Question about ride quality of aluminium with carbon stays
Roy
to cut down on the stiffness of the material? Can you compare the ride
quality to anything else out there? As a reference I ride a LOOK,
Bianchi Boron XL and Bianchi MegaTi. How would the ride quality
compare to those?
AEDv8sc
Sorni
news:d3d948f6.03090...@posting.google.com...
I doubt that there's a pat answer to your question.
I recently bought a Klein Team Q-carbon (aluminum w/carbon seat stays), and
find the ride quite smooth compared to the other bikes I test-rode (steel,
al and ti). Someone else might totally disagree, however.
Bill "it's about the bike...fit?" S.
Gearóid Ó Laoi/Garry Lee
do not know what kind of frame they are riding, they can't tell. It's been
tested.
H. Guy
it's been tested? you know, i've always suspected that "ride qualities"
might be mostly psychological (though i HATED my 1986 vintage c-dale
and LOVE my 1997 vintage kestrel) but didn't know that it's been tested.
can you please give a pointer to or info about the tests? how were
they conducted? how'd they disguise the construction of the frames?
what types were compared (alu, steel, alu/cf, ti, etc)?
tia for your reply!!
hg
Chalo
The stiffness of carbon depends on the amount, density, and direction
of the embedded fibers, as well as the shape of the structure in which
they are laid. The stiffness of aluminum depends upon the diameters,
wall thicknesses, and lengths of the tubes in the structure.
Therefore, the effect that such frame construction will have is
uncertain and dependent upon specific traits of the frame in question.
Mixed frame materials as a rule are intended to enhance marketability
and perceived value but not any tangible element of performance. A
mixed-material frame will almost certainly cost more than a frame made
of its cheaper component, while failing to deliver any detectably
different ride characteristics.
Chalo Colina
Mark Hickey
The most famous blind test was done by 'Bicycle Guide', when they had
seven (IIRC) bikes built with every tube set available from Columbus
(IIRC). Even though the writers of the day (and even that magazine)
were waxing poetic about the drastic differences between two adjacent
sets of pipes, suddenly they couldn't identify which was which - at
ALL! In fact, the cheapest tubes got the highest overall rating by
the testers. It was really pretty comical - but pretty much what
you'd expect given the physics of a bike frame.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Gearóid Ó Laoi/Garry Lee
and got "experts" to describe the ride and guess what they were riding. They
hadn't a clue. I read the magazine but it was more than 10 years ago and I
can't remember what mag it was, but it was British.
H. Guy
wait, were they all steel, or a mix of different materials?
Qui si parla Campagnolo
A carbon stays, particularly one supported at both ends(seat stay only) , does
nothin' to change the ride of this or any other material. It is mostly
marketing and painted as a 'performance' advantage.
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Qui si parla Campagnolo
and perceived value but not any tangible element of performance. A
mixed-material frame will almost certainly cost more than a frame made
of its cheaper component, while failing to deliver any detectably
Very well said...
John Everett
Comparing the ride quality of one bike to another has more to do with
tires, tire pressures, and saddle than tube materials. Want to change
ride quality? Change one of those.
jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3
G. Huang
>
> Comparing the ride quality of one bike to another has more to do with
> tires, tire pressures, and saddle than tube materials. Want to change
> ride quality? Change one of those.
In the 80's, when I switched from a aluminum tennis racket to a graphite
one, I could definitely tell the difference in vibration-damping
characteristics. Many others felt the same way. Was it just imagination?
Was it due to different grip material of the graphite racket? Or, what
applies to rackets dosen't apply to forks?
I have not owned anything other than all steel road bikes but am
thinking of getting a new Al bike with a carbon fork, thus my interest
in hearing the opinions.
GH
Gearóid Ó Laoi/Garry Lee
That's the difference.
Roy
Each of the above bikes has the same saddle and wheel set so it is
easy to judge them. IMO the LOOK rides feels more comfortable in 50
plus mile rides than the Mega Ti especially long flat rides. The
MegaTi climbs better than both especally with agressive climbing. The
Boron is very comfortable good for general ridding. Is is my
imagination, NO. They ride different. You have to consider angles and
the rest of the construction of the bike as well. You can make a
carbon bike ride hard by thickness of tube walls and angles. Example
Trek OCLV compared to LOOK. or You can make an aluminium fram ride
more comfortable - Cannondale compared to a Vitus 992. There are alot
of variables.
I agree that carbon mixed the aluminium is a marketing thing. There
are a few bikes that have combined chain and seat stays with good
results e.g. Bianchi Ti-Carbon, 7 Cycles to name few. It would seam
that approach would make more differce than just carbon stays.
DiabloScott
> You don't have a tyre between your racket and the ball. That's the
> difference.
Why don't I see anybody saying that carbon forks on aluminum/steel/ti
bikes are just marketing gimmicks? Seems most folks agree that carbon
forks do handle better than steel or aluminum ones and absorb road shock
better, why is it otherwise for rear triangles?
--
Check out my bike blog!
http://diabloscott.blogspot.com
>--------------------------<
Posted via cyclingforums.com
http://www.cyclingforums.com
jobst....@stanfordalumni.org
> Why don't I see anybody saying that carbon forks on
> aluminum/steel/ti bikes are just marketing gimmicks? Seems most
> folks agree that carbon forks do handle better than steel or
> aluminum ones and absorb road shock better, why is it otherwise for
> rear triangles?
The only thing they lean on is weight savings, the ride quality is
only alluded to or implied as a result of a few grams less weight.
Unfortunately the UCI did not step in early enough to stop this idiocy
of charging more and more for less and less... by a couple of grams
for a few thousand dollars. There is a minimum weight rule now but
it's too low mainly to not ban products already on the market that
have been developed at great expense.
Smoothness of ride arises from tires, not from frame materials. The
so called "rear triangle" is in fact a tetrahedron whose dimensions
change by no more than a few thousandths of an inch. A tetrahedron (a
six element solid figure) is stressed only in tension and compression
in the bicycle. Therefore there is no perceptible difference in road
shock through the saddle to the rider.
