
shape DOES work - in fact, it seems to work better than putting a fairing
behind the head tube, and about as well as using an aero seattube w/ a
cut-out (I say "about", because I've never seen any direct comparisons of the
two approaches. However, according to the Cervelo website the P2 has (IIRC)
~0.3 lbs less drag than the Eyre, and also that the rear wheel cut-out "makes
the rear wheel disappear". A difference of this magnitude would mean that the
P2 has about the same drag as I have measured for my Hooker, which is what
one might expect given their similarities.)
> you're not swayed by, or in agreement with, the above reasoning, and i
> accept that.
Au contraire! I'm now more convinced than ever that I need to replace my
Hooker w/ a P2, since it has that nice rear wheel cut-out and my bike
doesn't. ;-)
Dan Empfield
<shi...@vctinc.com> wrote:
> What I'm trying to discover is just what sort of seat to bar drop you feel
> is adequate. That seems to be the number that you guys are focusing on.
> That number is not availabe from the dimensions on your web site because you
> measure the seat tube c-t rather than c-c. Even if you measured c-c, I can'
> t tell if your top tube is sloped or horizontal, which would also need to be
> taken into consideration.
i know what you mean, but just so others don't get confused, it doesn't
matter where the center is (the junction of the seattube and top tube) and
it doesn't matter if the top tube is level, drops, or rises. the merlin
aerial has a sloping top tube, has a very different c:c measure than QR,
and yet is almost exactly the same geometry as the QR (merlin has a fixed
style of seattube butt length at the top, you can't weld down the seattube
past the butt, so you have to weld up toward the top of the seattube and
slope the tube down to the headtube). the ONLY thing that matters is
where the headtube top is vs the saddle. any way you want to get there as
a builder is okay.
> Good grief, here we go 'round in circles... I think I'm getting dizzy. Too
> long by how much? What should a typical triathlete look for in a seat to
> bar vertical distance?
explained quite precisely on our website, which is what this means to us,
not necessarily to gerard.
> If it varies with frame size then can we make it a
> percentage of the top tube length? I really would like to understand what
> your idea of proper fit is but this nebulous "too long" really gets me
> nowhere.
i can't speak for gerard, but we have a precise formula (well, it's
precise, but it yields a range), on our website to get specifically to
what you are asking above when you describe "seat to bar vertical
distance". it is what we call "armrest drop". as to what the headtube
lengths need to be to get the armrest drop you're looking for, simple.
ours. or gerard's. if we thought it should be a different length, we'd
make our bikes with a different length. you know now where to get our
geometry on our websites, you can check for yourself what c'dale's
headtube length is vs what ours is. but maybe we ought to talk about
headtube drop (vs seattube top), this would yield a measure that is
irrespective to whether the bike is 700c or 650c.
but even then, what if i hacked my seattubes off just above the top tube
junction? then my 57cm bike would really be a 50cm, measured c:c, and
52cm c:t. then you've got to talk about cockpit, and measure the headtube
top against the cockpit. but then you're back to getting a different
measure for 650c and 700c.
perfectly clear, eh stacy? it's not an easy problem to solve using only
the traditional measures of bike fit, geometry, and sizing. but then,
triathlon is young. younger yet are aero bars. younger yet are bikes
designed for aero bars. younger yet are newer style aero bars that put
the armrest in a specific position in relation to the stem clamp, causing
us bike makers to conform our geometry to specific types of bars (well,
really syntace). younger yet is the awareness on behalf of the customer
base that all this is important. so you've got measures that do not
describe with any sense of commonality or industry standard the features
we are talking about.
the REAL problem is that the important measure is headtube top to saddle
top. frames don't have saddles. so how do you describe, as a frame
maker, how your frame solves the problem? fortunately, we still use
seattube lengths that correspond to rational and understood ideas of
sizing, as i described above. so you could make a chart and say that tri
bikes made 60cm c:t, with saddle top to BB axle length of around 80cm
being what is the assumed saddle height on such a bike, should have a top
to bottom head tube height of, say 16cm (or whatever).
> I've snipped the rest of your post because my above statement was rude and
> uncalled for. I'm sorry. I hope that you and Dan will accept my apology
> and not ditch this thread for a little while longer. I'm not through
> picking your brains.
no way man!! i was glad to see your comment! it's boring as hell w/o a
little spice here & there!
qrman
Rick Denney
>We have chosen to list headtube length, as it is a lot easier for people to
>measure and compare. It can be done on a frame, whereas for the top tube height
>the customer can only measure it when the bike is built up.
The only problem with this is that the length of the head tube is not
important without knowing the BB height. You are interested in the
relative height of the top of the head tube versus the BB--that's what
tells you how aggressive your position can be.
The Habanero has a rather tall BB. Though I don't have my drawing with
me (I'm in Denver this week), I remember it being a good couple of
centimeters higher than my Trek. That's how it works around the bigger
wheels. And while I generally agree with Dan that a shorter BB height
is desireable, I can't say that the Habanero takes any hurt from being
taller. The bike is extremely stable.
The only way to compare these things in a shop is by standing up a
bike (very straight) and measuring along a plumb line from a level
floor. Measuring from point to point on the bike requires to much trig
for mortals, heh, heh.
Rick "Wishing I had all the bikes in my basement to measure them up"
Denney
Rick Denney
>
>What I'm trying to discover is just what sort of seat to bar drop you feel
>is adequate. That seems to be the number that you guys are focusing on.
>That number is not availabe from the dimensions on your web site because you
>measure the seat tube c-t rather than c-c. Even if you measured c-c, I can'
>t tell if your top tube is sloped or horizontal, which would also need to be
>taken into consideration.
>
This is why I measure from the floor. I want to know how high the BB
is, how high the top of the head tube, and how high the saddle, with
the proper distance from the BB to the saddle for me. And I want to
know how far the center of the saddle (I have a particular spot in
mind) is from the BB, measured horizontally, and I want to know the
distance from that spot on the saddle to the handlebar. Those
dimensions tell me about body position. Notice that the lengths of the
tubes don't appear on my list.
The difficulty is in providing dimensions of a bare frame, which is an
abstraction from the dimensions that really count.
Weight balance and handling required another set of dimensions.
Rick "Stay Tuned" Denney
Seth Moore
bike. He loves it except for the following points.
1. Paint is already falling off by the handfuls.
2. Space between rear wheel and seat tube is critical and set up for
clinchers only. He had to dig up a special spacer system to use a tubular
disc wheel which was a pain.
3. He does Ironman triathlons (6th at the Great Floridian) and will
qualify easily for Kona this year. Only problem is that the bike is killing
him after 50 miles. Extremely stiff and beating him to death. He now wants a
Softride and I have to be careful riding with him as I sometimes catch him
lustfully eyeballing my Zipp especially around the 3 hour mark.
With all that said, about the only thing I would consider trading my Zipp
for is a P2 or maybe a Lotus for the little 10 mile and 40K TT's that I try
to do. The P2 workmanship is unreal except for the paint.
Seth
cog...@grecc1.ab.umd.edu wrote in message
<7d62b8$12e$1...@nnrp1.dejanews.com>...
Ken Lehner
> Andy - I talked a friend of mine into a Cervelo P2 last year. Beautiful
> bike. He loves it except for the following points.
>
> 2. Space between rear wheel and seat tube is critical and set up for
> clinchers only. He had to dig up a special spacer system to use a tubular
> disc wheel which was a pain.
Where is this spacer, and how does it affect tire/seat tube clearance? I
can't picture this space.
> 3. He does Ironman triathlons (6th at the Great Floridian) and will
> qualify easily for Kona this year. Only problem is that the bike is killing
> him after 50 miles. Extremely stiff and beating him to death.
I was under the impression that the vertical compliance of all double-diamond
(non-suspended like a Zipp) bicycle frames was, for all intents and purposes,
identical. If indeed he is suffering after extended time in the saddle, it
ain't the frame.
I'd suspect his position as set up on that bike is not optimal.
