Latest tire rolling resistance data from Al Morrison
JV
http://jv-cycling.blogspot.com/2010/04/latest-tire-rolling-resistance-data-is.html
Now who is gonna send him some wider tires, or rims, to test?
Cheers,
JV
Jim Verheul
Keep in mind that aerodynamically, on a 19-20mm wide rim, tires fatter then 20-21c are slower, and the improved rolling resistance cannot make up for that as you go faster. It only gets worse. If you put the fatter tire on a deeper, and wider, rim, that combination is faster period. The wide rim also reduces lateral tire deflections, making it handle better too. I have liked slightly fatter tires (25-28c) for decades but would not run them in events where I was trying to go fast, until wider aero rims came out. I see the great innovation here as the availability/use of wider road rims, especially aero ones. Vroomen mentions the wider rims too.
Also keep in mind that once you go to a ~23 mm wide rim, your tire will be wider than its nominal size when inflated. This means if you used to like like 25c tires on 19mm rims, you might now like 23c tires on 23mm rims, as the tire measures 25mm wide now! Similarly a 25c tire will measure ~28mm on a 23mm wide rim. As you point out, its hard to find fast supple casings in fat tires. But with a wide rim, you can now potentially move to one size narrower in your tire, which will likely open you up to the more of latest in fast tire technology. There are a lot of top end 23c tires available in 25c, that will now measure 28mm wide.
You do have to get over the weight issue though, and some are still hung up on that. A wider tire and rim will be a bit heavier. Light wheels and tires still feel fast. There is a difference between what feels fast and what is fast though, in steady state riding. I am still waiting for a cheap 3-32mm deep allow rim that is 23-24mm wide. The only one now is the Velocity Chukker, but its 650g! Thats more than a little bit heavier! The up side is I'd use a rim that heavy with 24 spokes, maybe less, if its available.
Yes, lower pressures on rough roads, but still enough not to pinch flat, is usually faster. Tire deformation (hysteresis) wastes energy, but your bike and you being deflected all over the place costs much more. Throwing up or not being able to eat from all the vibration is even slower! However, there are times that a hard tire can actually skim across the tops of the bumps in the surface. It takes just the right surface (closely regularly spaced bumps) and speed (high). On smooth pavement, harder is still faster.
Still happy with Hed Jet C2s and 23c tires,
JV
How much more testing do we need? It seems like the pro teams are getting on board, now that Bicycle Quarterly has shown the importance of suspension losses, even on smooth roads.
Seeand scroll down to the headline "Wheels and Tyres: Fatter is the way to go." I especially like the sentence about retraining their mechanics not to overinflate their tires. They now run less than 75 psi for some rider in Paris-Roubaix... (Of course, Mr. Vroomen still thinks 25 mm is the optimum width, because wider tires simply don't fit inside the frames he sells.)Even Lennard Zinn has changed his tune, seeIt appears that the fact that wider tires are faster - even at racing speeds - finally is gaining widespread acceptance. At lower randonneur speeds, the advantages of wider tires are even more pronounced.Of course, as our tests have shown, tire construction is more important than width. Unfortunately, many (most) wide tires are intended for hybrids and are not optimized for performance. A narrow racing tire still is faster than a wide puncture-resistant hybrid tire...But fortunately, the offerings of wide high-performance tires are increasing all the time.Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
Jonathan
(like Jan's roll-down tests), please let me know!
I just switched from Continental CityContacts (406-32) to Greenspeed
Scorchers (406-40) and dropped the pressure down from around 90psi to
60psi on the rear wheel. Amazing difference in ride comfort, and I
don't think there was any impact on speed (I'm still slower than
many).
-Jonathan
Cleveland, OH
Jim Verheul
At 12:04 PM -0700 4/7/10, Jim Verheul wrote:
Keep in mind that aerodynamically, on a 19-20mm wide rim, tires fatter then 20-21c are slower, and the improved rolling resistance cannot make up for that as you go faster.
Do you have actual measured data for that?
No, just having looked at a lot of wind tunnel data on the net, and engineering intuition. Can you share your data? I don't think I've seen it. It would be very interesting.
When we tested 25 mm tires vs. 30.5 mm tires in the wind tunnel, with a rider on the bike, the difference was within the noise (statistically not significant)... We used the same narrow rim for both. Nobody really knows the aerodynamics of wider tires - the only other tests I have seen didn't include the rider. Without the rider, you get cleaner data, but the tests are pretty meaningless, as the rider's legs churning do affect the airflow around both wheels greatly.
Good point. On your bike, and the majority of randonneuring bikes, the rider is more of a factor in wheel aerodynamics than one mine. ...and more of an aerodynamic factor overall too.
I don't know how fast you go, but even at about 20 mph, rolling resistance offers the biggest gains, because it's so easy to change. Sure, if you could decrease your wind resistance by half, that would be great. But you can't. Even a full aero tuck only gains you 37%. On the other hand, switching from a slow tire to a fast tire easily can halve your rolling resistance, or more.
37% reduction in frontal surface, or CDa, or drag at a certain speed? Perhaps then the aero biggest gain is to go to a reclined recumbent? ;-) I wonder by how much though. The slower you are the more the lower Crr tires will help you, compered to aerodynamic improvements.
The big question that nobody has addressed is where the benefits of wider tires tail off. We know for sure that 25 mm is faster than 23, but is 30 faster than 25? Is 40 faster yet? What about 60 mm? We are working on this...
That is a good one to go after. You have a tunnel for this? One of my data gaps is at what apparent wind angle do aero wheels stall out and cause more drag than box section rims. Most data I have seen stops at 20-30 degrees yaw angle. So somewhere between that and 95ish degrees, its slowing you down. This is not common in short fast TTs, but might make a big difference on the Great Plains in RAAM.
On the flats I spend most of my time at 20-24mph with no wind.
Cheers,
JV
Kevin Foust
Interesting bit of testing there. As an innately curious member of the species...
I know it isn't your work, however I thought perhaps you could help... I can't find any information on the test method other than what is in the .pdf file. Can you give me a link to a description of the test method? Also, how is Crr calculated?
Later,
Kevin
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J.T. Conklin
> Of course, as our tests have shown, tire construction is more
> important than width. Unfortunately, many (most) wide tires are
> intended for hybrids and are not optimized for performance. A narrow
> racing tire still is faster than a wide puncture-resistant hybrid
> tire...
I think *this* is why it would be useful for a larger selection of
wider tires to be represented in the DB. Not for comparing narrow
vs. wide, but for comparing different wide tires. eg. Rivendell Jack
Browns vs. Grand Bois Cypres vs. Marathon Supremes vs. Vittoria
Randonneurs vs. ...
--jtc
--
J.T. Conklin
Jim Verheul
However, you can find many of the equations here:
http://www.recumbents.com/WISIL/MartinDocs/Validation%20of%20a%20mathematical%20model%20for%20road%20cycling.pdf
http://www.teamnaturespath.com/Files/Tires/Tire_Data.pdf
If you have specific questions, Al is on the forums at http://biketechreview.com/forum, and Tom is on the Slowtwitch forums:
http://forum.slowtwitch.com/Slowtwitch_Forums_C1/Triathlon_Forum_F1/
Cheers,
JV
prestonjb
>
> Even Lennard Zinn has changed his tune, see
>
>
where in the above does he say he changed his tune?
prestonjb
> I just switched from Continental CityContacts (406-32) to Greenspeed
> Scorchers (406-40) and dropped the pressure down from around 90psi to
> 60psi on the rear wheel. Amazing difference in ride comfort, and I
> don't think there was any impact on speed (I'm still slower than
> many).
>
sounds like snake-bite territory to me
Steve Palincsar
For a 40mm tire? I don't think so. I run 40mm 650B Hetres at 50psi and
get no snakebites.
Charles Lathe
Here is a quote attributed to Lennard Zinn relating to tire pressure.
The date is 3.23.5.
"It entirely depends on the road surface. If it is chip sealed and you
ride with a 19mm tire at 140psi, there is no question that you will
have higher rolling resistance than with a 23mm pumped to 90psi
(assuming that both are high quality high-thread-count tires). Every
time you deflect the bike and rider up and back, it costs you energy,
as opposed to absorbing the gravel hunks into your tire. This is the
same reason that suspension makes a mountain bike, car or motorcycle
faster on rough terrain. If you are riding on a smooth track, by all
means use a 19mm tire and pump it up to super-high pressure."
And another from the same discussion:
"When you ride a tire at 170psi, the bike feels really lively and
fast. That is because you are being bounced all over the place by the
surface roughness of the road. However, every time you are bounced,
energy you applied to the pedals to get you up to speed is lost. Also,
you have less control of the bike, so it feels like it is going
faster, even though it isn't. Ever notice how driving down the highway
at 75mph in an old Jeep feels crazy fast, and you can cruise smoothly
along at 100mph in a nice Saab or BMW and feel like you are going
maybe 60mph unless you are looking at stationary objects passing by?