Head tube rake of the frame is designed to load forks primarily in
compression from road irregularities, other than from braking. Rake
angle tries to match the size of the most common road irregularities
encountered a front wheel of conventional diameter so that it fork
sustains primarily axial compression.
Frames, other than ones with suspension elements, do not absorb shock.
Ride comfort can only be changes by wheelbase change, the longer the
chainstays, the more comfortable the ride. Other than that, the
pneumatic tire does the rest.
Jobst Brandt
jobst....@stanfordalumni.org
David L. Johnson
> Why don't I see anybody saying that carbon forks on aluminum/steel/ti
> bikes are just marketing gimmicks? Seems most folks agree that carbon
> forks do handle better than steel or aluminum ones and absorb road shock
> better,
Your premise is wrong. People do say that carbon forks do not "handle
better" than steel or aluminum, and they do not absorb road shock better.
The differences, if any, in shock absorbtion between various forks is an
order of magnitude less than the shock absorbtion of the tire. So, you
could not tell if there were an advantage, since the advantage is less
than that last puff of air you put in your tire.
Thre is a distinction between carbon forks, and carbon pieces in a frame,
from this point of view, though. Carbon forks are now competitive in
price with aluminum or steel. The big difference is weight, and even
there carbon and aluminum are competititve. But carbon stays on a frame
seem to double the price, for no benefit.
--
David L. Johnson
__o | A mathematician is a machine for turning coffee into theorems.
_`\(,_ | -- Paul Erdos
(_)/ (_) |
jim beam
> forks do handle better than steel or aluminum ones and absorb road shock
> better, why is it otherwise for rear triangles?
it ain't. carbon rears, just like seat posts & forks, /do/ take a lot
of the sting out of the road. they're not stiffer overall, or sloppier
overall, but they /do/ take a lot of the road vibe out.
truthfully, i was skeptical until i rode some of this stuff myself. you
have two very dissimilar materials in these composites. the modulus of
graphite fiber is very high but the modulus of the resin that holds it
together is very low. in unstressed steel reinforced concrete and
pre-stressed reinforced concrete, the difference in performance of the
former is that it is initially more "flexible" until the steel starts
picking up more of the load. pre-stressed concrete is "stiffer" but has
a lower failure stress because the pre-load detracts from the total
available strength of the steel.
similarly, fibers embedded in resin, for current fabrication methods at
least, are not pre-stressed and this means that for a small portion of
the load, you're merely straining plastic, not high modulus fiber.
great for small amplitude road vibration damping. the result of large
strains is of course dependant on the fiber, hence these frames remain
stiff overall.
it's also interesting to note that one of the fatigue modes for
composites has been the "loosening" of the fiber in the matrix - the
fiber is free to slide. this gives a mushy feel because you're
basically just riding resin.
jb
DiabloScott
[B]Diablo Scott writes:
> Why don't I see anybody saying that carbon forks on aluminum/steel/ti bikes are just marketing
> gimmicks? Seems most folks agree that carbon forks do handle better than steel or aluminum ones
> and absorb road shock better, why is it otherwise for rear triangles?
The only thing they lean on is weight savings, the ride quality is only alluded to or implied as a
result of a few grams less weight. Unfortunately the UCI did not step in early enough to stop this
idiocy of charging more and more for less and less... by a couple of grams for a few thousand
dollars. There is a minimum weight rule now but it's too low mainly to not ban products already on
the market that have been developed at great expense.
Smoothness of ride arises from tires, not from frame materials. The so called "rear triangle" is in
fact a tetrahedron whose dimensions change by no more than a few thousandths of an inch. A
tetrahedron (a six element solid figure) is stressed only in tension and compression in the bicycle.
Therefore there is no perceptible difference in road shock through the saddle to the rider.
Head tube rake of the frame is designed to load forks primarily in compression from road
irregularities, other than from braking. Rake angle tries to match the size of the most common road
irregularities encountered a front wheel of conventional diameter so that it fork sustains primarily
axial compression.
Frames, other than ones with suspension elements, do not absorb shock. Ride comfort can only be
changes by wheelbase change, the longer the chainstays, the more comfortable the ride. Other than
that, the pneumatic tire does the rest.
Jobst Brandt [email]jobst....@stanfordalumni.org[/email] [/B][/QUOTE]
Interesting info Jobst; although I count eight members in the rear “triangle” including the brake bridge (bottom tube and seat tube members are very small of course).
Rather than “road shock” I should have written “vibration dampening” which is what the reviews and marketing usually attribute to the carbon fiber – so we’re talking about high-frequency buzz like you’d get on a chip seal road surface rather than large bumps. Are you saying vibration dampening is a non-issue? Why would the buzz attenuation be any different in the front than the back?
And reviewers DO write about the better handling characteristics of carbon forks, although mostly they site the stiffness rather than any material property. Is this just nonsense?
So – do you think carbon forks are marketing gimmicks or not? If so, why aren’t you as vocal against carbon forks as you are against carbon stays?
[QUOTE][i]Originally posted by David L. Johnson wrote:
> Your premise is wrong. People do say that carbon forks do not
> "handle better" than steel or aluminum, and they do not absorb road
> shock better.
> The differences, if any, in shock absorption between various forks is an
> order of magnitude less than the shock absorption of the tire. So, you
> could not tell if there were an advantage, since the advantage is less
> than that last puff of air you put in your tire.
> Thre is a distinction between carbon forks, and carbon pieces in a
> frame, from this point of view, though. Carbon forks are now competitive
> in price with aluminum or steel. The big difference is weight, and even
> there carbon and aluminum are competititve. But carbon stays on a frame
> seem to double the price, for no benefit.
> --
A quick check through my catalogues finds one steel fork for $30 and
one aluminum fork for $40 while the carbon forks range from $90 to
$500. On the Eddy Merckx frames (Leader and Race) the carbon rear stays
increase the price by about $300. So it seems that carbon rears
increase the price of a frame by about the same amount as a carbon fork
does; huge generalization of course but much less than your “double the
price” figure.
So David - do you think carbon forks are marketing gimmicks? If you
can’t tell the difference in ride quality between aluminum and carbon
forks, and the weight is about the same, why aren’t you as vocal against
carbon forks as you are against carbon stays?