Ken "I'm not Rick Denney" Lehner
Dan Empfield
> Hmmm - the data I've seen indicate that using an aero downtube of the right
> shape DOES work - in fact, it seems to work better than putting a fairing
> behind the head tube
i haven't seen this. point me please. i think you're specifically taking
a dig at our bike here, so i'd really like to know where these numbers
that you've SEEN are coming from. i might also point out that the bikes
you quote just above in your post, lotus, zipp, softride (i take it you
mean the monocoque) having a trailing edge to the head tube. i wonder how
you are able to both split out the benefit of this feature, vs not having
such a feature, and the benefit of the aero tube by itself, absent this
feature?
please don't quote me drag numbers off cervelo's website which have not
met the criteria you've set for all other companies for the validity of
such numbers. i'm fairly uninterested in the plethora of such numbers put
out by bike & wetsuit companies, all showing that their in-house or
company-sponsored tests prove that their bike or wetsuit is the world's
fastest.
qrman
Dan Empfield
<shi...@vctinc.com> wrote:
> I quite like the point about the 90 degree stem and the spacers. Thanks for
> pointing that out.
i take it you saw my post re this, that they are not 90 degree, they are +
or - 6 degree, i.e., they are 84 degree or 96 degree, and because they are
two-piece stems you can flip them over and back.
re the spacers: are you really advocating that there be no stack and
therefore no possibility for stem height adjustment?
something to remember about this type of system, the only way you can get
all the adjustability available is to have some stack, as you might want a
position that requires the "minus six" degrees with 15mm of stack, which
would be slightly lower than, say, no stack and "plus six degrees".
qrman
cog...@grecc1.ab.umd.edu
> I wrote:
>
> > Hmmm - the data I've seen indicate that using an aero downtube of the right
> > shape DOES work - in fact, it seems to work better than putting a fairing
> > behind the head tube
>
> i haven't seen this. point me please. i think you're specifically taking
> a dig at our bike here, so i'd really like to know where these numbers
> that you've SEEN are coming from.
Ah, so now the shoe is on the other foot! Now do you see why I always try to
encourage people to publish their data? But, to answer your question, if I can
get permission to do so, I will share the numbers.
> i might also point out that the bikes
> you quote just above in your post, lotus, zipp, softride (i take it you
> mean the monocoque) having a trailing edge to the head tube. i wonder how
> you are able to both split out the benefit of this feature, vs not having
> such a feature, and the benefit of the aero tube by itself, absent this
> feature?
I'm sorry, I don't exactly understand what you mean here - perhaps if I look
at my own unsnipped post I can figure it out.
> please don't quote me drag numbers off cervelo's website which have not
> met the criteria you've set for all other companies for the validity of
> such numbers.
Correct me if I'm wrong, but when have you EVER posted even a SINGLE piece of
data for e.g., drag of a QR bicycle? I know you haven't - if you had, you can
be assured that it would be entered into my mental database, along with any
information needed to put it into its proper perspective (e.g., who did the
testing, how did they do it, do I have reasons to trust or distrust that
person, etc.). So, given that you haven't shown any willingness to share such
data w/ the world of r.s.t., much less attempt to publish it in a
peer-reviewed journal (as you once claimed you were working your way up to),
I don't have much sympathy for your claim that I'm setting too high a
standard for you. Indeed, given that you have led me to believe that you
don't even have much in the way of original data (instead getting most of
your information second-hand, just like me), it would seem to be a moot point
anyway...
Dan Empfield
[snip]
i'm not going to get into it with you. do what you want. say what you want.
qrman
Cervelo Cycles
Stacy Hills wrote:
> SNIP Sure, you guys know what numbers you mean, but if you're trying
> to educate us then you've got to let us in on them too. Are we talking a
> couple of centimeters or a couple of inches. If its the former then I'll be
> on my way, but if its the latter then I'd like to hear more on the subject.
>
> Do tell.
I thought those numbers were mentioned, but here they are. A 56cm C'dale
Multisport has a headtube 5cm longer than a 56cm Cervelo (Eyre Tri and P2 have
the same geometry). The difference in top tube height is the same, as is the
difference in saddle to bar vertical drop for the same saddle height (if the bb
heights of the frames are similar, all these measurements are more or less
telling the same story). To me that is a lot for the following reason: when we
set people up on our tribikes, we seldom use more than 3cm of spacers, let alon
5cm. So Those people would have a hard time getting in the same position on the
C'dale, as that would require a negative height in spacers. the only option to
get into the same position would be the use of a special stem (such as a Look
ergostem), but that obviously isn't very useful in the long run. We use an 82
degree stem, which is flippable to 98 so there is some extra height that people
can gain if they really want to without needing too many spacers. The C'dale
comes with a 90 degree stem, which brings the bars even higher than our 82
degree stem would. this is not a big issue as you can easily get another stem,
but you won't find much better than a 73 degree stem for the C'dale. All in all,
the difference in minimal bar height between the Cervelo and the C'dale with
both using their standard stems is 55mm, with the flattest possible stem on the
C'dale and the standard stem on the Cervelo it would be 45mm. I hope that gives
a good impression on the difference between the two bikes. It is pretty similar
for the other sizes if I read the charts, but I can't give exact measurements as
I only have measurements of a 56cm C'dale.
If you have any further questions, please do not hesitate to contact me.
Sincerely,
Cervelo Cycles
Stacy Hills wrote:
> Well, that's assuming a horizontal top tube. The reason I requested this
> number is that Gerard made a statement about Cannondale's top tube not
> really being sloped.
I am not sure if I did, if I did it was a typo. The top tube isn't really
sloped, but that is not that important to me. What I think I said, and what I
wanted to say is that the top tube is not really dropped that far (they say 3cm
in the geometry chart, but I am not sure how they measure that.)
> I didn't know whether this was to imply that his top
> tubes do slope so I figured I'd take it as yes they do.
No they don't as I don't see the point to that. This is where it gets all
confusing and this is also the reason why headtube length is such an easy
dimension to use. No matter if the top tube is horizontal or sloped, what really
determines how low your bars can go is the headtube length. And how do you
measure top tube height on a sloped tube.
Cervelo Cycles
Mark Hickey wrote:
> The only thing that will impact the "drop" from the saddle to the bars
> is the difference in height of the top of the top tube and the top of
> the seat tube. QR has chosen to increase the seat tube length above
> the top tube to achieve this. I've also subscribed to this approach,
> and my frames have approx 1" (2.5cm for you Yurrupeans) of reinforced
> seatpost extention above the top of the seat tube. That's obviously
> less than the QR, which appears to have maybe twice that much (don't
> see a spec for that either).
>
> But if you have two bikes with horizontal top tubes, and that are
> measured the same way (i.e. c-c or c-t), the length of the head tube
> becomes a virtual non-issue.
> You have to have a certain amount of HT
> extention above the top tube, and that's not gonna vary by more than a
> few mm's between manufacturers.
Wait a second. If C'dale drops the top tube 1 inch and I drop it three, than my
headtube is 2 inches shorter if we both use horizontal toptubes and our bb is at
the same height. Yes both our toptubes stick out equally far above the top tube,
but my top tube is lower so my headtube is shorter. Of course c-c my seattube
measures different from C'dale's.
Now say you are a customer and you are sized correctly. So the shop tells you
that the top tube length is the first thing to look at, and you need a 54cm top
tube. That means that you need the C'dale that they call a 54cm frame, a QR that
they call a 57cm or a Cervelo that we call a 54cm. Now how we call that frame
(54, 57 or 137) is not important, what is important is that you get a bike with a
54cm toptube. When you look at the headtube lengths of these three frame, the
C'dale is the longest. You could get a shorter headtube by getting the C'dale
that has the same c-c seattube length as the QR or the Cervelo, but that bike
would have a top tube that is way to short for you. So I don't understand how you
can say headtube length is a non-issue. It would be if it were the only variable,
but if you pick your frame by headtube length, you will be stuck with a certain
top tube length. And my contention is that sometimes QR's toptube length may fit
you best, sometimes Cervelo's, but I see very few people for whome C'dale's
toptube length would be correct.
I hope this is somewhat clear, but it's a difficult subject to explain in
writing.
> Looking for the answer in the total height of the top of the head tube
> is pointless as well, since it's all relative to the the height of the
> bottom bracket (or inversely relative to the bottom bracket drop, but
> that sounds too complicated).