There is simply no question about it; rolling resistance tests
conducted with bicycle tires rolling over surfaces akin to normal road
surfaces always indicate the lowest rolling resistance at pressures a
lot closer to 100psi than to 170psi! Years ago, for example, I saw
results like this at the Continental tire factory. I was told of
similar results at a number of other tire factories I have visited."
These quotes come from a discussion about tire width and pressure on
bikeforums.net. (http://www.bikeforums.net/archive/index.php/
t-94682.html). On casual inspection, they seem to imply that Lennard
had this stuff pretty well figured out some time ago. I must say I am
a Zinn fan. He began his time at The Colorado College a couple of
weeks after I finished. With the notable exceptions of Nina and
myself, Colorado College is not known for graduating dummies.
Regards, Chuck Lathe
Franklinville, NC
prestonjb
> > sounds like snake-bite territory to me
>
> For a 40mm tire? I don't think so. I run 40mm 650B Hetres at 50psi and
> get no snakebites.
wait sorry my bad... i missed that u switched from 32 to 40mm... ok
60psi is not so bad then
prestonjb
>
> Zinn used to say that higher pressures were faster, and that narrow
> tires were faster because they could be ridden at higher pressures.
and he is right !
>
> Now he gives a pretty good summary of suspension losses... which are
> the reason why super-high pressures aren't any faster on real roads,
> as we have said since we first started testing tires on real roads
> with a real rider on the bike more than 3 years ago.
>
and u are right.
> That Zinn acknowledges that wider tires, run at lower pressures, can
> be faster, is a big and welcome change.
>
not sure he said he has changed.
>
> Disclosure: Vintage Bicycle Press sells 23 mm wide rims, but they
> aren't exactly aero-profiled.
23 seems mighty wide to me... i run 21s on my mountain bike and they
seem darned wide!
prestonjb
implies
prestonjb
jack!
>
> "Rolling resistance does decrease theoretically with any increase in
> pressure." and "An overinflated tire will have slightly less rolling
> resistance."
>
> We've learned a lot since Sheldon wrote this, and I am glad that Zinn
> was among the first to realize this.
>
i think no one ever said it has to be max pressure no way anything
else and ive been doing this since 1982!
Steve Palincsar
Actually, 60's pretty high for a genuinely 40mm wide tire.
prestonjb
in the paragraph @@@@@@@@directly above this one@@@@@@@@@ sheldon
specifically says that high pressures removes the advantages of the
pneumatic tire specifically "traction" which in what i can see is the
other major player in an equation of your @@real world@@ measurements
as ive seen cited...
so his statement below @@@is@@@@ correct and is not wrong even in this
discussion as long as @@@@you @@@@ include @@@@his entire @@@
statment and not @@@your@@@ selective editing of what sheldon said!!!!
gesh man.... set aside... i got a lot better things to do than watch
ur politics!
>
> "Rolling resistance does decrease theoretically with any increase in
> pressure." and "An overinflated tire will have slightly less rolling
> resistance."
>
> We've learned a lot since Sheldon wrote this, and I am glad that Zinn
> was among the first to realize this.
>
> Jan Heine
> Edits.com
Bill Gobie
one, or do whatever it takes to chill yourself out.
This attack on Jan is uncalled for and thankfully unusual on this list.
Bill Gobie
David Lach
preston I'd say you're the one who should put the beer down, or get one, or do whatever it takes to chill yourself out.
This attack on Jan is uncalled for and thankfully unusual on this list.Bill GobieOn Apr 9, 2010, at 4:56 PM, prestonjb wrote:
jan u are full o beer or personal self promotion or something sick..in the paragraph @@@@@@@@directly above this one@@@@@@@@@ sheldonspecifically says that high pressures removes the advantages of thepneumatic tire specifically "traction" which in what i can see is theother major player in an equation of your @@real world@@ measurementsas ive seen cited...
so his statement belo s not wrong even in this
discussion as long as @@@@you @@@@ include @@@@his entire @@@statment and not @@@your@@@ selective editing of what sheldon said!!!!gesh man.... set aside... i got a lot better things to do than watchur politics!
pressure." and "An overinflated tire will have slightly less rollingresistance."We've learned a lot since Sheldon wrote this, and I am glad that Zinnwas among the first to realize this.Jan HeineEdits.com
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Old5ten
I wholeheartedly agree with Preston! There is no place on this forum to slander people who've done so much for cycling as a whole.
It is one thing to make a group such as randon aware of research that one is conducting, even if it is downright lame and ludicrous that the results can't be published electronically! It is a whole different thing to be pompous about it and at the same time discredit others.
I appreciate good research, but protocol and results should be available freely, subject to peer review, and be confirmed independently - ALL without the unnecessary finger pointing!
Elmar Stefke
DemostiX
smaller 26' wheel, which usually comes with tires that are wider in
diameter.
Looking at tandems, and specifically at the experience of a major US
builder, Co-Motion, I was surprised to find this:
"We have found that many new tandem riders buy inexpensive
first tandems with 26" wheels, hoping to enjoy some of the versatility
that they offer. Very often however, they can become disenchanted.
They find it difficult to keep up with others riding 700C tandems on
group tandem road rides. We have noticed the same effect on tandems
that are otherwise virtually identical. It just seems more difficult
to maintain high speeds on a 26"-wheeled tandem. If you're interested
in fast road riding, and you don't need the flexible sizing of the
PeriScope or off-road ability of our Mocha, we'd recommend 700C
wheels."
Now, this may reflect non-comparable tires, the 26" ones in most
riders' experience being stiff-walled and heavy. And it would be
interesting, Jan, if you were to interview one of the principals at Co-
Motion 300 miles south of you, to find out if high quality 26" (or
650Bs) have been tried by some of their clients. I'm particularly
interested, because the shorter wheel would suit me better as a tandem
captain.
Elsewhere, another major tandem mfg, Santana, has closely observed
empirical observations about contact patches of 26" (and likely
fatter) vs 700C (and likely narrower) tires. Heres' a paraphrase of
Santana's McCready:
"If they both corner at the same speed, is either tandem bicycle wheel
size more efficient? Yes. Because of its smaller diameter, the 26"
tire is forced to deform more to apply its equal-area-yet-fatter
contact patch to the ground. When we put the same weight on both bikes
it's easy to observe more "bulge" in the sidewall where the 26" tires
meet the ground. Greater tire deformation (sidewall flex and tread
squirm) equals greater internal tire friction; the leading cause of
rolling resistance."
Harry Travis
New Jersey, USA
On Apr 9, 10:18 pm, Jan Heine <hein...@earthlink.net> wrote:
> At 5:47 PM -0700 4/9/10, David Lach wrote:
>
> >Circumstances differ. People have to apply evidence to their
> >circumstances. Changing your mind is intelligent, not a sign of
> >failure.
>
> I apologize for my somewhat off-the-cuff remark that "Lennard Zinn
> changed his tune." I didn't mean to say that he was wrong before, or
> anything like that. I have great respect for his work.
>
> All I wanted to say is that now, in 2010, a long-disputed idea is
> gaining mainstream acceptance: that wider tires - even when run at
> lower pressures - can be as fast or faster than narrow, high-pressure
> tires. Perhaps this idea isn't all that new, but most of us used to
> believe that higher pressures were faster, period. We ran lower
> pressures for comfort and better traction, but believed that we were
> giving up some speed in the process. Sheldon summarized the consensus
> on the issue when he wrote the page I quoted. Back then, that was
> correct to the best of most of our knowledge.
>
> When we did our first tire performance tests, we were very surprised
> to find that tire performance leveled off at a not very high
> pressure. Higher pressures weren't faster. For tubulars, they
> actually were slower. This was not what we thought we'd find... but
> it was real, and statistically significant after we did all the
> analyses. Since it was not what most believed then, it is satisfying
> to see that others are now agreeing with us. (And no doubt, some have
> known this all along.)
>
> Anyhow, I appreciate anybody who isn't rigid in their beliefs. New
> evidence changes things - just see the latest Bicycle Quarterly,
> where we found that 650B isn't the only tire size that is useful for
> wide tires. In fact, we rather liked a 26" setup we tested... Who
> knows what will be next? If we want to move forward, we have to keep
> an open mind.
WillemJ
where and under what conditions does the advantage of the wider tyre
tail off to become a disadvantage? For that, I think we need tests of
properly wide tyres compared to the same or almost the same tyre but
of a narrower size. I can think of two interesting pairs. The first
would be a direct comparison between the 650B 32 mm Grandbois Cypres
and their 42 mm Hetre. The second pair would be a standoff between the
ETRTO 559 Schwalbe Kojak in 35 mm and 50 mm form factors. Both
comparisons eliminate tyre constuction as a variable. In both cases I
would love to have an intermediate size as well, but the only quality
tyre where that would be possible (as far as I know) would be the
rather heavier ordinary Schwalbe Marathon, available in 26x1.50,
26x1.75 and 26x2.0, and in six ETRTO 622 sizes from 25-47 mm.