I’m not trying to be argumentative here, it just seems that most of
the things people are writing against carbon stays can also be written
about carbon forks. I’m curious why no one has done so. I’m open to
the idea that carbon forks really are marketing gimmicks but it seems
they have near universal acceptance while carbon stays have near
universal contempt.
jobst....@stanfordalumni.org
> Interesting info Jobst; although I count eight members in the rear
> "triangle" including the brake bridge (bottom tube and seat
> tube members are very small of course).
Look up tetrahedron in you math book and you'll find that it has four
surfaces and six edges. The brake bridge plays no role in load
carrying. It is there to mount the brake and adds nothing to the
strength of the figure. The six elements are 2-chainstays,
2-seatstays, seat tube and rear axle.
> Rather than "road shock" I should have written "vibration dampening"
> which is what the reviews and marketing usually attribute to the
> carbon fiber; so we’re talking about high-frequency buzz like you’d
> get on a chip seal road surface rather than large bumps. Are you
> saying vibration dampening is a non-issue? Why would the buzz
> attenuation be any different in the front than the back?
It may not be obvious but the seat and chainstays are thin tubes
because they carry only compressive and tensile forces, unlike the
large tubes of the frame that carry torsion and bending. That's why
the "rear triangle" is made of such slender tubes.
> And reviewers DO write about the better handling characteristics of
> carbon forks, although mostly they site the stiffness rather than
> any material property. Is this just nonsense?
That's the point. Reviewers are fashion critics and rarely have any
idea about what they write. It needs to sound good but contain no
data or proofs of reality. The unwitting public is so used to this
kind of spin doctoring that they don't even notice it anymore and when
asked repeat what the article alluded to but never said.
> So – do you think carbon forks are marketing gimmicks or not? If
> so, why aren’t you as vocal against carbon forks as you are against
> carbon stays?
Absolutely. In fact, until they came on the market we never heard of
a fork disintegrating while riding along. This is a relatively common
occurrence with carbon forks. You won't see me descending the Stelvio
pass with a carbon fork.
Having a fork fail at any one of these hairpin turns is easily fatal.
> > Originally posted by David L. Johnson wrote:
> > Your premise is wrong. People do say that carbon forks do not
> > "handle better" than steel or aluminum, and they do not absorb
> > road shock better.
> > The differences, if any, in shock absorption between various
> > forks is an order of magnitude less than the shock absorption of
> > the tire. So, you could not tell if there were an advantage,
> > since the advantage is less than that last puff of air you put
> > in your tire. There is a distinction between carbon forks, and
> > carbon pieces in a frame, from this point of view,
> > though. Carbon forks are now competitive in price with aluminum
> > or steel. The big difference is weight, and even there carbon
> > and aluminum are competitive. But carbon stays on a frame seem
> > to double the price, for no benefit. --
So how about learning how to write to wreck.bike in the net etiquette?
Your character set and inclusions are hard to decipher. If you haven't
noticed, the protocol is to add a ">" before anything cited, thus
">>>" means from three postings ago with two subsequent responses.
> A quick check through my catalogues finds one steel fork for $30 and
> one aluminum fork for $40 while the carbon forks range from $90 to
> $500. On the Eddy Merckx frames (Leader and Race) the carbon rear
> stays increase the price by about $300. So it seems that carbon
> rears increase the price of a frame by about the same amount as a
> carbon fork does; huge generalization of course but much less than
> your "double the price" figure.
And you think this is a good indicator of anything useful? Why do
"stylish" bicycle glasses with less than a dollar's manufacturing
cost, sell for $60+. For the same reason. They're IN! Gotta have
it.
> So David - do you think carbon forks are marketing gimmicks? If you
> can’t tell the difference in ride quality between aluminum and
> carbon forks, and the weight is about the same, why aren’t you as
> vocal against carbon forks as you are against carbon stays?
This also doesn't work well. If you want a response from David, put
the request in a response to his posting. However, I'll offer that
they are entirely marketing gimmicks and hazardous ones at that.
> I’m not trying to be argumentative here, it just seems that most of
> the things people are writing against carbon stays can also be
> written about carbon forks. I’m curious why no one has done so.
> I’m open to the idea that carbon forks really are marketing gimmicks
> but it seems they have near universal acceptance while carbon stays
> have near universal contempt.
The idea of carbon came to make a bicycle lighter. In response steel
frames have become lighter and are still more reliable than "plastic?"
Now that we have a minimum weight, they have to claim something else.
Your vibration damping is pretty far fetched. There may be an
acoustic difference. You may have noticed that light weight tires
make a rushing sound whose frequency is able to resonate in a steel
frame. Other materials are so dead that they don't do that.
Jobst Brandt
jobst....@stanfordalumni.org
David L. Johnson
>
> And reviewers DO write about the better handling characteristics of carbon
> forks, although mostly they site the stiffness rather than any material
> property. Is this just nonsense?
Reviewers write all sorts of nonsense. Think about it. Have you ever
read a negative review of _any_ high-priced bike component in Bicycling?
Can they _all_ be worth the money?
> A quick check through my catalogues finds one steel fork for $30 and one
> aluminum fork for $40 while the carbon forks range from $90 to $500.
I can find steel forks for $90 (Sheldon has one), and probably more are
around. If you buy it as part of the bike, the difference in price will be very
small.
On
> the Eddy Merckx frames (Leader and Race) the carbon rear stays increase
> the price by about $300.
But there are others that are only offerred with the carbon stays, and
those tend to be the priciest.
So it seems that carbon rears increase the price
> of a frame by about the same amount as a carbon fork does; huge
> generalization of course but much less than your “double the price”
> figure.
Perhaps my generalization was a bit high, but $30 to $90 is $60 for your
prices to go from steel to carbon fork, versus $300 for the rear stays.
>
> So David - do you think carbon forks are marketing gimmicks?
Like I said, they are lighter than steel, and available at roughly the
same price. I have a carbon fork -- which I got from a swap meet for $25.
Works fine. Is it magic? Will it make the ride smooth? No. The $400
forks are those that are all-carbon, which I wouldn't ride on a bet.