>
This is true, but the variation in bb heights is relatively small to the
variation in top tube heights, so the headtube length will give a rough
indication.
Cervelo Cycles
> In article <36F597...@erols.com>, andya...@erols.com wrote:
>
> > From the b.b. forward, the only difference (AFAIK) between the P2 and the
> > Eyre is that the former has internal cables whereas the latter has
> > exposed, bare cables.
Not exactly true. Both the P2 and the Eyre Tri have internal cable, only the
Eyre Road and the Renaissance have external cables.
Gerard.
Cervelo Cycles
Dan Empfield wrote:
> 1. the seattube, and things backward from it, are the last thing the wind
> sees; the downtube is in the middle of the bike; i suspect that doing what
> you can to reconnect the wind is the more important mission.
>
I don't quite understand this. It's like saying that a convertible will have
the same fuel economy as the coupe it was derived from, because the front and
rear are the same and the middle part doesn't matter. This obviously is not
the case.
Furthermore, I think we both agree that a good aero fork and an aero front
wheel are important. What do these two items do if they are aero? Being aero
means they don't disturb the airflow much. so behind them, the airflow is
still pretty nice. And now all of a sudden it is not important anymore if it
hits something aero or non-aero? Why? If it is important that the undisturbed
flow hits an aero fork and an aero front wheel, then it is also important that
the almost undisturbed flow that comes of the wheel and fork hits an aero
downtube.
> 2. the other problem that occurs behind the seattube is the turbulence of
> the rear wheel; an "aero" seattube has the triple mission of being aero
> itself, reconnecting the wind behind the bike & rider, and fairing the
> rear wheel; the downtube just sits there and looks pretty;
>
No doubt that the seattube has some important tasks that the downtube doesn't
have.
> 3. the seattube is much more perpendicular to the wind than the downtube,
> which is already pointing in a line more parallel to the wind than
> perpendicular.
>
Also true, but it doesn't necessarily mean that the downtube is of no
importance. It just means that on a round tube bike, the downtube isn't quite
as bad as the seattube, although the round seattube also has it's advantages
if it is close to the rear wheel. For example, we have found that a seattube
with a cut-out for the rear wheel performs worse than a round tube if the gap
between tube and wheel is too large (more than a 1/2"). That is why the P2 has
horizontal drop-outs, so that no matter what tire you use, you can always run
it close to the tube. We suggest 2-3mm.
> 4. the downtube usually carries the water bottle behind it, mitigating any
> positive effect the aero aspect of the tube will have; the P2 has no water
> bottle bosses here, which basically is gerard's statement that a water
> bottle here is going to severely mess up what he's trying to achieve
> aerodynamically (else why is such obvious needful items as water bottle
> bosses removed?); the eyre, i believe, has the bosses (correct me if i'm
> wrong), which is gerard's way of implicitly stating that the buyer of the
> bike is less sophisticated, and so will probably not resort to ingenious
> and convoluted ways to get his water placed elsewhere on the bike; thus
> resulting in the aero catastrophe gerard so wants to avoid on the P2.
>
sorry for all the trouble you went through to explain my implicit statements,
but the Eyre Tri does not have water bottle bosses on the downtube, for the
same reason they are not to be found on the P2. Here is my explicit statement:
Don't use water bottles anywhere on the frame. not on the downtube, not on the
seattube. Put them behind the seat and/or use a Jetstream or similar system.
We do have water bottle bosses on the seattube, for those who go on long
training rides with no aid stations. But I would never suggest to use them in
a race.
> 5. it has already been established that bikes that really are somewhat
> more aero, however slightly, from standard frames, often-- or usually--
> are so because of faired seattubes and either faired or missing
> seatstays: the carbon monocoque softride (which has a decidedly unaero
> downtube, yet still is reasonably aero, albeit the word i hear is that it
> is mortal without a rear disc, but is very aero with one); lotus; hotta.
> all these bikes use the seattube to fair the rear wheel, with only one set
> of stays instead of two, except the softride, which doesn't fair the rear
> wheel (hence the hubbub that the rear should be a disc), but this bike has
> no seattube or stays to mess up the wind back there.
>
I am not sure I understand this whole point, but it is true that a Softride
really needs a disc to get reasonable aero performance.
> 6. it has also already been established by the tester you and i are most
> familiar with that one particular bike, very "hot" in the previous two or
> three years, sporting simply an aero downtube and no other aero tube,
> tested pretty much identically to round tubed bikes; the argument i've
> heard in response is that this tube was not the "right" aero tube, but
> really, the shape wasn't bad at all; the aero tube here just didn't work.
>
I am not sure about which bike and tester you are talking, so it's hard to
comment on that.
> the very easiest thing to do is put an aero downtube in a bike. the
> really hard thing to do is put an aero seattube in it, with corresponding
> aero seatpost, and a nicely faired downtube that is sucked up pretty far
> inside the seattube. that's really hard to do.
What do you mean here? The downtube inside the seattube? do you mean combining
the two into one tube, making it a Lotus style bike?
> but i think that's what
> is likely to help the most, for reasons stated above. i think the eyre is
> a fine, very rideable bike, but i think-- as everybody knows now thru my
> droning on ad infinitum-- that if you are going to mess with the downtube
> you'll pay,
Well, even if you don't buy in to the aerodynamics of the Eyre Tri, the bike
is of very similar weight to any other tri bike out there, and it is stiffer
in the bottom bracket than any Easton bike I have ever tested.
Now if we were to make a bike with a round downtube with the same technology
(e.g. the differential butting), the bike would be even stiffer. But as it is
already stiffer than most other bikes, I don't really see the point in that.
Instead, I prefer to have the aero advantage, and the fact that you don't
believe in it doesn't slow me down.
Sincerely,
Cervelo Cycles
Stacy Hills wrote:
> What I'm trying to discover is just what sort of seat to bar drop you feel
> is adequate. That seems to be the number that you guys are focusing on.
> That number is not availabe from the dimensions on your web site because you
> measure the seat tube c-t rather than c-c.
OK, I wasn't being clear here. We do measure c-t, but we don't have a seattube
extension past the top tube. So our c-t measurement is really close to a
center-top of top tube measurement. When you compare these dimensions with the
C'dale you will find that it is not quite 5cm, which I stated before. This is
partly due to the fact that we measure slightly different as explained above,
but also because in most of the little details, I think we have made more
informed decissions than C'dale has.
for example, we wanted short headtubes with the downtube and toptube as far
apart as possible (it increases torsional stiffness, and we don't want too much
verlap between the aero downtube and the toptube), So both tubes are positioned
extremely close to the ends of the headtube, probably at least 5mm and maybe
10mm closer than the C'dale. So for both sides combined that makes an extra
10-20mm that we gain on the C'dale and that is not reflected in the c-t
measurement.
Furthermore, our bb is 5mm higher than the C'dale, so again we gain some drop on
the C'dale. It all adds up, so all the little thinks combine for 5cm in the end.
By the way, the reason we don't use a seattube extension is that it serves no
purpose that I am aware of. It enables people to measure the frame size by
measuring the length of the seattube, but they can easily find that out some
otehr way (measure another tube, or having a sticker on the frame, or putting it
in the serial number). We don't use the extension because it makes some people
forget that they have to put their seatpost past the seattube-toptube joint.
Some think that if the seatpost is in past the MAX line, it's OK. but the truth
is that it may still not be past the weld, and this catilevered seatpost puts a
lot of stress on that joint. I have seen frames fail at that spot because of
that reason. So we cut the seattube just above the headtube. It means that the
seatpost is always inserted past the joint, and no additional stresses are put
on the joint. And the drawback of having to measure framesize some otehr way is
negligible. Oh, and cutting the seattube shorter saves 18 grams :-)
> Even if you measured c-c, I can'
> t tell if your top tube is sloped or horizontal, which would also need to be
> taken into consideration.
>
It is horizontal.
> Good grief, here we go 'round in circles... I think I'm getting dizzy. Too
> long by how much?