My curiosity partly stems from my own less controlled experience. I
mostly have Panaracer Pasela TG 26x1.75 tyres on my loaded touring
bike. These are nice and pretty fast on smooth surfaces, and their
relatively low weight makes them nice to climb with. On anything
rougher, however, the far heavier 50 mm Schwalbe Big Apple seems
faster (and way more comfortable).
The issue of circumference is also interesting, but a different one,
and possibly irrelevant for many: if fat tyres turn out to be faster,
622 wheels may be too large for many smaller riders. This is already
the case with loaded touring bikes that have clearance for fat tyres.
Willem
Dodger
Review forum. My post and the response from AFM (Al Morrison, the guy
who did the original testing) is posted below. If you can't get that
far he says, "In general I'd say that for the same model of tire the
wider size will roll better assuming equal mileage. Of course the
wider tire will probably have more aero dynamic losses so there is a
trade off."
To my knowledge he has no axe to grind with this, or any other board,
nor has he been drinking. At least as far as I know. And I don't know
if he subscribes to BQ :)
I hope everyone has some great rides this weekend.
dodger wrote:
It looks to me, based on the .csv file, that the 'fat' tires are
faster than the 'skinny' tires - at least the same tire by the same
manufacturer. This holds for 7 out of 10 clinchers (with two having no
difference), and 4 out of 5 tubulars. Note that the difference is
greater than the std dev.
Any idea at what point in a climb weight become more significant than
Crr? Or in a jump? More to the point, my analysis is that it makes
sense to go with 25s instead of 23s or skinnier to minimize Crr. Am I
off-base with this conclusion?
AFM wrote:
I haven't taken the time to find all the examples but in some cases
you might be comparing used skinny tires with miles on them to new
fatter tires with no miles on them. In general I'd say that for the
same model of tire the wider size will roll better assuming equal
mileage. Of course the wider tire will probably have more aero dynamic
losses so there is a trade off.
On Apr 7, 12:14 pm, JV <jverh...@alumni.usc.edu> wrote:
> .....and some observations be me
>
> http://jv-cycling.blogspot.com/2010/04/latest-tire-rolling-resistance...
Dodger
didn't get a direct answer. I realize I didn't ask as precise a
question as I *should* have. Anyway, on the other two questions (re:
climbs and jumps) I got this response:
written by kraig, April 09, 2010
Any idea at what point in a climb weight become more significant
than Crr?
This question is a real can of worms! smilies/smiley.gif It really
depends on the specifics of the comparison you are wanting to make,
and to generalize things would really be a disservice to you, I think.
I think it would be tough to outperform (hey, keep in mind that bike
racin' ain't a math problem, eh? smilies/wink.gif ) a clincher
veloflex record 20mm during a hillclimb (well, at least the VF record
I have tested on my own rollers). That sucker is light, low Crr, and
narrower than 25mm.
Here's a link where you can play out all sorts of scenarios using
whatever assumptions/data you'd like:
http://www.analyticcycling.com/ForcesSpeed_Page.html
Don't forget that "on road/real life" crr is not necessarily the same
as what is listed on Al's chart - especially for the lower speed
hillclimb situation you appear to be interested in.
Or in a jump?
You might find this article of interest when it comes to "jumps":
http://biketechreview.com/reviews/wheels/63-wheel-performance
More to the point, my guess is that it makes sense to go with 25s
instead of 23s or skinnier. Am I off-base with this conclusion?
For hillclimb stuff, I reckon you've got the right "big picture"
things to focus on...mass and crr. Aerodynamics of the tire play less
of a role in this hillclimb type of effort than they might here:
http://biketechreview.com/aerodynamics/tires
...but tire aerodynamics can still play a role even on a net elevation
gain type of effort. So, if your assumed crr is equal, I'd go with the
narrower and lighter option.
Great questions, Dodger! Happy to address any follow-ups you might have
prestonjb
i just dont like to see someone say that soneone else has changed
their tune and cites an article which does not contain any such
inormation... if jan had post the before and after (and has not yet
posted the before) or had zinn stated something in the after that
implies he has changed his tune....
and i was willing to let it go when the posts from bike forum were
presented up until i actually had to see that sheldon was saying what
jan had said and @was shocked that the line right above@ what jan had
cited contained the statements reflected here indicating that he
indeed understood the differences of tire pressures and road surfaces,
etc al...
and reading that makes me wonder why jan @always@ takes the approach
that everyone else is wrong...
all i have to do now is say "i dont see the point in using
fenders" (and im sure he will only cite the stuff in quotes and say
that im against fenders)
prestonjb
wall movement but not below 40psi when not doing sprints w these
monsters!
WillemJ
technology, and casing construction in particular. In the old days it
was hard to make a wide casing that could stand up to some pressure.
If you wanted to contain that much air under pressure you had to make
a sturdy stiff (and thus slow) casing. Technology has moved on, and
now mass produced casings for wider tyres can be pretty flexible and
light.
Anyway, I think the research published in BQ suggests very strongly
that if Grandbois were to produce an ETRTO 622 37 mm tyre it would be
faster than their current 31 mm one, and almost certainly so on bad
road surfaces. And all the more so for heavy riders. If a 37 mm Pasela
can be faster than a 31 mm Grandbois, what would a 37 mm Grandbois
achieve? This also has important consequences for randonneur frame
design. On many rando bikes about 31 mm is the maximum tyre width that
will fit with 57 mm drop brakes. It may well be that the new Tektro 73
mm drop brakes should become the design standard for ETRTO 622 rando
frames.
And as I said in my previous post, it would also be interesting to see
if there are any potential gains beyond this. I have seen a number of
tests by Dutch recumbent riders where the ETRTO 559 50 mm Schwalbe
Kojak proves to be faster than the 35 mm. If 50 mm tyres (mostly some
45 mm in reality) are indeed faster still, this would mean that for
many riders a 622 wheel would be too large for a comfortable frame
geometry. I for one would love to try a 559-45 or even 50 real mm
Hetre.....
Finally, I would like to remind US riders of the work done by Gerrit
Gaastra (the son of the Koga Miyata founder) and his IDWORX brand. He
was the pioneer who persuaded Schwalbe to resurrect the balloon tyre
concept and develop the Big Apple tyre. He also developed a whole
family of very upmarket touring bikes around the idea. They have been
very succesful.
Willem
Bill
I'm currently have a set of wheels with Mavic open pro rims.
What I would like to know is how wide of tire can I put on these rims.
Would a set of 32mm tires work?
Thanks in advance
Bill
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Jan Heine
Sent: Saturday, April 10, 2010 11:51 PM
To: WillemJ; randon
Subject: [Randon] Re: Latest tire rolling resistance data from Al Morrison
At 2:47 AM -0700 4/10/10, WillemJ wrote:
>I remain interested in the larger discussion of optimum tyre size:
>where and under what conditions does the advantage of the wider tyre
>tail off to become a disadvantage?
That is indeed the big question. Of course, it depends on the road
surface. I don't think anybody knows exactly. Mr. Vroomen says that
25 mm is the optimum for most roads, but of course, 25 mm also is the
maximum size that fits the bikes he sells.
The Grand Bois Cypres is available with the same casing and same
tread thickness in 25.5, 28.5 and 31 mm (actual widths). We tested
both the 28.5 and 31 mm, and the results were indistinguishable.
However, the test runs weren't back to back, so there is more
potential for noise. We hope to do a back-to-back test eventually, so
we can see whether the performance really tails off already at 28 -
30 mm.
Similarly, wheel size: While it's intuitive that larger wheels roll
better over bumps (see the Co-Motion quote somebody else posted), our
results indicate that on average backroads, it isn't a factor. We
tested Grand Bois 31 - 622 mm (700C) tires back to back with 32 - 584
mm (650B) tires, and the speeds were indistinguishable. If there is a
speed difference, it's small compared to the other factors. I suspect
that many 26" tandems run commuter tires that roll slowly, and so
they can't keep up with 700C tandems on racing tires...
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com
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WillemJ
recommendations are less restrictive. See
http://www.schwalbe.de/ger/de/technik_info/reifenmasse/?gesamt=7&ID_Land=1&ID_Sprache=1&ID_Seite=12&tn_mainPoint=Technikfor
a table. That said, wider tyres on narrow rims ask for lower tyre
pressures if you do not want to blow up your rim, and they may feel a
bit mushy.