> If you can’t
> tell the difference in ride quality between aluminum and carbon forks, and
> the weight is about the same, why aren’t you as vocal against carbon
> forks as you are against carbon stays?
I'm not vocal against either; I just don't think they are worth a lot of
extra money.
>
> I’m not trying to be argumentative here,
Sure you are
> it just seems that most of the
> things people are writing against carbon stays can also be written about
> carbon forks. I’m curious why no one has done so.
You keep saying that as if it were true.
> I’m open to the idea
> that carbon forks really are marketing gimmicks but it seems they have
> near universal acceptance while carbon stays have near universal
contempt.
Your comparisons -- even with your price quotes -- are faulty. Forks are
easily-replacable components. Carbon forks are available from every shop
and catalogue company for a price that is competitive with what a decent
fork of any other material would cost. The difference in price is small.
For instance, Nashbar sells an aluminum fork for $80, and a carbon, on
sale, for $50. OK, the carbon is their own brand; they have an Easton
for $90.
On the other hand, carbon stays will save a lot less weight than carbon
forks (vs steel, certainly, and likely aluminum as well), for a lot more
money. Any other advantage they claim is marketing hype. They add a
large premium to the price of the frame.
--
David L. Johnson
__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |
DiabloScott
>So how about learning how to write to wreck.bike in the net >etiquette?
>Your character set and inclusions are hard to decipher. If you haven't
>noticed, the >protocol is to add a ">" before anything cited, thus
>">>>" means from three postings ago with >two subsequent responses.
Yeah, I apologize. Unfortunately this "Cycling Forums" gateway to UseNet
adds hidden formatting to my posts that makes me look like a tyro
instead of the netiquette master that I am. I try to anticipate what it
will do and provide counter-formatting but am on occasion unsuccessful.
>Look up tetrahedron in you math book and you'll find that it has >four
>surfaces and six edges. The brake bridge plays no role in load
>carrying. It is there to mount >the brake and adds nothing to the
>strength of the figure. The six elements are 2-chainstays,
>2->seatstays, seat tube and rear axle.
Yeah, I deserve that one too, thought I was being clever. You win.
>> So – do you think carbon forks are marketing gimmicks or not? If so,
>> why aren’t you as vocal against carbon forks as you are against
>> carbon stays?
>Absolutely. In fact, until they came on the market we never >heard of a
>fork disintegrating while riding along. This is a relatively common
>occurrence with carbon >forks. You won't see me descending the Stelvio
>pass with a carbon fork.
At last! A direct answer (at least half of an answer). Thank you. I
am glad to see that there is consistency in the evaluation of the
two elements, that was my concern which apparently got lost in my
awkward netoric.
So just for the record, according to JB - carbon stays are pure hype and
carbon forks are hype and dangerous. (great photo btw)
Maurizio
> idea about what they write. It needs to sound good but contain no
> data or proofs of reality.
True.
> Absolutely. In fact, until they came on the market we never heard of
> a fork disintegrating while riding along. This is a relatively common
> occurrence with carbon forks.
I guess you can easily provide some data or proofs or reality on what you've
just written.
Maurizio
Per Elmsäter
Well it could also mean that those selfproclaimed experts really didn't know
very much about bicycles.
--
Perre
You have to be smarter than a robot to reply.
Jay Hill
couldn't tell the difference), but I've never heard of one that
compared al, carbon, steel, & ti.
Qui si parla Campagnolo
bikes are just marketing gimmicks? Seems most folks agree that carbon
forks do handle better than steel or aluminum ones and absorb road shock
Most rear carbon is just a seat stay, supported at both ends, which makes any
ride changes unlikely. And a well made steel fork will handle just as well as a
carbon one.
David Damerell
>it ain't. carbon rears, just like seat posts & forks, /do/ take a lot
>of the sting out of the road. they're not stiffer overall, or sloppier
>overall, but they /do/ take a lot of the road vibe out.
Except in blind tests, of course.
--
David Damerell <dame...@chiark.greenend.org.uk> flcl?
David Mackintosh
> How do the aluminium frams ride that have carbon stays? Do they help
> to cut down on the stiffness of the material? Can you compare the ride
> quality to anything else out there? As a reference I ride a LOOK,
> Bianchi Boron XL and Bianchi MegaTi. How would the ride quality
> compare to those?
>
I think most people who have ridden similar bikes with both aluminum
and carbon seat stays would agree that there is a noticeable
difference, although as a mechanical engineer, I can't explain why it
would be more than just barely perceptable.
I've recently just switched all my parts back and forth between an '01
Klein Quantum Race (all Al) and an '03.5 Orbea Altec 2+ with carbon
seatstays. The only parts that weren't identical were the front der.,
and the seatpost (both Thomson Al, but different diameters). Same
wheels and seat, bars and stem. The geometry is pretty similar. The
Orbea has a slightly slacker seat tube, and shorter chainstays. My
position was quite similar, but my saddle was farther back over the
rear wheel on the Orbea, which should have made the ride harsher on
that bike, if anything. The Orbea was noticeably much smoother, with
a more comfortable ride over long distances. I had to check to make
sure the tire pressure was the same. After a couple of weeks I
switched all the parts back to the Klein frame. Initially it felt
like I was riding on a flat rear tire, with the rim bottoming out on
small bumps. There are other differences between the two frames. The
Klein main tubes are larger diameter and round or oval. The Orbea
tubes are generally smaller and "shaped" (diamond down tube and top
tube). A better experiment would be to ride two identically-equipped
Kleins, with and without the carbon stays. I would be very suprised
if anyone who did this on chip-seal or other moderately rough pavement
said that they couldn't tell the difference.
I've also tried two different forks on the Klein: the stock Icon Air
Rail (carbon blades, Al steerer, 43mm rake), and an Alpha Q Pro Z (for
Zinn, with extra thick carbon steerer, 44mm rake). The Pro Z is
noticeably stiffer and significantly improved the handling during
technical descents.
David Mackintosh
BaCardi
Carbon stays will never make up for aluminum's deficiencies.
--
Terry Morse
> Carbon stays will never make up for aluminum's deficiencies.