Our posts are crossing, mostly because I seem to get them two days late in some
instances. Anyway, I think that on a 56cm frame, they are 5cm too long. That is
the short answer, the long and more sophisticated one can be found in another
post I just did.
Mark Hickey
>In article <36f5541f...@news.nuri.net>, mhi...@cynetfl.com wrote:
>
>> On the whole "length of the head tube thing".... It's kinda hard for
>> me to make a real comparison with QR's geometry, since there doesn't
>> appear to be any reference on their website as to whether the bikes
>> are measured center to top or center to center.
>
>center to top. center to center would be kind of hard, since the center
>is up to 10cm below the top with a dropped downtube.
I see from a later post that you measure your frame center to
top-of-the-seat-tube-binder. That's counter to almost all other road
bikes, though not uncommon among MTBs. It does, however make it
impossible to compare the "same size" frame. It appears that you'd
subtract about 5cm to get a "traditional" center-to-top (of top tube)
measurement.
>> The only thing that will impact the "drop" from the saddle to the bars
>> is the difference in height of the top of the top tube and the top of
>> the seat tube. QR has chosen to increase the seat tube length above
>> the top tube to achieve this. I've also subscribed to this approach,
>> and my frames have approx 1" (2.5cm for you Yurrupeans) of reinforced
>> seatpost extention above the top of the seat tube. That's obviously
>> less than the QR, which appears to have maybe twice that much (don't
>> see a spec for that either).
>
>what would knowing that measurement do for you, mark? if there is some
>good reason to have it i'll be glad to publish it. these measurements are
>no secret we're trying to keep. we don't measure the distance from the
>midpoint of the headtube to the rear brake bridge either, but i'm happy to
>include it if anyone wants it.
I wasn't really all that curious, just trying to explain the
difference in sizing between the QR and some other frames.
>> But if you have two bikes with horizontal top tubes, and that are
>> measured the same way (i.e. c-c or c-t), the length of the head tube
>> becomes a virtual non-issue.
>
>THE important issue is where is the headtube top in relation to where the
>saddle is going to be. the headtube bottom is fixed, you can't change
>that. so where the top is, that is a function of the headtube length, and
>in that sense the headtube length is really important.
But not by itself.
> but i will grant
>you this, the headtube length is just an extrapolated measure you can pick
>on. what really matters is where is the headtube top in relation to the
>saddle, per fixed frame size.
Yes, what matters is saddle-to-headtube top.
>> But, I have to wonder... if getting the bars low is the holy grail of
>> setting up tri-bikes, why oh why do all the bikes on the QR website
>> come equipped with 90 degree stems?
>
>they don't. they come with + or - 6 degrees and 25mm of stack, so that
>you can have an extremely adjustable bike (the website only shows bikes
>with + or - 6 degrees, you must be looking at someone else's site).
Naaahhh. I guess I just couldn't make out the difference on my
browser. But I did guess right on the stack at least....
>plenty of our customers start 5cm, 6cm, 7cm higher when the first get a
>QR, and get lower gradually, as they become more accustomed to this style
>of riding, are able to accommodate a lower position, and are set up and
>re- set up by their LBS. we do show our site as having the stems in the
>+6 degrees position, but for some of our pros even the -6 with no stack is
>not low enough. riccitello has a -15 degree stem w/no stack on his PR.
Adjustability is good. That's why I still prefer threaded stems.
Call me a retro-grouch, but I like being able to tweak my stem up and
down without pulling the bike apart and moving washers. Besides,
they're not very aero.... ;-)
>> Looking for the answer in the total height of the top of the head tube
>> is pointless as well, since it's all relative to the the height of the
>> bottom bracket (or inversely relative to the bottom bracket drop, but
>> that sounds too complicated).
>
>okay, i'll bite. all bike makers agree that the lower you can make the BB
>the better, for handling.
Until you put your pedal down in a corner, which is very bad for
handling. I like to pedal through corners.
>the headtube bottom is fixed, and is higher for
>your 700c bikes than for anybody's 650c.
Yep.
> your BB is lower (BB drop
>greater), surely, than 650c bikes, probably on average 6cm to 7cm of BB
>drop to our average of 3.5cm to 4cm.
But BB drop can't be directly compared between 650 and 700c bikes. BB
height can. I suspect it's pretty close, but I'd guess my BB's are a
little higher than QR's.
> so your saddle is lower to the
>ground, and your headtube bottom is higher from the ground than a 650c
>bike, to start with.
Why is my saddle lower? If the BB is in the same place, the saddle
will be exactly the same height. My headtube bottom IS higher, but
that doesn't change anything else.
> that means that you'd need a considerably smaller
>headtube just to get where you need to get to be the same as any 650c
>bike. that's hard to do with 700c.
But the headtube length is chosen as a function of where the top needs
to be, not just where the bottom starts. It's just not a useful
measurement in itself, without knowing all the other parameters.
You see, the difference as I see it is moot because I assume that a
rider will fit on either a 650 or 700 bike that....
1) has the same BB height and
2) has the same "seat tube height" (measured the same way)
That is, start at the same BB height, measure up a 78 degree seat tube
to the same "height", extend a horizontal top tube, and it's gonna
impact the head tube at the same exact place and height, whether that
head tube houses a 650c fork (in which case the BOTTOM of the HT will
start lower) or a 700c fork. End result is exactly the same, relative
to the top of the head tube, which is all that matters. Another way
to look at it is that a Habanero frame 2.5cm shorter than a QR frame
(if they're measured c-t of the top tube) with a 2.5cm longer seat
post extention will be pretty close to identical to a QR in fit,
assuming they had the same top tube length.
>hey, maybe that's why time trial bikes have had a 650c front for the past
>generation!
And 24" and 700.... The pros need a radical position to set records,
that none of us mere mortals should worry much about. Look at the TT
bikes the Yurrupean pros use on the road courses, and most of 'em have
two 700's - but either works great (let's not get that particular
thread started up again).
Mark Hickey
Habanero Cycles
Website and email down due to ISP problems
561-684-8444
Mark Hickey
>Mark Hickey wrote:
>
>> You have to have a certain amount of HT
>> extention above the top tube, and that's not gonna vary by more than a
>> few mm's between manufacturers.
>
> Wait a second. If C'dale drops the top tube 1 inch and I drop it three, than my
>headtube is 2 inches shorter if we both use horizontal toptubes and our bb is at
>the same height. Yes both our toptubes stick out equally far above the top tube,
>but my top tube is lower so my headtube is shorter. Of course c-c my seattube
>measures different from C'dale's.
If you want to measure based on saddle height, you have to add in the
seatpost. SO... If you're on a 4" shorter Habanero with a 4" longer
seatpost, my head tube is shorter than the Cervelo. There has to be a
realistic way to compare frame of the same "size"... To me, that's
center to top of the top tube. That produces a constant way of
determining standover height (when added to BB height, of course).
This is the critical parameter as to top tube height, and standover
height.
>Now say you are a customer and you are sized correctly. So the shop tells you
>that the top tube length is the first thing to look at, and you need a 54cm top
>tube. That means that you need the C'dale that they call a 54cm frame, a QR that
>they call a 57cm or a Cervelo that we call a 54cm. Now how we call that frame
>(54, 57 or 137) is not important, what is important is that you get a bike with a
>54cm toptube.
Ahhhh, but which of them can the rider stand over? What matters there
is the height of the top of the top tube. Top tube length is
important too, of course, but if the Cervelo 54cm frame has a SO
height of 1cm higher than the crotch height of the rider, the top tube
length doesn't matter.
>When you look at the headtube lengths of these three frame, the
>C'dale is the longest.
But how can you compare them? QR measures to the top of the seat tube
clamp, and the Cervelo frames have 700c wheels. These are not
comparable frames in any way other than the top tube length.
>You could get a shorter headtube by getting the C'dale
>that has the same c-c seattube length as the QR or the Cervelo, but that bike
>would have a top tube that is way to short for you. So I don't understand how you
>can say headtube length is a non-issue.
Because it doesn't mean anything by itself. You can't compare the
HT's directly between 650 and 700 frames. What matters is really the
TOP of the head tube (aka the height of the top tube).