Willem
> Seattle WA 98121http://www.vintagebicyclepress.com
>
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WillemJ
Willem
On Apr 11, 3:54 pm, WillemJ <willem.jong...@gmail.com> wrote:
> Views on this have been in flux in recent years. The new ETRTO
> recommendations are less restrictive. Seehttp://www.schwalbe.de/ger/de/technik_info/reifenmasse/?gesamt=7&ID_L...
Stephen Whiteman
I've run nominal 35 cross tires on OP rims over hundreds of miles of dirt roads, mostly Class 1 or 2, but even stretches of Class 4, without even a flat. Until this week, I was a proponent of the harder-is-better school, too, so I did it with fairly high pressures.
stephen
---
In the brave new world, all scholarly questions will be resolved by crowd sourcing. (Michael Lee)
WillemJ
tested. Still, I do have a hunch that a 37 mm Grandbois may bring
additional speed benefits, or at worst be about equal to a 32 mm
Grandbois - but still be more comfortable, and with better handling on
gravel roads. I guess one could approximate this by comparing a 32 mm
Pasela and a 37 mm Pasela.
As for flexible ETRTO 559 tyres, I can only report my extremely
positive impression of riding 50 mm (nominal) Big Apples on rough
roads. Of course this 26 inch loaded tourer is not a rando bike, and
with a 135 mm wide Rohloff hub it does not have the very narrow Q of
the TA ProVis on my faster bike. However, its TA Zephyr cranks are not
known for a very wide Q either, and there is plenty of clearance with
the relatively slender Deda chainstays. I had a look and in fact even
a Pro Vis with a bottom bracket that gives the correct chainline for a
Rohloff hub would have enough chainstay clearance.
Keep up the good work - I look forward to receiving BQ of Spring
2010.
Willem
On Apr 11, 4:23 pm, Jan Heine <hein...@earthlink.net> wrote:
> At 12:59 AM -0700 4/11/10, WillemJ wrote:
>
> >Anyway, I think the research published in BQ suggests very strongly
> >that if Grandbois were to produce an ETRTO 622 37 mm tyre it would be
> >faster than their current 31 mm one, and almost certainly so on bad
> >road surfaces. And all the more so for heavy riders. If a 37 mm Pasela
> >can be faster than a 31 mm Grandbois, what would a 37 mm Grandbois
> >achieve?
>
> The 37 mm Pasela was faster than the _25 mm_ Grand Bois on rumble
> strips. Now that is an extremely rough surface. We only used it to
> show how great the suspension losses could be. We didn't test the 31
> mm Grand Bois on the rumble strips.
>
> On our average backroad surface, the 31 mm Grand Bois was faster than
> the 37 mm Pasela, but that may be due to the more supple casing of
> the Grand Bois.
>
> >And as I said in my previous post, it would also be interesting to see
> >if there are any potential gains beyond this. I have seen a number of
> >tests by Dutch recumbent riders where the ETRTO 559 50 mm Schwalbe
> >Kojak proves to be faster than the 35 mm.
>
> To complicate things further, on a recumbent, the suspension losses
> may well be greater than on an upright bike, because you sit on a
> recumbent, rather than be suspended by the articulations of your
> ankles, knees and elbows.
>
> >I for one would love to try a 559-45 or even 50 real mm
> >Hetre.....
>
> That would be a nice tire to try! However, fitting such a wide tire
> into a bike with a relatively narrow crank tread (Q factor) would be
> difficult.
Veronica Tunucci
line. Can you help?
I'm a 5'4" cyclist and weigh 125lb and ride a bike that weighs 17lbs.
Assuming all the road, weather, my strength/power conditions are all equal,
what would be the difference in mph if I changed the tire width:
I rode first test on 19mm wide Mavic MA-2 rims and one of your best tires
tested in 23mm at optimum tire pressure (assume an average speed of 13mph
over 100 miles).
Then rode the second test on 19mm wide Mavic MA-2 rims, 25mm tires, all
other factors being equal, what would my average speed increase to?
Then rode the third test on 19mm wide Mavic Ma-2 rims, 28mm tires, all other
factors being equal, what would my average speed increase to?
Thank you,
Veronica
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Jan Heine
Sent: Sunday, April 11, 2010 7:29 AM
To: Bill; 'WillemJ'; 'randon'
Subject: RE: [Randon] Re: Latest tire rolling resistance data from Al
Morrison
At 7:45 AM -0500 4/11/10, Bill wrote:
>With all this talk of wider tires I have a question.
>I'm currently have a set of wheels with Mavic open pro rims.
>What I would like to know is how wide of tire can I put on these rims.
>Would a set of 32mm tires work?
>Mavic quote 19-28 mm recommended tyre width.
I have been running 31.5 mm wide Grand Bois Cypres tires on 19 mm
wide Mavic MA-2 rims (roughly the same width as Open Pro) for years.
Many 650B riders have been running 41 mm tires on 23 mm rims, some
even on 19 mm rims. I don't know of anybody who has experienced
problems due to the narrow rims. (Mountain bikers also often use rims
much narrower than their tires.)
So even though Mavic doesn't recommend it, you shouldn't have a
problem with 32 mm tires on 19 mm rims.
That said, I plan to relace my wheels with 23 mm wide rims, as the
rims are worn thin, and for the wider tires, I do prefer wider rims.
Ken Freeman
I see these on-line bike groups as learning organizations (well, organization is quite a loose term) in which discussion helps to determine a rational consensus on what is right. We only really care about aero versus rolling because we want to know what measures will in reality improve our cycling performance. It doesn't matter if Lennard stated he changed his mind. New evidence has been appearing for perhaps 15 years now, and it's resulting in some of us thinking back through the theory we have read or applied over the years, such as Sharp and Wilson.
It's indeed to Lennard Zinn's credit (and many others deserve this plaudit) that he is continuing to take in and analyze emergent facts in cycling, even though he is now challenging conventional wisdom.
Maybe we need to consider carbon with the same attitude as Lennard ... ?
Hi fellow randonneurs:
I think it would be good for people to concentrate on what is right, and in what circumstances, not who is right.Comments about when people began or stopped thinking a certain way just deter people from appropriately modifying their views based on the available evidence.Circumstances differ. People have to apply evidence to their circumstances. Changing your mind is intelligent, not a sign of failure.
/dl
---------------------------------------------------------------------------------David LachBaseline Type & Graphics816 - 736 Granville Street, Vancouver, BC V6Z 1G3 Canadange-newline">
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Ken Freeman
Ann Arbor, MI USA
Ken Freeman
At 2:47 AM -0700 4/10/10, WillemJ wrote:
I remain interested in the larger discussion of optimum tyre size:
where and under what conditions does the advantage of the wider tyre
tail off to become a disadvantage?
That is indeed the big question. Of course, it depends on the road surface. I don't think anybody knows exactly. Mr. Vroomen says that 25 mm is the optimum for most roads, but of course, 25 mm also is the maximum size that fits the bikes he sells.
The Grand Bois Cypres is available with the same casing and same tread thickness in 25.5, 28.5 and 31 mm (actual widths). We tested both the 28.5 and 31 mm, and the results were indistinguishable. However, the test runs weren't back to back, so there is more potential for noise. We hope to do a back-to-back test eventually, so we can see whether the performance really tails off already at 28 - 30 mm.
Similarly, wheel size: While it's intuitive that larger wheels roll better over bumps (see the Co-Motion quote somebody else posted), our results indicate that on average backroads, it isn't a factor. We tested Grand Bois 31 - 622 mm (700C) tires back to back with 32 - 584 mm (650B) tires, and the speeds were indistinguishable. If there is a speed difference, it's small compared to the other factors. I suspect that many 26" tandems run commuter tires that roll slowly, and so they can't keep up with 700C tandems on racing tires...
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com
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Veronica Tunucci
"For me, the main point is that I can enjoy the other advantages of wider
tires - comfort, safety, better cornering - without a decrease in speed.
That, to me, is reason enough to choose wider tires."
Much of our cycling choices are based on individual preferences, it's really
hard to come up with overall conclusions for the greater cycling population.
But on your safety note, I've heard that riding thinner tires is much safer
in the rain, is that not true?
Veronica
Donald Perley
what size tires are generally used for pro time trial stages, where
choosing "right" by a couple miles per hour means real money?
Thinking real roads here, not velodrome or cobbles.
Veronica Tunucci
a 23mm & 25mm tire is similar to the difference between table salt & sea
salt; negligible. :-)
Veronica
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Donald Perley
Sent: Sunday, April 11, 2010 9:59 AM
To: Veronica Tunucci
Cc: Jan Heine; randon
Subject: Re: [Randon] Re: Latest tire rolling resistance data from Al
Morrison
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DrCodfish
"... I have a question. I'm currently have a set of wheels with Mavic
open pro rims.What I would like to know is how wide of tire can I put
on these rims. Would a set of 32mm tires work?"