You knew that you would be asked to explain that comment. What, in
your opinion, are aluminum's deficiencies?
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
David L. Johnson
> I think most people who have ridden similar bikes with both aluminum and
> carbon seat stays would agree that there is a noticeable difference,
Sure. Most of those people will have just shelled out big bucks for a new
bike. They have to justify the expense somehow.
> although as a mechanical engineer, I can't explain why it would be more
> than just barely perceptable.
How well would you expect to perceive something lost in the noise? Since
the damping of the tire is well beyond any claims of the damping of any
frame material, how can it be felt?
--
David L. Johnson
__o | You will say Christ saith this and the apostles say this; but
_`\(,_ | what canst thou say? -- George Fox.
(_)/ (_) |
Cary Paugh
can't give you any of the techincal stuff but I can tell you there is
a very definate difference between both steel with and w/o carbon stay
and aluminum with and w/o. I ended up buying an aluminum frame with
carbon stays and am very pleased and I was coming off an old high end
steel frame that is in theory softer riding than aluminium. I will
also tell you I tested a relatively high end Cannondale with there
"wishbone" stays and it vibrated the **** out of me.
Peter Cole
news:d3f7e4e3.03090...@posting.google.com...
> roybi...@aol.com (Roy) wrote in message
news:<d3d948f6.03090...@posting.google.com>...
> > How do the aluminium frams ride that have carbon stays? Do they help
> > to cut down on the stiffness of the material? Can you compare the ride
> > quality to anything else out there? As a reference I ride a LOOK,
> > Bianchi Boron XL and Bianchi MegaTi. How would the ride quality
> > compare to those?
> >
> > AEDv8sc
>
> I think most people who have ridden similar bikes with both aluminum
> and carbon seat stays would agree that there is a noticeable
> difference, although as a mechanical engineer, I can't explain why it
> would be more than just barely perceptable.
Perhaps a psychologist could.
Werehatrack
may have said:
>Jobst Brandt wrote:
>
>>Absolutely. In fact, until they came on the market we never >heard of a
>>fork disintegrating while riding along. This is a relatively common
>>occurrence with carbon >forks. You won't see me descending the Stelvio
>>pass with a carbon fork.
>
>At last! A direct answer (at least half of an answer). Thank you. I
>am glad to see that there is consistency in the evaluation of the
>two elements, that was my concern which apparently got lost in my
>awkward netoric.
>
>So just for the record, according to JB - carbon stays are pure hype and
>carbon forks are hype and dangerous. (great photo btw)
Trust Jobst to have the lowdown on a lot of overhyped marketech.
Chalo's observations were particularly cogent as well.
I have noticed that high-end bikes seem to be getting the same kind of
buzzword-driven redesign treatment that has afflicted other products;
if the currently fashionable material or technique is X, then everyone
rushes to get out a product made using X *even if it's shoddy*, simply
because there will be demand for that product. It happened with
radial tires thirty years ago, it happened with front-wheel-drive cars
a little later, it has happened to various other products, and it even
happens with food. ("Blackened egglant" springs to mind...)
--
My email address is antispammed;
pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
jobst....@stanfordalumni.org
> True.
Well, let me restrict that a bit:
In fact, until they came on the market -I- never heard of a fork
disintegrating while riding along. I have heard of from riders who
witnessed them and from the bicycle shop mechanics that carbon forks
had failed without striking an object. One of these occurred shortly
after a high speed descent, in the flat run-out after the hill.
It could be that these people are making these stories up and that it
is a smear campaign. I believe them.
Jobst Brandt
jobst....@stanfordalumni.org
Richard Ney
> Maurizio Soppa writes:
>
>>> That's the point. Reviewers are fashion critics and rarely have any
>>> idea about what they write. It needs to sound good but contain no
>>> data or proofs of reality.
>
>> True.
>
>>> Absolutely. In fact, until they came on the market we never heard
>>> of a fork disintegrating while riding along. This is a relatively
>>> common occurrence with carbon forks.
>
>> I guess you can easily provide some data or proofs or reality on
>> what you've just written.
>
> Well, let me restrict that a bit:
>
> In fact, until they came on the market -I- never heard of a fork
> disintegrating while riding along. I have heard of from riders who
> witnessed them and from the bicycle shop mechanics that carbon forks
> had failed without striking an object. One of these occurred shortly
> after a high speed descent, in the flat run-out after the hill.
Are these disintegrating forks all carbon, or are they carbon bladed
with steel steerers?
Chalo
>
> carbon rears, just like seat posts & forks, /do/ take a lot
> of the sting out of the road. they're not stiffer overall, or sloppier
> overall, but they /do/ take a lot of the road vibe out.
>
> truthfully, i was skeptical until i rode some of this stuff myself. you
> have two very dissimilar materials in these composites. the modulus of
> graphite fiber is very high but the modulus of the resin that holds it
> together is very low. in unstressed steel reinforced concrete and
> pre-stressed reinforced concrete, the difference in performance of the
> former is that it is initially more "flexible" until the steel starts
> picking up more of the load.
Your analysis betrays some misunderstanding about the properties of
CFRP. Yes, there are two or more materials involved. Yes, those
separate materials have different properties. But that does not mean
that the composite is not subject to the same principles as any other
structure.
There is no significant internal "pre-stress" in a metal frame; it
begins to deflect starting at zero load, just like composite. The
modulus of any common frame material is for all relevant purposes
linear within the range of normal operational stresses. You suggest
that CFRP can be both a low-modulus and a high-modulus material
depending on stress level. Theoretically that might be so, but only
within a range of stresses so low that they do not apply to a
lightweight frame or other structural bike part that is in the process
of being ridden.
The situation where that property (variable modulus) might be tangible
is in the case of fully reversing stress cycles, like a fork vibrating
fore-to-aft. I will assume that the vibrations characterized by some
riders as "harsh", "unforgiving", or "tiring" are not fore-to-aft, but
vertical. This is because on a bike, the magnitude of vertical
momentary accelerations dwarfs any in the other two axes (until you
collide with something).