> It would be if it were the only variable,
>but if you pick your frame by headtube length, you will be stuck with a certain
>top tube length.
That's a scary thought... ;-) That's why c-t is the "normal" way to
measure road frames - it nets the most meaningful fit numbers to the
potential rider. That is, on frames with approximately the same BB
height (not drop), frames with the same c-t seat tube height (and
angle) and the same top tube length are gonna fit the same. You might
factor in the final saddle position - and whether you can achieve it
with a "short post in a long seat tube extention" or a "long post in a
short seat tube exention" or a "longer post in an even shorter seat
tube extention" is immaterial.
>And my contention is that sometimes QR's toptube length may fit
>you best, sometimes Cervelo's, but I see very few people for whome C'dale's
>toptube length would be correct.
I know my own trusty C'dale (an '85) was pretty darn short too...
>I hope this is somewhat clear, but it's a difficult subject to explain in
>writing.
It sure is.... I'm really not taking exception to much that has been
said on the subject, but trying to find a realistic way to compare the
very different approaches to achieving much the same end result.
Going fast... ;-)
>> Looking for the answer in the total height of the top of the head tube
>> is pointless as well, since it's all relative to the the height of the
>> bottom bracket (or inversely relative to the bottom bracket drop, but
>> that sounds too complicated).
>>
>
>This is true, but the variation in bb heights is relatively small to the
>variation in top tube heights, so the headtube length will give a rough
>indication.
True, but only between bikes with similar size front wheels (and
tires, of course)
Mark Linenberg
wrote:
>In article <7d6gpj$eh7$1...@nnrp1.dejanews.com>, cog...@grecc1.ab.umd.edu wrote:
Don't let this thread stop now... this is just getting interesting.
I guess maybe it's time to get back to work.
As everyone diligently discusses the virtues of aero tubing,
non-aerotubing, etc, the March 1, 1999 Velonews magazine states that
World Record cycling hour holder, Chris Boardman, needs to produce
ONLY three more watts to propel his round tubed bike compared to his,
hour record lotus bike. His hour record speed is around 36 mph, so at
lesser speeds- from any elite cyclist doing a typical time trial to
joe triathlete, the watt difference would be close to neglible.
Remember Rominger broke the hour record on a standard round tubed
frameset. The article said that his helmet made more of a difference
to increase his speed than his bike. Also, wheel choice was much more
important as well.
As long as your frame allows you to place yourself in an optimal aero
position is the only thing that seems to be important.
Mark Linenberg
o
__o </\_
\< __/\
/\o_ (()) (()) /
^^^^^^^^^^
cog...@grecc1.ab.umd.edu
> As everyone diligently discusses the virtues of aero tubing,
> non-aerotubing, etc, the March 1, 1999 Velonews magazine states that
> World Record cycling hour holder, Chris Boardman, needs to produce
> ONLY three more watts to propel his round tubed bike compared to his,
> hour record lotus bike. His hour record speed is around 36 mph, so at
> lesser speeds- from any elite cyclist doing a typical time trial to
> joe triathlete, the watt difference would be close to neglible.
> Remember Rominger broke the hour record on a standard round tubed
> frameset. The article said that his helmet made more of a difference
> to increase his speed than his bike. Also, wheel choice was much more
> important as well.
In all likelihood, Velonews is basing their claims on the testing done by the
German magazine Tour, which did indeed report that there was little difference
in the power required to pedal a Lotus vs. other bikes (e.g., Cheetah, Stork,
GT) around a velodrome at ~45 km/h. As Gerard has pointed out
previously, however, Tour made some mistakes in their calculations which
tend to obscure the differences between bikes. Furthermore, Peter Keen has
presented data in Cycle Sport collected on Boardman himself showing a
signigicant advantage for the Corima bike that Boardman used in his first
record compared to a standard round-tubed track bike, and the Corima has been
referred to by people who have tested it as "a pig in the wind tunnel" - so,
which do you think is right, Velonew's second-hand extrapolation, or Peter
Keen's first hand data?
As for Rominger, he went farther on his second attempt at the hour, when he
switched to a bike made of quite functional aero tubing...
pso...@hidro1.ist.utl.pt
> Correct me if I'm wrong, but when have you EVER posted even a SINGLE piece of
> data for e.g., drag of a QR bicycle? I know you haven't - if you had, you can
> be assured that it would be entered into my mental database, along with any
> information needed to put it into its proper perspective (e.g., who did the
> testing, how did they do it, do I have reasons to trust or distrust that
> person, etc.). So, given that you haven't shown any willingness to share such
> data w/ the world of r.s.t., much less attempt to publish it in a
> peer-reviewed journal (as you once claimed you were working your way up to),
> I don't have much sympathy for your claim that I'm setting too high a
> standard for you. Indeed, given that you have led me to believe that you
> don't even have much in the way of original data (instead getting most of
> your information second-hand, just like me), it would seem to be a moot point
> anyway...
>
> Andrew Coggan
Every once in a while this talk about drag experimental data comes up, and
then Andrew Coggan starts with his well known peer-review rant ;-)
But if you posed the question of bicycle aerodynamics to any possible peer
that had never thought about this specific problem, but with a strong
aerodynamics background, he/she would not understand why all this fuss, and
when confronted with the idea of testing every solution in the wind tunnel,
he or she would ask "What for?"... I don't claim to be such an expert, but
it's simple to see if some things aerodinamicaly make sense or not...So let's
go part by part: Head tube - This one is simple. Shortening the head tube
will decrease frontal area, so effectively decreasing drag. And there's the
plus of allowing better positioning on the bike. So short head tubes make
sense. Head tube shape - Not so simple...any head tube starts like a circular
cylinder (I won't even mention the ridiculous Litespeed head tube). Assuming
that there's no disturbance before the head tube, and that the surface of the
tube is smooth, we'll have laminar flow on the tube, which will separate long
before the 90deg line. So if you put a fairing after the head tube, the
fairing will be on separated flow, effectivelly delaying reattachment, which
will increase drag. And this is assuming that we're working with a yawn angle
of 0deg, because at an angle the existence of a fairing will increase the
extent of the separated area, thus increasing drag even more. Downtube - At
0 degrees, the downtube works on the wake of the front wheel, and I'm sure
that there isn't much difference between the drag of a round cylinder and an
airfoil shaped tube. But at increasing yawn angles, the influence of the wake
of the front wheel decreases, and the downtube works on undisturbed flow. So
it makes sense to use an airfoil shaped downtube, which will have less drag.
The problem with this is that for higher angles, the airfoil will stall, and
will have a higher drag than a circular cylinder. For exemple, for the NACA
0015 airfoil shape used on the P2, stall will happen for 16-18 deg. So the
circular cylinder shape is a good choice for every yawn angle, while using
the airfoil shaped downtube is a good choice for small yawn angles. Ellipsoid
shaped downtubes, like on the C'dale, behave like circular cylinder at 0 deg,
and worse than circular cylinders at increasing angles, because of the
increased frontal area. So these tubes only look more aerodynamic. Seat tube
- the seat tube works in a region influenced by the legs of the rider, so
it's difficult to make an analisys like the ones I did above. For 0 deg, and
for a rider with a "up-down" style, the legs won't influence the seat tube,
and it makes sense to have a seat tube that will function as the back wheel's
leading edge. Also reducing the gap between the wheel and the seat tube will
help this "wing" to work better. For increasing angles, the "outside" leg
will influence the flow on the seat tube, and probably the seat tube will be
working on a region of separated flow of the leg.
Now does this need experimental validation? Absolutely...But let's stop to
think before making ridiculous allegations, or before doing a bunch of silly
tests.
Paulo
Dan Empfield
> I see from a later post that you measure your frame center to
> top-of-the-seat-tube-binder. That's counter to almost all other road
> bikes,
now mark, think about what you're picking at here. the "center" on a
dropped top tube bike is anywhere from 3cm to 10cm lower than the seattube
top. so how can we possibly be able to measure the way other bike
companies do? in any case, you can compare what we do to other bike
companies c:c, because when we started dropping our top tubes we had to
figure out a way to make apples to apples comparisons. so we picked
cockpit lengths that corresponded with how a 57cm c:c (let us say)
"should" fit, and we just built our seattubes up to that spot, but
measured them c:t, since there is no "center" measurement that is in the
right place. i hope this isn't going to generate a response from you.
this is fairly straightforward i think.