One data point here: I have been riding Mavic OP Ceramic rims since
about 2004 I think. In that time my tire preference has drifted 'up'
in terms of diameter. I'm on my third set of Rivendel Jack Browns
which Grant P says measure pretty close to 33mm IIRC. I inflate
usually ride them at about 70 psi. Prior to that I rode mostly with
Conti Gatro Skins, 25 and 28mm. So far no problems but the tires do
look 'big' on those rims and for a while I wondered if I was skating
out on the edge of the thin ice. I don't think about it much anymore.
Yr pal, Dr C
George Swain
Bois "Cypres" 30mm on my Mavic Open Pro rims. Both work beautifully.
George
On Apr 9, 8:47 pm, David Lach <dl...@baseline-graphics.com> wrote:
> Hi fellow randonneurs:
>
> I think it would be good for people to concentrate on what is right,
> and in what circumstances, not who is right.
>
> Comments about when people began or stopped thinking a certain way
> just deter people from appropriately modifying their views based on
> the available evidence.
>
> Circumstances differ. People have to apply evidence to their
> circumstances. Changing your mind is intelligent, not a sign of failure.
>
> /dl
>
> On Apr 9, 2010, at 5:35 PM, Bill Gobie wrote:
>
>
>
>
>
> > preston I'd say you're the one who should put the beer down, or get
> > one, or do whatever it takes to chill yourself out.
>
> > This attack on Jan is uncalled for and thankfully unusual on this
> > list.
>
> > Bill Gobie
>
> > On Apr 9, 2010, at 4:56 PM, prestonjb wrote:
>
> >> jan u are full o beer or personal self promotion or something sick..
>
> >> in the paragraph @@@@@@@@directly above this one@@@@@@@@@ sheldon
> >> specifically says that high pressures removes the advantages of the
> >> pneumatic tire specifically "traction" which in what i can see is the
> >> other major player in an equation of your @@real world@@ measurements
> >> as ive seen cited...
>
> >> so his statement below @@@is@@@@ correct and is not wrong even in
> >> this
> >> discussion as long as @@@@you @@@@ include @@@@his entire @@@
> >> statment and not @@@your@@@ selective editing of what sheldon
> >> said!!!!
>
> >> gesh man.... set aside... i got a lot better things to do than watch
> >> ur politics!
>
> >>> "Rolling resistance does decrease theoretically with any increase in
> >>> pressure." and "An overinflated tire will have slightly less rolling
> >>> resistance."
>
> >>> We've learned a lot since Sheldon wrote this, and I am glad that
> >>> Zinn
> >>> was among the first to realize this.
>
> >>> Jan Heine
> >>> Edits.com
>
> > --
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> ------------------------------------------------------------------------
Old5ten
At 10:08 PM -0700 4/9/10, Old5ten wrote:
dead link for Vroomen
At least this evening, the link was active. It's at Scroll down to "Wheels and tyres: Fatter is the way to go"
note the link in your original post:
I don't know of much scientific research that is published online...
It is one thing to make a group such as randon aware of research that one is conducting, even if it is downright lame and ludicrous that the results can't be published electronically!
I can't speak for other fields, but most peer reviewed research in the life sciences is available online (Medline, etc.). Detailed abstracts are usually free, the entire paper may require a subscription.
Bicycle Quarterly is financed by subscribers, which allows us a) to be independent of advertisers and b) to spend significant money on our testing. For example, for the double-blind test of frame stiffness, we had three identical bikes custom-built. Even at a reduced rate (thanks to the builder Jeff Lyon, the tubing maker True Temper, the lug maker Henry James, etc.), the tests cost more than $ 4000, not counting the time our team spent on this. I work full-time on Bicycle Quarterly, plus there is a part-time employee. All this wouldn't be possible without subscribers who pay for it. Making the content online free of charge would be nice, but in effect, it would mean that Bicycle Quarterly wouldn't exist at all. We could try to get advertisers, but then we'd be beholden to them, not our readers. And I am not sure our advertisers would care about a lot of the things we do, like the "The History of Randonneuring" article in the last issue.
Our samples page
http://www.vintagebicyclepress.com/samples.html
has several technical articles that allow you to evaluate our methods and style. From that, you should be able to figure out whether you want to read the rest. We also offer a money-back guarantee in case you don't like the magazine. You only pay for the first issue that you received already. Your total outlay would be $ 7.50. (So far, we have refunded the money 6 times in 8+ years...)
Elmar Stefke
Old5ten
The Summer 2010 issue will compare a carbon and an aluminum racing bike.
Hopefully the carbon bike will be a made in Taiwan, mass produced Specialized S-Works Roubaix SL!
Elmar Stefke (running for cover)
Kole Kantner
With all this talk of one tire being "faster" than another I am curious
what the actual increase in speed is for a specific power input. For
example, how much faster was the 31mm Grand Bois than the 37mm Pasela
and at what speed or power input? This is important to me because I
want to know if it is a worthy area to focus my resources. If the
change is 20mph to 21mph at a 200W input that may only be useful to a
racer looking for every last bit of speed. For some a 5% change is
significant. For me I am more interested in long term equipment cost
and hence I always take into account the difference in cost for each
tire as well as associated costs such as switching to a different frame
or wheel system. I understand that for lower total miles ridden cost is
not as much of an issue. Obviously I am not totally disinterested in
performance differences. I just include cost as one of the performance
parameters.
In my case I am using 700c tires and generally would be curious if there
are dramatic speed differences between budget 23mm models and probably
faster much more expensive models like the Continental GP4000. I
realize this is not the area that Bicycle Quarterly tests focus on, but
if I could change my average speed from 15mph to 20mph by switching
systems I probably would jump on it. If on the other hand switching
from cheap 23mm tires to 31mm Grand Bois only allowed me to change from
15mph to 16mph at a specific power that is only interesting in a
tangential sense to me. Tire rolling resistance is relatively smaller
than wind resistance at some speeds and climbing weight for other
situations.
--Kole--
On 4/7/2010 9:57 PM, Jan Heine wrote:
> At 8:32 PM -0700 4/7/10, J.T. Conklin wrote:
>
>> I think *this* is why it would be useful for a larger selection of
>> wider tires to be represented in the DB. Not for comparing narrow
>> vs. wide, but for comparing different wide tires. eg. Rivendell Jack
>> Browns vs. Grand Bois Cypres vs. Marathon Supremes vs. Vittoria
>> Randonneurs vs. ...
>
> We tested the Rivendell Maxy-Fasty and Nifty-Swifty (basically the
> 650B versions of the Jack Browns). They were among the slowest tires
> we tested. We tested the Schwalbe Marathon Racers (700C x 30 mm), and
> they were among the faster all-round production tires, not far behind
> the Grand Bois Cypres. The Grand Bois was on par with the better
> racing tires, such as the Michelin Pro2 Race. Faster were only
> handmade racing tires, like the Challenge Triathlons and the Vittoria
> Open CX Corsa, as well as the venerable and long-obsolete 28 mm-wide
> Clement Campionato del Mondo tubulars.
>
> We've tried to test all performance tires that are of interest to
> randonneurs. The Vittoria Randonneurs are so heavy and thick that it's
> hard to imagine their being fast. If Vittoria really wanted to do a
> high-performance tire for randonneurs, they'd start with something
> like their CX model...
>
> We hope to do more tire testing, but you need very good conditions
> (absolutely no wind, very constant temperature) to get data that
> reduces the noise.
>
> The coefficient of rolling resistance (CRR) is not a very meaningful
> value, if it is tested on a steel drum. If reflects only the internal
> losses due to internal tire deformation. Much more important are the
> suspension losses due to the vibrations of the bike, and you can
> measure those only with a rider on board, because most of that
> vibration energy is absorbed in the rider's body.
Rob Hawks
among those almost certainly to get my own body weight under control.
That said, if I could figuratively snap my fingers and gain (using
your example of going from 15 to 16mph) 25 minutes per 100 miles by
doing nothing else, I'd jump at that. An increase from 15 to 20mph
just seems to be expecting a lot.
rob hawks
richmond, ca
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Kole Kantner
Thanks for mentioning the time of a reference distance like 100miles or
200km since that is a detail easily comprehended by most. I feel that
tire rolling resistance differences will not add up to 25 minutes in 100
miles, but I might be all wrong on that. Saying certain tires are
"faster" than others does not help me any more than saying that an aero
rim is faster than a squarer rim. I know that the relative drag from a
rim is of no consequence compared to my body drag for the riding I do so
I have no interest in aero rims. Tire rolling resistance is not so
clear to me, though.