Vertical stress on a fork {or a frame) is not reversing, at least not
often enough to be called "vibe" or "buzz". Furthermore, in handling
carbon forks I have found that they ring when struck just about as
readily as metal ones do, and in comparable fundamental frequencies.
That makes me wonder how significant any effect such as you describe
could possibly be.
Note that the largest deflection by far in any rigid fork is in the
steerer. Yet carbon forks with steel or aluminum steerers have the
same reputation for mysteriously smooth ride qualities as those with
carbon steerers. Hmm....
Carbon forks do sound different, which I believe may be what causes
you to ascribe special shock-attenuating characteristics to them.
A given carbon frame or other load-bearing part is either stiffer than
a given metal one, or it is less stiff, but it is not somehow
magically both according to the rider's wishes.
Chalo Colina
Chris Zacho The Wheelman
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
jobst....@stanfordalumni.org
>>>> Absolutely. In fact, until they came on the market we never
>>>> heard of a fork disintegrating while riding along. This is a
>>>> relatively common occurrence with carbon forks.
>>> I guess you can easily provide some data or proofs or reality on
>>> what you've just written.
>> Well, let me restrict that a bit:
>> In fact, until they came on the market -I- never heard of a fork
>> disintegrating while riding along. I have heard of from riders who
>> witnessed them and from the bicycle shop mechanics that carbon
>> forks had failed without striking an object. One of these occurred
>> shortly after a high speed descent, in the flat run-out after the
>> hill.
> Are these disintegrating forks all carbon, or are they carbon bladed
> with steel steerers?
I didn't bother to ask since I am not about to have anything to do
with such forks. Does it make any difference? As far as I know, the
people reported splintered carbon fibers.
Jobst Brandt
jobst....@stanfordalumni.org
G Huang
> The differences, if any, in shock absorbtion between various forks is an
> order of magnitude less than the shock absorbtion of the tire. So, you
> could not tell if there were an advantage, since the advantage is less
> than that last puff of air you put in your tire.
But does that necessarily diminish the difference between different
forks? Let me throw in some simple-minded, hypothetical numbers to
explain my point. Assuming the shock energy is E, let's say the tire has
a transfer coefficient of 0.04 (meaning it lets 4% of E go through), and
the Al fork and carbon fork have the transfer coefficients of 0.8 and
0.4, respectively (both at least an order of magnitude higher than the
tire). Without considering the other components, shouldn't the rider
receive 0.032*E of the shock energy due to the Al fork and only 0.016*E
due to the carbon fork?
So, it seems that regardless of how much the tire contributes to the
shock absorption the ratio between the shock energy through the Al fork
and the shock energy through the carbon fork remains the same. In other
words, if I can feel the difference without the tire, I should feel the
same difference with the tire.
GH
A Muzi
> >> That's the point. Reviewers are fashion critics and rarely have any
> >> idea about what they write. It needs to sound good but contain no
> >> data or proofs of reality.
>
> > True.
>
> >> Absolutely. In fact, until they came on the market we never heard
> >> of a fork disintegrating while riding along. This is a relatively
> >> common occurrence with carbon forks.
>
> > I guess you can easily provide some data or proofs or reality on
> > what you've just written.
<jobst....@stanfordalumni.org> wrote in message
news:WeM5b.18370$dk4.5...@typhoon.sonic.net...
> Well, let me restrict that a bit:
>
> In fact, until they came on the market -I- never heard of a fork
> disintegrating while riding along. I have heard of from riders who
> witnessed them and from the bicycle shop mechanics that carbon forks
> had failed without striking an object. One of these occurred shortly
> after a high speed descent, in the flat run-out after the hill.
>
> It could be that these people are making these stories up and that it
> is a smear campaign. I believe them.
Yes that happens. We've all seen them.
However I was trying out for "cassandra" when cheap no-name carbon forks
became suddenly fashionable two years ago, predicting mayhem.
I have to say I was wrong. I am impressed that there are not _more_
failures, given how shoddily they are made and the huge numbers of them out
there.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
Mike Jacoubowsky
> disintegrating while riding along. I have heard of from riders who
> witnessed them and from the bicycle shop mechanics that carbon forks
> had failed without striking an object. One of these occurred shortly
> after a high speed descent, in the flat run-out after the hill.
>
> It could be that these people are making these stories up and that it
> is a smear campaign. I believe them.
Believe what you wish. But the truth is that we see *no* greater incidence
of mysterious, JRA-type (just riding along) failure in carbon than we saw in
steel. For that matter, of the many thousands of bikes with carbon forks
that we've sold (and that number is not inflated), I have yet to see an
honest JRA failure of a carbon fork. I *do* see far, far fewer forks being
replaced due to damage from accidents. Are customers running into fewer
things these days? I seriously doubt it.
Carbon forks seem considerably less likely to fail in a crash than steel
forks, which would frequently bend back. One could argue that a carbon fork
won't bend, but instead will simply fail outright, if the impact is
significant enough. Could be true, but the "significant enough" event is
exceedingly rare. My own personal datapoint involves a car that backed out
of a driveway into me. Bent the steel fork column, but the carbon blades
were untouched. Too bad my left front tooth wasn't as strong!
--Mike-- Chain Reaction Bicycles
http://www.ChainReactionBicycles.com
Terry Morse
> Carbon forks seem considerably less likely to fail in a crash than steel
> forks, which would frequently bend back.
But a bent-back steel fork is not failed, the blades are simply bent
back and can be straightened. I've done it many times.
There are people in the local cycling club who have had carbon fork
failures while "just riding along", complete with medical bills.
David Mackintosh
> On Thu, 04 Sep 2003 07:30:37 +0000, David Mackintosh wrote:
>
> > I think most people who have ridden similar bikes with both aluminum and
> > carbon seat stays would agree that there is a noticeable difference,
>
> Sure. Most of those people will have just shelled out big bucks for a new
> bike. They have to justify the expense somehow.
Possibly. This was the opposite in my case, however. I shelled out
to buy a carbon-stayed frame thinking it would be an improvement over
my all-aluminum one, but found that it wasn't (but for
non-comfort-related reasons) and am now planning to sell it.
> > although as a mechanical engineer, I can't explain why it would be more
> > than just barely perceptable.