> >THE important issue is where is the headtube top in relation to where the
> >saddle is going to be. the headtube bottom is fixed, you can't change
> >that. so where the top is, that is a function of the headtube length, and
> >in that sense the headtube length is really important.
>
> But not by itself.
okay, mark, you're right. the headtube is not the only important
dimension in the bike.
> Adjustability is good. That's why I still prefer threaded stems.
> Call me a retro-grouch, but I like being able to tweak my stem up and
> down without pulling the bike apart and moving washers. Besides,
> they're not very aero.... ;-)
i think threaded stems are fine. but they are not nearly as macro
adjustable as threadless, which is one reason we use threadless. they are
more micro adjustable, in that threadless are only adjustable in 5mm
increments, absent some really thin spacers. but 5mm is a really small
increment in stem adjustment, and i'm comfortable with that. at any rate,
i hope i am off the hook with you, that i offer my customers the ability
to actually vary their stem height.
> >okay, i'll bite. all bike makers agree that the lower you can make the BB
> >the better, for handling.
>
> Until you put your pedal down in a corner, which is very bad for
> handling. I like to pedal through corners.
you can put your BB wherever you want. i do suspect our BB height, from
the ground, is fairly similar, and as you say, yours might even be higher
than ours, based on what you're saying about cornering. and if it is,
your saddle won't be lower to the ground as a result, and you're right,
this won't affect your headtube length. having 700c in general will, but
BB height won't. i stand corrected.
> > that means that you'd need a considerably smaller
> >headtube just to get where you need to get to be the same as any 650c
> >bike. that's hard to do with 700c.
>
> But the headtube length is chosen as a function of where the top needs
> to be, not just where the bottom starts. It's just not a useful
> measurement in itself, without knowing all the other parameters.
you're right, it is the headtube top. that is precisely what gerard and
i have been saying. that you choose 700c makes this tougher to achieve if
you want your headtube low enough to achieve the position gerard & i are
talking about, but when you get to a particular size it is easily
achievable. this is the same problem, or one of the problems, women have
in having bikes fit to them. you can't get the headtube short enough.
that, along with toe-clip overlap, is the reason everyone's (well, trek,
c'dale lately, and ourselves for the past dozen years) building their
women's bikes 650c front & rear now.
> You see, the difference as I see it is moot because I assume that a
> rider will fit on either a 650 or 700 bike that....
>
> 1) has the same BB height and
> 2) has the same "seat tube height" (measured the same way)
>
> That is, start at the same BB height, measure up a 78 degree seat tube
> to the same "height", extend a horizontal top tube, and it's gonna
> impact the head tube at the same exact place and height, whether that
> head tube houses a 650c fork (in which case the BOTTOM of the HT will
> start lower) or a 700c fork. End result is exactly the same, relative
> to the top of the head tube, which is all that matters. Another way
> to look at it is that a Habanero frame 2.5cm shorter than a QR frame
> (if they're measured c-t of the top tube) with a 2.5cm longer seat
> post extention will be pretty close to identical to a QR in fit,
> assuming they had the same top tube length.
you'll agree that, for the same headtube top, 700c bikes have to have
shorter headtubes than 650c bikes (assuming all other things equal). you
therefore eventually run out of headtube sooner on a 700c. i guess you
can disagree with this statement if you want, or consider it immaterial,
but we find that even with 650c bikes, we really can't build the headtube
any shorter on any bike below 51cm. that is 11cm of headtube, and is as
short as we're comfortable going, for mechanical and structural reasons
not germaine to this post.
> >hey, maybe that's why time trial bikes have had a 650c front for the past
> >generation!
>
> And 24" and 700.... The pros need a radical position to set records,
> that none of us mere mortals should worry much about.
whoa there, boy. they were using these wheels pre-aero bars, when their
backs were not flatter than triathlete's backs right now. and i'm not
talking about simply TTT bikes, where the gap between team riders needed
to be smaller.
> Look at the TT
> bikes the Yurrupean pros use on the road courses, and most of 'em have
> two 700's
well, on the hilly time trials, yeah, when they're using their road race
bikes. i think we can agree that you can use either 700c or 650c (or 24"
or 20" or 17"). 700c is eventually impactful on the smallest size you can
comfortably make a bike if you want a fairly aggressive drop to your bars
without funky stems. i am quite willing to own up to drawbacks re 650c, i
sure would prefer that those who choose 700c to have the same intellectual
integrity, and will admit to the laws of mathematics. you may not feel
that what i'm talking about is impactful on how you build your bikes, and
if this is the case i freely grant you the continued license to build your
bikes 700c, and i will not raise my royalty.
qrman
Dan Empfield
<intern...@cervelo.com> wrote:
> > 1. the seattube, and things backward from it, are the last thing the wind
> > sees; the downtube is in the middle of the bike; i suspect that doing what
> > you can to reconnect the wind is the more important mission.
> >
>
> I don't quite understand this. It's like saying that a convertible will have
> the same fuel economy as the coupe it was derived from, because the front and
> rear are the same and the middle part doesn't matter. This obviously is not
> the case.
well, every analogy eventually breaks down, and yours breaks down a little
sooner. my thesis has been stated quite frequently here, that i think the
first and last things the wind sees on a bike are the most important, and
changing the shape of those things also happens to be the least impactful
on their performance. certainly making a seattube aero, as i stated
above, is the very least important reason why it is an important tube.
it's function as a rear wheel shield is more important, in my opinion, and
i think your P2 does this job admirably. why do i believe this? no good
reason. i just think it's probably true. it seems intuitive. certainly
some bikes, like the lotus, test well with this feature, which might
support this view.
> Furthermore, I think we both agree that a good aero fork and an aero front
> wheel are important. What do these two items do if they are aero? Being aero
> means they don't disturb the airflow much. so behind them, the airflow is
> still pretty nice. And now all of a sudden it is not important anymore if it
> hits something aero or non-aero? Why? If it is important that the undisturbed
> flow hits an aero fork and an aero front wheel, then it is also important that
> the almost undisturbed flow that comes of the wheel and fork hits an aero
> downtube.
i doubt very very much if the air that hits the downtube is almost
undisturbed, since the front wheel, spinning, is directly in front of it.
and yes, we agree that the fork is very important, and the front wheel is
very important. why? because the evidence from a plethora of wind tunnel
testers says it is.
> sorry for all the trouble you went through to explain my implicit statements,
> but the Eyre Tri does not have water bottle bosses on the downtube, for the
> same reason they are not to be found on the P2. Here is my explicit statement:
> Don't use water bottles anywhere on the frame. not on the downtube, not on the
> seattube. Put them behind the seat and/or use a Jetstream or similar system.
> We do have water bottle bosses on the seattube, for those who go on long
> training rides with no aid stations. But I would never suggest to use them in
> a race.
we do agree on this item, then, that if you're going to put water bottles
on your downtube you may as well forget about whatever advantages you get
when making it aero?
> > 5. it has already been established that bikes that really are somewhat
> > more aero, however slightly, from standard frames, often-- or usually--
> > are so because of faired seattubes and either faired or missing
> > seatstays:
> I am not sure I understand this whole point, but it is true that a Softride
> really needs a disc to get reasonable aero performance.
i snipped the bottom part of this because this is the part you get, that a
softride needs a disc. as to the rest of my statement above, remember,
these points are those which are my theses for saying that aero seattubes
(that fair rear wheels) are more efficacious than aero downtubes. my
statement above essentially says that one reason i believe this is because
bikes that have this feature tend to test well, bikes that don't have this
feature tend to test like every other bike (i'm sure your private tests
show different results, these are simply the tests i've seen).
> > 6. it has also already been established by the tester you and i are most
> > familiar with that one particular bike, very "hot" in the previous two or
> > three years, sporting simply an aero downtube and no other aero tube,
> > tested pretty much identically to round tubed bikes; the argument i've
> > heard in response is that this tube was not the "right" aero tube, but
> > really, the shape wasn't bad at all; the aero tube here just didn't work.