If my goal is to reduce the time of a brevet it would be useful to be
able to list the relative importance of the factors I have control
over. It would also be useful to quantify the cost in dollars or other
units as applicable. For example, reducing time spent in controls is
one of the easiest ways to reduce a brevet time and it might even reduce
total dollar cost, but it might have other consequences associated with
it. For many, reducing total brevet time is not important, but reducing
saddle time is, and hence increased speed is still desirable.
--Kole--
Rob Hawks
increase *might* be in the 2% range. Going from 15 to 16mph is a lot
bigger than a 2% increase, and may be the reason why I'd jump at the
chance to improve from 15 to 16mph.
One thing that strikes me as very possible is that the longer the
ride, the bigger the payoff when finding tires that are faster, but
also offer improvements in comfort. I have a lot of bikes, but only
two that I ride on brevets and double centuries. For my main brevet
bike, I've made two big changes. The first was going to a custom frame
built specifically for me. I also switched from Continental Ultra 2000
tires in a labeled 25mm size to Grand Bois 28 x 700 tires. I also made
a somewhat similar tire change on my other bike, which I use primarily
for supported double centuries. I went from the same Continental Ultra
2000 tires to Grand Bois 26mm tires.
The difference observed is far more pronounced on the brevet bike, but
a large part of the improvement could be the custom frame and part is
the change in tires. I do notice an improvement on the double century
bike as well.
Here are the changes I've noticed. For Brevets, in 2009 almost all of
the rides I rode over the same course were done in lower times. The
much bigger improvement however was in how I felt after the ride, both
that evening and the next day. Regardless of which bike I rode in
2009, I always felt less beat up, less battered, and much more eager
to get back on the bike.
It is extremely difficult to quantify that post ride feeling, and
there may be some un-thought of 3rd factor that accounted for it. It
is next to impossible to put a dollar figure on feeling so much better
after a ride, but I'd be willing to bet it was well worth spending
more for better tires. Those Ultra 2000s did not have a supple casing,
not compared to the Grand Bois.
rob hawks
richmond, ca
Veronica Tunucci
assuming my question of going from 23 to 25 mm tires would be less than 1%,
and that is insignificant to me and questionable if it would really be 1%.
If you are seriously interested in reducing saddle time, I would seriously
question why you're doing brevets.
Veronica
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Rob Hawks
I understand your reluctance to switch to a wider tire simply because
the speeds don't increase significantly, but would you do it if at the
end of the same length ride you felt much better, less worn out, less
beat up by rough roads and all at no cost to speed? I would, and am
happy I did. I must sheepishly admit that until I made the change in
tires, I really didn't know such a payoff was possible. I won't deny
that I like to do a brevet faster than I have in the past. My goals
for brevets, in order, are these:
a) finish.
b) finish feeling good (not sore, have an appetite)
c) finish faster than the last time I finished the same route.
I try never to have goal C risk achieving goals A and B.
rob
prestonjb
ive run 35mm on 19mm w no probs though the specs are against that..
Veronica Tunucci
Would I receive this extra comfort changing from 23 to 25mm tires?
Veronica
Steve Palincsar
> I believe Jan's 2% response was going from 20mm to 25mm tires, therefore I'm
> assuming my question of going from 23 to 25 mm tires would be less than 1%,
> and that is insignificant to me and questionable if it would really be 1%.
The difference between 23 and 25mm tires is anything but "insignificant"
-- it's more along the lines of "Holy Shite, Batman!" At my weight I
can drop tire pressure from around 120 to 90 psi, and that has a
profound affect on ride harshness and "road buzz".
25s are also faster rolling, according to both Jan and the tire
companies.
prestonjb
so i dont even have to say things to attract subscribers...
it appears that the 23mm on a typical racing geometry eill produce the
best results on good roads. this includes handling and time savings
per distance.
as an allrounder a slightly larger tire such as a 25mm does better
when rougher roads are encountered.
larger tires that 28mm are typically to handle the extremes and should
be mounted if there are known or expected conditions of rutted roads
or bad pavement for extended stretches. unfortunately 28mm and larger
are not supported by most 'off the rack' bikes...
i run the range of tires and gearing depending on road/weather/load
and grade... so my bike may have 23mm up to 35mm and rear gears
ranging from 12x23 to 14x32 (with the 14x32 being bowl shaped so that
it has many more low gears that the traditional mountain cluster)
i guess i could try to write up a more detailed composition of when
where and how i choose the bile/wheel/tire/gear per ride/conditions...
but then perhaps ... hmm... maybe its just easier to bike :)
prestonjb
desert then u use a 23.. when u are riding along the beach the use
the 25 ;)
prestonjb
>
> Most of the wide tires' safety advantage comes from the fact that
> they don't fit inside most cracks in the road. With 41 mm wide tires,
i'd be careful there least u could be sued...
if they are raised or wet the are still super dangerous and my biggest
beef with Portland Or...
Steve Palincsar
> Rob,
>
> Thanks for mentioning the time of a reference distance like 100miles or
> 200km since that is a detail easily comprehended by most. I feel that
> tire rolling resistance differences will not add up to 25 minutes in 100
> miles, but I might be all wrong on that.
"Randonneuring Basics, Part 3 How to Make Your Bike Faster," BQ Vol 5 No
1 p. 42-45. According to Jan's calculations, for a 70W rider, PBP time
on the fastest tire in his tests was 82 hrs 23 min, vs 97 hours 56
minutes for the slowest tire.
> Saying certain tires are
> "faster" than others does not help me any more than saying that an aero
> rim is faster than a squarer rim. I know that the relative drag from a
> rim is of no consequence compared to my body drag for the riding I do so
> I have no interest in aero rims. Tire rolling resistance is not so
> clear to me, though.
>
> If my goal is to reduce the time of a brevet it would be useful to be
> able to list the relative importance of the factors I have control
> over.
Again for a 70W rider, 5 kg weight difference resulted in a 2 hr 47 min
PBP time difference (less for more powerful riders). Aero position made
a 1 hr 4 min difference for the 70W rider.
prestonjb
trying to save...
the time to switch tires for conditions because u are trying to put ur
name to a R60... or is it easier to just have fun and ride albeit a
tad slower ...
sometimes i just toss out the anal or dysfunctional detail drudgery
and toss my leg on the bike just to enjoy the bike... instead if
worrying about the clock..
and with that view... no then it isnt really that important a
difference ;)
prestonjb
Veronica Tunucci
100psi and I'm quite comfortable. I doubt I would notice the comfort
difference between 23mm and 25mm.
Thanks for the perspective.
Veronica
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
prestonjb
Sent: Sunday, April 11, 2010 4:21 PM
To: randon
Subject: [Randon] Re: How significant is tire rolling resistance compared to
other factors?
--
Veronica Tunucci
speed or do they have the same effect?
Veronica
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Steve Palincsar
Sent: Sunday, April 11, 2010 4:19 PM
To: Kole Kantner
Cc: Rob Hawks; randon
Subject: Re: [Randon] How significant is tire rolling resistance compared to
other factors?
Greg Merritt
> I doubt I would notice the comfort
> difference between 23mm and 25mm.
I find 28's more comfortable than 25's. Same model tire, same bike.
-Greg
Steve Palincsar
> Is there a difference in reducing body weight vs. bike weight to increase
> speed or do they have the same effect?
Weight is weight. There's just a lot more of it on me to lose than
there is on the bike!
Some feel "rotating weight" is a big deal; others say it makes no
difference. Either way doesn't matter, considering the scale. I lost
20 lb last year. Ain't no way you're going to lose 20 lb off your
bike's weight.
prestonjb
i was riding 2.1inch tires today on gravel w 50psi... i enjoy a bit
stiffer springer ride though a bit less traction...
was holding a 19mph pace on a 10mile stretch...
prestonjb
side of the road ;)
On Apr 11, 8:00 pm, Jan Heine <hein...@earthlink.net> wrote:
> At 4:29 PM -0700 4/11/10, Veronica Tunucci wrote:
>
> >I'm a just enjoy the ride cyclist. I currently inflate my 23mm tires to
> >100psi and I'm quite comfortable. I doubt I would notice the comfort
> >difference between 23mm and 25mm.
>
> Think about it in terms of air volume... When you look at the cross
> sections, you'll see the difference:
>
> 23 mm tire: 415 mm2 cross section
> 25 mm tire: 490 mm2 cross section
>
> So you get about 18% more air in your tires when you go from 23 to 25
> mm. I do believe you will notice the difference. If you decrease your
> pressure accordingly, you will be more comfortable, and either faster
> or as fast as before. (If you keep the pressure at 100 psi, the
> comfort difference will be small.)
>
> To add the tires I have been riding lately into the mix:
>
> 31 mm tire: 755 mm2 cross section
> 41 mm tire: 1320 mm2 cross section
>
> That means that the 41 mm tire contains almost 3 times as much air as
> the 23 mm tire.