>
> How well would you expect to perceive something lost in the noise? Since
> the damping of the tire is well beyond any claims of the damping of any
> frame material, how can it be felt?
Good question. But, rather than putting such high confidence in the
theory (with which I essential agree), I suggest you try a similar
experiment (two frames with all other parts being identical). I was
surprised at the result.
Actually, although the flex in the tire is well beyond what I would
expect in any stay material, I'm not so sure that the damping is
orders of magnitude different (I was using 23mm tires at 105psi). As
I said, I can't explain the reason for the difference in feel, but I
would be very surprised to find that a majority of riders couldn't
immediately tell the difference in ride quality between two aluminum
frames that are otherwise fairly similar, one with and one without
carbon stays.
Try it, and report back!
-David
Mike S.
"G Huang" <gang@removethis_bell-labs.com> wrote in message
news:3F57FB40.8040408@removethis_bell-labs.com...
Good luck trying to convince the "experts" on this one. They've already
made up their minds. ...and without even riding them first!
I'm with you. I had (sold it TT too short) a TET cross frame with a steel
fork, and a pair of bikes with Time carbon forks on them. I could
immediately tell that there was more "buzz" through the front end of the
cross bike using the same wheels on all 3 bikes. I can't really tell a big
difference between the Time fork on my Bontrager, the C3 fork on my S-Works,
and my Ouzo Pro on my track bike. 1. has a steel steerer, 2. has an AL
steerer, and 3. is all carbon.
Seems to me that if there's less road vibration going up your arms adding
fatigue, you'll be able to ride that much longer/faster.
But I'm not an engineer, so I don't know what I'm talking about...
Mike
Mark Hickey
>Mark Hickey wrote:
>> The most famous blind test was done by 'Bicycle Guide', when they had
>> seven (IIRC) bikes built with every tube set available from Columbus
>> (IIRC). Even though the writers of the day (and even that magazine)
>> were waxing poetic about the drastic differences between two adjacent
>> sets of pipes, suddenly they couldn't identify which was which - at
>> ALL! In fact, the cheapest tubes got the highest overall rating by
>> the testers. It was really pretty comical - but pretty much what
>> you'd expect given the physics of a bike frame.
>>
>
>Well it could also mean that those selfproclaimed experts really didn't know
>very much about bicycles.
I'd say MOST self-procaimed experts probably don't know much about
bicycles. Most of them deny that the laws of physics apply to bikes
like they do to other things, for example.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Mike S.
> carbon one.
>
I'll give you that they handle the same (or at least similarly), but they
ride completely differently.
See my post above in this thread.
Mike
Mike S.
> Absolutely. In fact, until they came on the market we never heard of
> a fork disintegrating while riding along. This is a relatively common
> pass with a carbon fork.
>
Impacts, yes, accidents, yes, explode for no apparent reason, no.
You've obviously also forgotten the Columbus Max forks from just a little
while ago: 94-6. I had a shop-mate of mine go through 2 of them in a
season.
This goes back to the question from a few days ago in the "OK hands up"
thread. If you haven't ridden something extensively, what makes you an
expert on that particular piece of equipment? (I'm not bashing Jobst
specifically here, mind you.) I can understand that on general principals
it shouldn't make a big difference, but if you haven't ridden it, how the
hell would you know one way or another? At least the guys writing the
reviews have actually RIDDEN what they're writing about.
If you haven't ridden a '87 Canondale Crit frame how can you understand how
much it hurt? If you haven't ridden discs, how do you know whether they are
a problem or not. I respect people here for what they know about what they
know about. When they start going off on things that they're clueless
about, it bothers me because people listen to what they say and take it as
gospel.
Yes, I know that marketing is hyping the latest thing as the best thing
since sliced bread. No, I don't own a bike with a carbon rear end. No, I
don't feel qualified to make an assessment because I have NO PRACTICAL
EXPERIENCE with them. I am also smart enough to know that I don't know so
generally keep my trap shut.
All right, I'm done bitching. Now for the recommendations: if you're
bashing something GO OUT AND RIDE IT. Ride it for several weeks/months.
Test it against your personal benchmark bike. Keep an open mind when you're
testing it, THEN let us know what you think. What are the plusses, minuses?
At least then we can have an opinion of someone with no reason to try and
sell us something.
Mike
Mike S.
"Mike Jacoubowsky" <mik...@ix.netcom.com> wrote in message
news:U1U5b.9845$3m1....@newssvr27.news.prodigy.com...
riding a steel steerer/carbon straight bladed fork. The crown/steerer
junction was off, but the fork blades were fine. (I don't remember what I
did with it, I'd send it to someone to do a study)
Mike
Mike S.
> Try it, and report back!
>
> -David
THAT's the key.
Mike
Maurizio
> In fact, until they came on the market -I- never heard of a fork
> disintegrating while riding along. I have heard of from riders who
> witnessed them and from the bicycle shop mechanics that carbon forks
> had failed without striking an object. One of these occurred shortly
> after a high speed descent, in the flat run-out after the hill.
>
> It could be that these people are making these stories up and that it
> is a smear campaign. I believe them.
So do I.
But I think it's not a matter of material. Carbon seems to disintegrate
rather to bend or break. Given this, I think I would never trust a 300g fork
in the Stelvio descent. Mine is 550g and I'm pretty confindent it wouldn't
fail.
Some year ago I read an interview to Ernesto Colnago. He told that, after
having introduced the straigh bladed steel fork "Precisa", the amount of
forks I had to replace due to failure decreased a lot. And he was talking
about STEEL forks to replace, not carbon one. How many frames does Ernesto
sell over a year? Say thousands? If I recall correctly, 20 or 30 forks
broke. Could be interesting to have some statistics over carbon, too.
Ciao,
Maurizio
Chalo
> But does that necessarily diminish the difference between different
> forks? Let me throw in some simple-minded, hypothetical numbers to
> explain my point. Assuming the shock energy is E, let's say the tire has
> a transfer coefficient of 0.04 (meaning it lets 4% of E go through), and
> the Al fork and carbon fork have the transfer coefficients of 0.8 and
> 0.4, respectively (both at least an order of magnitude higher than the
> tire). Without considering the other components, shouldn't the rider
> receive 0.032*E of the shock energy due to the Al fork and only 0.016*E
> due to the carbon fork?