>
> I am not sure about which bike and tester you are talking, so it's hard to
> comment on that.
i suspect you do know which bike i'm talking about, but i don't see any
reason to start hammering on somebody else's bike right now, since you can
see how i get hammered for defending you when you hammer c'dale, and how i
get hammered by you even when i'm praising your bikes.
> > the very easiest thing to do is put an aero downtube in a bike. the
> > really hard thing to do is put an aero seattube in it, with corresponding
> > aero seatpost, and a nicely faired downtube that is sucked up pretty far
> > inside the seattube. that's really hard to do.
>
> What do you mean here? The downtube inside the seattube? do you mean combining
> the two into one tube, making it a Lotus style bike?
i'm sorry for my syntax. i'm saying that it is easy to put an aero
downtube in a bike. it is hard to put an aero seattube in a bike (if you
are going to want to use an aero seatpost and cut the tube out for the
rear wheel.)
> Well, even if you don't buy in to the aerodynamics of the Eyre Tri, the bike
> is of very similar weight to any other tri bike out there, and it is stiffer
> in the bottom bracket than any Easton bike I have ever tested.
then you should sell plenty of these fine bikes.
>
> Now if we were to make a bike with a round downtube with the same technology
> (e.g. the differential butting), the bike would be even stiffer. But as it is
> already stiffer than most other bikes, I don't really see the point in that.
> Instead, I prefer to have the aero advantage, and the fact that you don't
> believe in it doesn't slow me down.
go gerard go!
qrman
Mark Linenberg
>
>In all likelihood, Velonews is basing their claims on the testing done by the
>German magazine Tour, which did indeed report that there was little difference
>in the power required to pedal a Lotus vs. other bikes (e.g., Cheetah, Stork,
>GT) around a velodrome at ~45 km/h. As Gerard has pointed out
>previously, however, Tour made some mistakes in their calculations which
>tend to obscure the differences between bikes. Furthermore, Peter Keen has
>presented data in Cycle Sport collected on Boardman himself showing a
>signigicant advantage for the Corima bike that Boardman used in his first
>record compared to a standard round-tubed track bike, and the Corima has been
>referred to by people who have tested it as "a pig in the wind tunnel" - so,
>which do you think is right, Velonew's second-hand extrapolation, or Peter
>Keen's first hand data?
>
>As for Rominger, he went farther on his second attempt at the hour, when he
>switched to a bike made of quite functional aero tubing...
>
The data I posted was from Ulrich Schoberer, and Velonews basically
called him a speed guru with a wealth of knowledge from testing many
top riders for aero postitioning. The tests were done at Boardman's
record speed (I'm assuming ~56km/h), not 45km/h. Was Boardman's
wheel choice and helmet choice the same in both attempts? Also the
article mentions "wind tunnel predictions." A rider was tested in a
wind tunnel with his legs in a coasting position- the wind tunnel
predicted he would need 296 watts to generate a speed of 45kph, when
testing with a SRM was done on a track with the same aero position,
but with his legs pedaling the bike at 45km/h, 373 watts of power were
necessary to go at 45km/h.
I'm not doubting the benefits of aero tubing, but it seems that if you
have a given amount of money- time spent on optimal positioning, wheel
and helmet choice seem to be much more critical than frame tube
designs.
Cervelo Cycles
Dan Empfield wrote:
> with the
> open-to-buy dollars gone, LBS's won't be able to patronize the smaller
> builders. this takes the pressure off the big guys to keep innovating,
> and you get crappy bikes sold be LBS's that don't know what they're doing.
That's the positive scenario. The negative one is that you will have to go to
Wallmart or Toys-R-Us to buy a bike. (This may be too far outside mainstream
knowledge for most rst-ers, but there is quite an uproar in the bike biz about
Mongoose selling to Wallmart in a way that threatens their LBSs).
Gerard.
cog...@grecc1.ab.umd.edu
> The data I posted was from Ulrich Schoberer, and Velonews basically
> called him a speed guru with a wealth of knowledge from testing many
> top riders for aero postitioning. The tests were done at Boardman's
> record speed (I'm assuming ~56km/h), not 45km/h.
Ahh, it was in the Schoberer article! I wondered how I could have missed it.
> Was Boardman's
> wheel choice and helmet choice the same in both attempts?
H***, Boardman's position wasn't even the same for the two hour attempts,
since he used the Superman to go 56+ kilometers. However, that isn't the
comparison (1st vs 2nd hour) that I'm talking about...prior to his first
hour, Keen and Boardman did a lot of experimenting using an SRM, trying out
various things, including the Obree Mk. I position. The data were published
in (among other places, probably) Cycle Sport. The power-velocity curves
presented show a clear advantage to the Corima bike, which, as I said before,
really isn't all THAT aero as such bikes go.
> Also the
> article mentions "wind tunnel predictions." A rider was tested in a
> wind tunnel with his legs in a coasting position- the wind tunnel
> predicted he would need 296 watts to generate a speed of 45kph, when
> testing with a SRM was done on a track with the same aero position,
> but with his legs pedaling the bike at 45km/h, 373 watts of power were
> necessary to go at 45km/h.
So somebody was silly enough to not consider this effect - all that proves is
that there not very sophisticated in their own thinking. (FWIW, everbody I
know and/or know of tests riders in the wind tunnel while they are pedaling -
this includes Team EDS, the AIS, the tests at Texas A&M, the recent Mercury
team tests, Cannondale/Gotti, etc.). But, the whole issue of the external
validity of wind tunnel testing is why we (Jim Martin, Doug Milliken, John
Cobb, Kevin McFadden, and myself) performed and published some experiments.
You can read the full report in J. Appl. Biomech. 14:276-291, 1998, but
basically what we found is that the power requirement as predicted from wind
tunnel measurements agreed on average to w/in +/- 3 W of that measured in the
"real world" using the vaunted SRM.
(Really, Ulrich Schoberer should be quite happy with the results of this
study - not only do the data show that his SRM is as good as a wind tunnel
and a calculator, but also that the SRM is as a good as a Monark ergometer,
since we validated the SRM against that "gold standard" as part of the
testing.)
> I'm not doubting the benefits of aero tubing, but it seems that if you
> have a given amount of money- time spent on optimal positioning, wheel
> and helmet choice seem to be much more critical than frame tube
> designs.
Of course position is #1, and wheels are #2 - that's widely accepted.
However, the role of helmets is still widely debated - John Cobb, who has
probably more experience doing such testing than anyone, doesn't that aero
helmets do anything for you (FWIW, based on his experience John is also
convinced that the "head down - helmet tail up" position is usually FASTER,
contrary to what is generally written. If you doubt me on this, you can call
John, or just check out the pictures of the USPS rider on his website - do
you think they would have bothered wasting time and $$ testing the head down
position that is shown if they knew a priori that it would always be
significantly slower?). But, after you've optimized your position, and have
gotten some aero wheels, then it is time to pay attention to other things,
like the drag of the bike itself, 'cause if you don't you're going to be
giving up about 1 min/hour to people who do...
David W.
> >As for Rominger, he went farther on his second attempt at the hour, when he
> >switched to a bike made of quite functional aero tubing...
> >
> called him a speed guru with a wealth of knowledge from testing many
> top riders for aero postitioning. The tests were done at Boardman's
> wheel choice and helmet choice the same in both attempts? Also the
> article mentions "wind tunnel predictions." A rider was tested in a
> wind tunnel with his legs in a coasting position- the wind tunnel
> predicted he would need 296 watts to generate a speed of 45kph, when
> testing with a SRM was done on a track with the same aero position,
> but with his legs pedaling the bike at 45km/h, 373 watts of power were
> necessary to go at 45km/h.
>
> have a given amount of money- time spent on optimal positioning, wheel
> and helmet choice seem to be much more critical than frame tube
> designs.
Wow, some very techy stuff. But I have one question, Mark. Do you know
if any of the test bikes had water bottles on the tubes? I've heard that
water bottles can negate the effects of aero tubing. Any thoughts based
on what you have read?