>
> Make sure you compare tires with the same casing. If you go from a 23
> mm hand-made racing tire - say a Vittoria Open CX Corsa - to a
> stiffer 25 mm tire - say a Continental Ultra-Gatorskin - you may well
> end up less comfortable and slower... To complicate things, some tire
> makers change their casing design as the tires get wider.
prestonjb
and/or more co2 of one is the type to carry gas...
On Apr 11, 8:00 pm, Jan Heine <hein...@earthlink.net> wrote:
> At 4:29 PM -0700 4/11/10, Veronica Tunucci wrote:
>
> >I'm a just enjoy the ride cyclist. I currently inflate my 23mm tires to
> >100psi and I'm quite comfortable. I doubt I would notice the comfort
> >difference between 23mm and 25mm.
>
> Think about it in terms of air volume... When you look at the cross
> sections, you'll see the difference:
>
> 23 mm tire: 415 mm2 cross section
> 25 mm tire: 490 mm2 cross section
>
> So you get about 18% more air in your tires when you go from 23 to 25
> mm. I do believe you will notice the difference. If you decrease your
> pressure accordingly, you will be more comfortable, and either faster
> or as fast as before. (If you keep the pressure at 100 psi, the
> comfort difference will be small.)
>
> To add the tires I have been riding lately into the mix:
>
> 31 mm tire: 755 mm2 cross section
> 41 mm tire: 1320 mm2 cross section
>
> That means that the 41 mm tire contains almost 3 times as much air as
> the 23 mm tire.
>
> Make sure you compare tires with the same casing. If you go from a 23
> mm hand-made racing tire - say a Vittoria Open CX Corsa - to a
> stiffer 25 mm tire - say a Continental Ultra-Gatorskin - you may well
> end up less comfortable and slower... To complicate things, some tire
> makers change their casing design as the tires get wider.
>
Kole Kantner
I have no interest in reducing saddle time, and actually quite the
opposite. However, I am interested in getting as many miles as possible
and there are only so many hours in a year so the faster I go the more
miles I get. Some people I have talked to do seem to have an interest
in reducing saddle time which is the only reason I mentioned that. I
think those mentioning comfort as a goal on the bike have the right
idea, although there are many ways to obtain improved comfort. For me,
riding more seems to improve comfort to a large extent. I do notice
that my Davidson steel tandem feels like an easy chair compared to the
usual early 90's Cannondale frames I use. I'm not sure it is more
comfortable. I just feel the road bumps less.
--Kole--
Old5ten
I doubt I would notice the comfort
difference between 23mm and 25mm.
You might want to give it a try! Based on the ongoing 'virtues of wider tires discussion,' I purchased a pair of Michelin 'Speedium' 700x25 tires (19.93 at REI) and actually rode one on the rear wheel (at 95psi) yesterday on the 'Sweet Terrible One' (pretty darn wet on Skaags). It is by far the least sore I've been in the roughly ten or so times I've done this ride, so from a pure comfort perspective I would say that it is a better ride. There is certainly the weight factor, since the Speedium weighs roughly 70-110 gms more than what I'd normally ride. No idea if it was faster or slower in terms of rolling resistance. To give you a better understanding of what a normal STO ride at 700x23/105-110psi is like: large, dark purple discoloration in the sit bone area, sensitive to pressure and touch. Yesterday: smaller, light red discoloration, with NO pressure/touch sensitivity. Obviously I ran at a lower psi yesterday, but I've run 95psi with 700x23 Michelin Pro2s and Schwalbe Ultremo Rs and not had that type of comfort.
It might be worth a try. I'm an eternal skeptic, but was pleasantly surprised.
Elmar
Kole Kantner
Thanks for the details on the possible magnitude of the difference
between tires. That probably explains why I find flats and downhills so
much more challenging than climbing. I generally don't use tires that
cost more than $10 except for temporary use on special rides. Even then
I probably don't have especially fast tires. Now that I have a power
meter to try I should test out some different tires, although getting
meaningful results will require long duration tests over identical
courses with similar riding conditions.
--Kole--
Jan Heine wrote:
> At 2:54 PM -0700 4/11/10, Kole Kantner wrote:
>
>>>> With all this talk of one tire being "faster" than another I am
>>>> curious what
>>>> the actual increase in speed is for a specific power input.
>
> In our roll-down tests, the slowest and fastest tires were more than
> 20% apart. So for the same power, you might go 14 mph with one, and 16
> mph with another.
>
> If you look at our tests with a power meter, we only tested three
> tires for our suspension loss tests. To ride at 31 km/h on our very
> smooth control surface, the Bontrager Hardcase required 232 Watts, the
> Grand Bois 209 Watts (both tires 25 mm). That is a difference in power
> output of about 10% for the same speed.
>
> This is for a single rider. If you ride in a group, the faster tires
> will give you a greater advantage, as the air resistance is reduced
> when you draft, but tire resistance is constant.
>
> In fact, the biggest difference I noticed when switching to faster
> tires after our initial tire tests was that I got more of a rest in a
> paceline. Before, I'd take my pull, but then had to work hard while
> drafting, instead of getting a rest. This was long before Grand Bois
> tires were available, I used Michelin Pro2 Race and Deda Tre Giro
> d'Italia tires then.
>
> At 3:20 PM -0700 4/11/10, Veronica Tunucci wrote:
>
>> If you are seriously interested in reducing saddle time, I would
>> seriously
>> question why you're doing brevets.
>
> I think Veronica hits the nail on the head. Sure, choose your
> equipment wisely, but don't fret over the last 0.5%. If you are
> concerned about time, you can gain more by keeping your stops short.
> And there is more to randonneuring than speed.
>
> I set up my bike so that I like it, and so that it makes my brevets
> more enjoyable. Fast tires usually are more comfortable, too, and
> hold the road better, so they fit my goals on multiple fronts. A lower
> handlebar position would give me great speed gains, but it would make
> the brevets less enjoyable. So I am actually raising the bars a bit on
> my next bike.
>
> And finally, a disclaimer: Grand Bois tires have been brought into
> this discussion. My company, Vintage Bicycle Press, is the North
> American distributor for these tires. This means I have a small, but
> real commercial interest in this discussion.
Kole Kantner
which both can lead to a stronger rider. Buying lighter equipment
lacks those advantages.
--Kole--
Veronica Tunucci
$19.93! What a bargain, that’s about a third of what I pay for a tire. That’s extra motivation to give the tire a try and my son works at REI, an added bargain.
Maybe you should try a new seat or a bent?
Veronica
From: Old5ten
[mailto:old5...@gmail.com]
Sent: Sunday, April 11, 2010 6:29 PM
To: Veronica Tunucci
Ben Kraft
It's worth noting the 'Speedium' are rather low end tires. I don't know of any scientific tests of their rolling resistance, but the ones I've used felt noticeably slower than my normal tires in the same size.
One way to experiment with the feel of larger tires is to lower the inflation pressure of your current tires and ride rough but consistent roads so you don't get pinch flats. It isn't exactly the same, but I find the effect similar.
For example,
today I rode my "race" bike with 23 mm Conti GP4000's @65 psi on several fast dirt descents. I normally prefer 25's, but these felt very good. Not quite as nice as the GB 30's at 55 psi, but an ok option if you weigh little enough not to worrry about pinch flats (i'm 155, but I don't care much about these rims), and you get the tires for free.
-Ben
--
Bill Gobie
On Apr 11, 2010, at 3:20 PM, Veronica Tunucci wrote:
> If you are seriously interested in reducing saddle time, I would
> seriously
> question why you're doing brevets.
Lighter, faster, farther, tho in my case I can only conjecture this as
the inverse of my experience. The longer you're on the course the more
supplies you need to carry. Sometimes carrying adequate water is a
challenge if you're slow. You have to carry more clothes to deal with
changing weather. On a 600 a slow rider might not get adequate sleep.
You have less time to overcome problems like nav errors, mechanicals,
medical problems, and food issues. And the slower you are, the likely
there will be anyone behind you who might catch up and help you
through tough spots.
Bill Gobie
Bill Gobie
On Apr 11, 2010, at 4:29 PM, Veronica Tunucci wrote:
> I'm a just enjoy the ride cyclist. I currently inflate my 23mm
> tires to
> 100psi and I'm quite comfortable. I doubt I would notice the comfort
> difference between 23mm and 25mm.
Going by Berto's chart, republished by Bicycle Quarterly and available
here [1], for the weight you mentioned previously and 23 mm tires 100
psi should be about right for the rear but you might find 65-70 psi
more comfortable in your front tire.
Bill Gobie
[1] http://sooper-genius.blogspot.com/2007/06/optimum-tire-pressure-35mm-tires.html
Ingle, Bruce
> For me, the main point is that I can enjoy the other
> advantages of wider tires - comfort, safety, better
> cornering - without a decrease in speed. That, to me,
> is reason enough to choose wider tires.
A more practical consideration is the unpredictability of construction
locations and timing on randonneuring routes, including PBP. It would
be advisable to use a tire at least wide enough to allow you to safely
cycle in pea stone and/or sand alongside heavy traffic for a couple of
miles, because you could very easily be hoofing it otherwise. 3 miles
of riding 12 MPH instead of walking 4 MPH saves half an hour.
- Bruce
Charles Coldwell
>
> With all this talk of one tire being "faster" than another I am curious what
> how much faster was the 31mm Grand Bois than the 37mm Pasela and at what
> speed or power input?
Let's suppose you can go 2% faster on the Grand Bois than the Pasela.
I'm making up that number, but I needed something. Then instead of
averaging 16 MPH, you average 16.32, which saves you 18 minutes on a
400K. That's about the time required to fix one flat tire.
I believe JH mentioned that he had three flats on his Grand Bois
during PBP; that's about one every 400K.
So the important question in my mine is, do faster tires which flat
more often improve your speed enough to make up for the time lost to
repairs?
--
Charles M. Coldwell, W1CMC
"Turn on, log in, tune out"
Winchester, Massachusetts, New England (FN42kk)
GPG ID: 852E052F
GPG FPR: 77E5 2B51 4907 F08A 7E92 DE80 AFA9 9A8F 852E 052F
Jerry Zornes
Sent via BlackBerry by AT&T
-----Original Message-----
From: Charles Coldwell <cold...@gmail.com>
Date: Mon, 12 Apr 2010 09:15:30
To: Kole Kantner<kkan...@gmail.com>
Cc: Jan Heine<hei...@earthlink.net>; randon<ran...@googlegroups.com>
Subject: Re: [Randon] How significant is tire rolling resistance compared to
other factors?
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Steve Palincsar
> On Sun, Apr 11, 2010 at 5:02 PM, Kole Kantner <kkan...@gmail.com> wrote:
> >
> > With all this talk of one tire being "faster" than another I am curious what
> > the actual increase in speed is for a specific power input. For example,
> > how much faster was the 31mm Grand Bois than the 37mm Pasela and at what
> > speed or power input?
>
> Let's suppose you can go 2% faster on the Grand Bois than the Pasela.
> I'm making up that number, but I needed something. Then instead of
> averaging 16 MPH, you average 16.32, which saves you 18 minutes on a
> 400K. That's about the time required to fix one flat tire.
>
> I believe JH mentioned that he had three flats on his Grand Bois
> during PBP; that's about one every 400K.
>
> So the important question in my mine is, do faster tires which flat
> more often improve your speed enough to make up for the time lost to
> repairs?
That's definitely true. 2% difference is very close, though. Comparing
the fastest to the slowest tire gives you a much more dramatic spread:
as much as 3 mph difference.
Stephen Whiteman
Leaving aside traction and safety (important, but not immediately relevant) and comfort (which seems, at least up to some point +/- 30c, to track rolling resistance), weight is an important issue (in response to another message, I don't know anyone who believes there isn't a difference between rotating and static mass). Does weight impact rolling resistance directly? Or do the things that make tires heavier also, coincidentally, make them less efficient rollers? Or is there no correlation? These questions may have been answered in Jan's and other's studies, I'm just not clear.
(This also ties into my view of the frame weight question recently discussed: yes, I can lose weight, and yes, that's the best way to make the total package lighter, but on any given day, I weigh what I weigh. While I don't think that sacrificing equipment weight at the expense of durability is a good trade-off, I also don't understand the common Riv School view that weight just doesn't matter -- a heavy bike is a heavy bike, whatever my waist size. Why push more than I have to, so long as my gear meets other needs (safety, comfort, reliability, etc.)?)
An alternative take on the flats vs time question (which again may reflect my comparative inexperience): what are the emotional or other practical effects of lots of flats? I ran Conti 4 Seasons in my Last Chance and had no flats in 1200K. By day 4, I was tired enough that I might have found a flat quite discouraging. On day 3, I was with a fast moving group that was really helping me, both in effort and morale. The group was large enough, and my contribution was small enough, that they might not have waited for me if I'd flatted (I don't blame them for this) -- I would have lost a lot more time and emotional energy soloing in than any tires might have cost me.
Stephen
--
In the brave new world, all scholarly questions will be resolved by crowd sourcing. (Michael Lee)
> Date: Mon, 12 Apr 2010 09:15:30 -0400
> Subject: Re: [Randon] How significant is tire rolling resistance compared to other factors?
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Donald Perley
> Or do the things that make tires heavier also, coincidentally, make them
> less efficient rollers? Or is there no correlation?
The correlation probably isn't 100%, but in general heavier tires are
thicker and stiffer, so it takes more energy to flex them from round
to the shape of the contact patch and back every time around.
David Lafferty
expectancies and reliability for tires. Some tires may cost more up
front, but last much longer and flat less (therefore saving money on
tubes and patches). Here are a few tires I've used till they wore
out:
Rear:
IRC Tandem 700x30 - 11,000 miles with about 8 flats
Continental Ultra Gatorskin 700x28 - 10,000 miles with about 7 flats
Continental Ultra Gatorskin 700x28 - 8,000 miles with about 5 flats
Continental GP4000 700x23 - 5,000 miles
Continental Force 700x23 - 3,000 miles
Innova Tundra Wolf (studded) 700x35 - 800 miles with no flats (studs
wore out)
Nashbar Folding Road Tire 700x26 - 200 miles with 3 flats (plenty of
life left, but now it's only allowed on the trainer)
Front:
Continental Ultra Gatorskin 700x25 - 10,000 miles with no flats
Continental Grand Prix 700x25 - 8,000 miles with about 1 flat
Continental GP4000 700x23 - 6,000 miles with about 1 flat
Continental Attack 700x22 - 4,000 miles
Innova Tundra Wolf (studded) 700x35 - 800 miles with no flats (studs
wore out)
I've noticed that tires tend the wear better and last longer if
they're inflated reasonably (like the Berto tire chart recommends)
than if they're inflated to the maximum printed on the sidewall.
Your mileage may vary.
Cheers,
David
On Apr 11, 5:02 pm, Kole Kantner <kkant...@gmail.com> wrote:
> Jan,
>
> With all this talk of one tire being "faster" than another I am curious
> what the actual increase in speed is for a specific power input. For
> example, how much faster was the 31mm Grand Bois than the 37mm Pasela
> and at what speed or power input? This is important to me because I
Tom Rosenbauer
inflated to 100psi (mounted on Mavic Open Pro CD rims). I can usually get
at least 4,000 miles of use out of tire, however, I don't risk wringing out
every last bit of tread before replacement.
When replacing a tire, I will rotate my current front tire to the rear
(which will already have serveral months of use) and put the fresh tire on
the front where it belongs, IMHO. (If you wait for the front tread to wear
down before replacing it, you risk having a sidewall failure which will most
certainly ruin your day if if happens on a 50 MPH descent).
I can often go an entire season without a flat -- if I can get past the
first couple of weeks with a brand new tire. Like a fine wine, tires seem
to improve with age by becoming more flat resistant... it seems to me that
older tires are less likely to hold on to bits of glass that eventually work
their way through the casing.
As an engineer, I am very reluctant to mess with something that is working.
However, based on the recent discussion, I might give the 25mm a try some
day.
Regards,
-Tom Rosenbauer
Eastern PA RBA
----- Original Message -----
From: "David Lafferty" <davi...@gmail.com>
To Kole's point, maybe this group can contribute to a list of life
expectancies and reliability for tires....
Rob Hawks
If you get 4000 miles out of a rear tire, I'd find that remarkable. I
once got 5000 out of a rear tire, but I did try to wring every last
mile out of that tire. I get flats with regular frequency, but
generally not on longer rides. Mostly it is on my commute that I get
flats.
rob hawks
richmond, ca
Tom Rosenbauer
Just to clarify my mileage on a particular tire ... part of the mileage will
be while it's mounted on the front, when it is first installed on the bike.
The remaining mileage will be on the rear, as part of my replacement scheme
I had outlined.
-Tom Rosenbauer
----- Original Message -----
From: "Rob Hawks" <rob....@gmail.com>
If you get 4000 miles out of a rear tire, I'd find that remarkable. ....
On Mon, Apr 12, 2010 at 8:49 AM, Tom Rosenbauer <trose...@rcn.com> wrote:
>
> .... When replacing a tire, I will rotate my current front tire to the
rear
> (which will already have serveral months of use) and put the fresh tire on
> the front where it belongs, IMHO. (If you wait for the front tread to wear
> down before replacing it, you risk having a sidewall failure which will
most
> certainly ruin your day if if happens on a 50 MPH descent).....
>
>