David / FEY2K
-proud Alumn of the first Emory Indoor Tri ;-)
Cervelo Cycles
Seth Moore wrote:
> Andy - I talked a friend of mine into a Cervelo P2 last year. Beautiful
> bike. He loves it except for the following points.
>
> 1. Paint is already falling off by the handfuls.
>
We have been working on this problem since last year and our new paint sticks a
lot better.
> 2. Space between rear wheel and seat tube is critical and set up for
> clinchers only. He had to dig up a special spacer system to use a tubular
> disc wheel which was a pain.
>
There is no spacer system required. you can position the rear wheel anywhere in
the drop-out to get the correct spacing. Some people feel awkward wbout not
putting the axle all the way to the front of the slot, but it really doesn't
matter. The quick-release clamping force is more than sufficient to hold the
wheel in place. On top of that, we changed the chainstay length slightly this
year, and it will now fit a tubular wheel with normal size tubular when the
wheel is all the way to the front of the slot.
> 3. He does Ironman triathlons (6th at the Great Floridian) and will
> qualify easily for Kona this year. Only problem is that the bike is killing
> him after 50 miles. Extremely stiff and beating him to death.
I cannot agree with that. Plenty of people do Ironman races on a P2 and like it
for that purpose. Some people even say it's the most comfortable ride they know
(which I cannot agree with either). But the fact is that when people complain
about the comfort of the bike, any bike, it is usually really related to
positioning and not to the frame. for all intents and purposes, the frame only
determines 10% of the comfort. Most of it comes from saddle, wheels, bars, etc.
All double-diamond frames are virtically stiff, no matter what tubing is used.
The structure will take care of this, and there is little that can be done about
it. allthough we still try.
Just as a sidenote, two people I know that rode a Softride because they had back
problems (Graham Fraser (Ironman Canada owner) and Julie Kaplan (women's Masters
40k US record holder), switched to a P2 last year. They both were afraid their
back wouldn't be able to handle it, but both experienced no problems and loved
the fact that it was so much stiffer in the bb. Julie also set a new national
record.
Cervelo Cycles
Mark Hickey wrote:
> If you want to measure based on saddle height, you have to add in the
> seatpost. SO... If you're on a 4" shorter Habanero with a 4" longer
> seatpost, my head tube is shorter than the Cervelo. There has to be a
> realistic way to compare frame of the same "size"... To me, that's
> center to top of the top tube. That produces a constant way of
> determining standover height (when added to BB height, of course).
> This is the critical parameter as to top tube height, and standover
> height.
I agree that this is a good way to do it, I thought you meant to the top of the
seattube which is not a good way. So we agree, measure to the top of the top tube from
the center of the bb. The only thing to be careful about then is that a 54cm frame
will not have a 54cm center-top measurement, but I think that is clear to everyone by
now. I will do some additional measurements this weekend and report back next week,
hopefully (we are moving so it may take a bit longer).
Cervelo Cycles
Dan Empfield wrote:
> maybe we should consider, gerard, another measure, something we might call
> headtube drop (or some similar wording). it would be the difference
> between lines parallel to the ground from the seattube top to headtube
> top.
>
> i think that would cover it. it doesn't matter where your BB is, your
> butt is where your butt is vs the headtube top. if you drop the BB, you
> shorten the headtube to compensate, right?
>
> this assumes that everybody's seattube top stops at a place common in the
> industry (i.e., people 6' tall ride 58cm or 59cm bikes, people 5'5" ride
> 48 or 49cm bikes). that is really the only reason we extend our
> seattubes. otherwise we'd cut them off low, like MTB bikes. it's just
> too confusing to explain that to people, though.
>
Well, we do cut them, not because we want to confuse people (although we do on
occasion, but because we think it is a better solution to avoid frame failure in
that area, as I pointed out earlier). Anyway, this means that your measurement
won't work if people want to compare QR and Cervelo. I would suggest the virtical
distance between bb and the top of the headtube. The top of the headtube could be
replaced by the top of the top tube which is similar, except that details such as
our minimalist headtube extension over the top tube won't show up, and it does
effect how low the bars can go.
> >If Cannondale dealers are going to set-up their customers correctly
> > this year, the sales of Look Ergostems should be booming. Look is therefore
> > rated a strong buy :-).
>
> god i hope so. i've got a bucketload of these i'd like to unload cheap.
>
ditto. I think people are finally unravelling our scheme here. We're not out to
sell bikes, we want to get rid of our Ergostems. :-)
Stephen Fleck
and respect their opinions on bike design and fit very highly. I have enjoyed
this discussion in a big way.
Some observations from a guy who has been in the sport a very long time:
1.Regardless of what the bike is or is made of, its aerodynamics and other
engineering, the fit of the rider to the bike is paramount.
2.Riding style and fit seems to be very individual. Not unlike the uniquness of
someone's running gait.
3. Extreme aero positioning, while yeilding great numbers in the lab is often
not practical or comfortable for extended periods while on the bike in real
race/training situations.
4.Some of the top cyclists and cycling triathletes in the world have great
positioning on the bike. Some others, Indurain, Spencer Smith, Jurgen Zack come
to mind, do not, when in TT mode but they still can fly like the wind. Perhaps
positioning for power is important.
5. In a perfect world we would all have two bikes a road bike and a tri/TT bike.
However, the reality is that most people can only afford one, so comprise is the
order of the day. I have ridden retro-fitted road bikes all my years as a
triathlete(16+) and have never had any problems with handling, comfort or
performence. When set up properly for me the bikes, climb and corner well. They
behave themselves in the pack when training and when I am fit they can go under
60min for 40K or 5:00 hrs for an Ironman bike leg.
Road or tri bike? Handle bar set up? Head tube length? It's an individual call.
Whatever one does, take the time to learn the ins and outs and get set up
properly nad the train like hell.
Now back to you, Gerard and Dan. Two guys who really know what they are talking
about.
Steve "I just ride the bikes" Fleck
Mark Linenberg
>However, that isn't the
>comparison (1st vs 2nd hour) that I'm talking about...prior to his first
>hour, Keen and Boardman did a lot of experimenting using an SRM, trying out
>various things, including the Obree Mk. I position.
The article talks about the obree "egg" position as well. "Before the
UCI outlawed the G. Obree egg position, the German Pursuit team
practiced with the position and SRMs. Using the obree position during
training, they rode a 4km pursuit in 3:55 (five seconds faster than
the current world record). In an optimized boardman like position on
aero bars, a rider must produce 461 watts to ride at 50 km/h. In
Obree's position, the same ruder must put out 421 watts to ride
50km/h.
> the role of helmets is still widely debated - John Cobb, who has
>probably more experience doing such testing than anyone, doesn't that aero
>helmets do anything for you (FWIW, based on his experience John is also
>convinced that the "head down - helmet tail up" position is usually FASTER,
>contrary to what is generally written. If you doubt me on this, you can call
>John, or just check out the pictures of the USPS rider on his website - do
>you think they would have bothered wasting time and $$ testing the head down
>position that is shown if they knew a priori that it would always be
>significantly slower?).
FWIW: I saw Greg LeMond speak at Richardson Bike Mart in Richardson,
TX last October. I asked LeMond about his aero advantage during his
epic battle against Fignon in 1989. LeMond, said that the Giro aero
helmet actually slowed him down approximately the same amount that his
aerobars helped. When LeMond time trials, he often would look down
toward his stem, instead of up the road. Looking down, caused his
helmet to stand upright and act like a giant break. LeMond said that
wind tunnel testing was used to confirm this after the tour.
But, after you've optimized your position, and have
>gotten some aero wheels, then it is time to pay attention to other things,
>like the drag of the bike itself, 'cause if you don't you're going to be
>giving up about 1 min/hour to people who do...
At what speed? Was the testing real world with an SRM or with a wind
tunnel and just extrapolated? And if the testing was done with a
track and SRM how easy/reliable is it set up a rider position exactly
from bike to bike? What was the comparison bike- frame/fork? What was
the aero bike- frame-fork?
Mark Linenberg
>if any of the test bikes had water bottles on the tubes? I've heard that
>water bottles can negate the effects of aero tubing. Any thoughts based
>on what you have read?
>