What you may be missing is that none of the components of the system
do any significant energy dissipation at all. They act more like
springs, attenuating peak force during compression and then releasing
their stored energy during rebound.
So a better model would be a 50kN/cm spring sitting on top of a 1kN/cm
spring. Press them down, and they both deflect, but the soft spring
will bottom out before there is any noticeable action in the hard
spring. In practice the compliance of the softer spring makes the
harder spring feel basically the same as if it were infinitely stiff.
As long as the soft spring is within its working range, any compliance
of the stiff one will be masked.
For any amount of deflection in the soft spring, there will be 2% as
much in the hard one. Sensing a difference, then, means being able to
distinguish between 50 and 51 by feel. You can't do it with a pack of
dollar bills, and you can't do it with a "smooth riding" composite
fork, frame, or wheel.
There are other cues, like the sound or the amount of lateral
deflection, that may make you believe a composite structure is
"absorbing" or attenuating vertical shocks. But it's not, by any
reasonable definition. The tire, saddle, handlebars and grips, even
the cranks and pedals are capable of doing far more to deflect under
bump forces.
Chalo Colina
Jay Hill
> I
> would be very surprised to find that a majority of riders couldn't
> immediately tell the difference in ride quality between two aluminum
> frames that are otherwise fairly similar, one with and one without
> carbon stays.
>
> Try it, and report back!
I replaced a steel Gios frame with a steel fork with a steel Lemond
frame with a carbon fork. All other components were the same. I
immediately felt the difference in damping from the carbon fork, and
I hadn't been looking for it.
I'd like to see some blind tests done. The people here who are
saying that carbon forks are purely the result of fashion need to
point to a blind or double-blind test proving their assertions. And,
in that test, they should use a wide variety of carbon forks,
including those such as Reynolds' Ouzo, which Reynolds advertised as
being designed specifically to reduce vibration.
Mark Hickey
>I'm with you. I had (sold it TT too short) a TET cross frame with a steel
>fork, and a pair of bikes with Time carbon forks on them. I could
>immediately tell that there was more "buzz" through the front end of the
>cross bike using the same wheels on all 3 bikes.
An honest question - did you expect to feel a smoother ride on the
carbon fork when you rode it?
Peter Cole
news:8LV5b.44436$cj1.8770@fed1read06...
>
> This goes back to the question from a few days ago in the "OK hands up"
> thread. If you haven't ridden something extensively, what makes you an
> expert on that particular piece of equipment? (I'm not bashing Jobst
> specifically here, mind you.)
No, you're bashing science and engineering. The whole purpose of these
disciplines is to create models from which behavior can be accurately
predicted. The bicycle frame doesn't require a very complicated model.
> I can understand that on general principals
> it shouldn't make a big difference, but if you haven't ridden it, how the
> hell would you know one way or another?
The same way you know whether a bridge will fall down or not.
> At least the guys writing the
> reviews have actually RIDDEN what they're writing about.
And, they're selling the products (at least indirectly). Their opinion is, at
best, purely subjective, at worst, commerce-driven.
> I respect people here for what they know about what they
> know about.
I don't think so, you dismiss basic engineering principles explained by those
who have spent a lifetime mastering them, then accuse those engineers of being
arrogant. That's not my idea of respect.
> When they start going off on things that they're clueless
> about, it bothers me because people listen to what they say and take it as
> gospel.
I wouldn't lose any sleep over it, it looks like more people are buying the
hype than the engineering.
> All right, I'm done bitching. Now for the recommendations: if you're
> bashing something GO OUT AND RIDE IT. Ride it for several weeks/months.
> Test it against your personal benchmark bike. Keep an open mind when you're
> testing it, THEN let us know what you think. What are the plusses, minuses?
> At least then we can have an opinion of someone with no reason to try and
> sell us something.
All this would do is give another subjective opinion. I've heard the same
arguments in the steel vs.. aluminum debate. I've ridden both, and detected no
difference, but since that's only another subjective opinion, I wouldn't
expect it to prove anything. I haven't got the time, inclination, or
disposable income to try every bicycle permutation on the market, even if it
would prove anything. I don't need to, that's the whole point of science and
engineering.
Rick Onanian
wrote:
>> difference, although as a mechanical engineer, I can't explain why it
>> would be more than just barely perceptable.
>
> Perhaps a psychologist could.
Good point; I'd add, for people who think they
feel the difference, the issue of whether or not
there really is a difference is not important.
If they [think that they] feel a difference,
who cares if there is a scientifically measurable
difference or not? If it makes them happy and
excited about the bike, then they will ride it
more, and it was worth the [money? whatever else
is given up to get something like carbon stays?].
--
Rick Onanian
Rick Onanian
wrote:
> if the currently fashionable material or technique is X, then everyone
> rushes to get out a product made using X *even if it's shoddy*, simply
> because there will be demand for that product. It happened with
> radial tires thirty years ago, it happened with front-wheel-drive cars
Are you saying that radials or front wheel drive
are shoddy, or just that everybody went out and
got them without thinking for themselves?
I'd argue that, while I've never driven on bias-ply,
radials have been great to me; and have you ever
driven rear wheel drive on highways with black ice?
Granted, with proper practice, you can avoid getting
stuck with rear wheel drive, and can even avoid
acceleration-related understeer most of the time;
but when you're crusing at a steady speed on the
highway, and the rear suddenly decides to get in
front of you...just because of a patch of invisible
black ice that a front wheel drive would have gone
over straight.
> a little later, it has happened to various other products, and it even
> happens with food. ("Blackened egglant" springs to mind...)
I only eat what I find yummy.
I would not likely try anything that was "blackened",
nor an "egglant", or even an "eggplant" (which is
what I think you meant). Eggs come from dodos,
not plants!!!! <G>
--
Rick Onanian
terry morse
> I replaced a steel Gios frame with a steel fork with a steel Lemond
> frame with a carbon fork. All other components were the same.
Same exact frame geometry, tires, saddle, handlebar tape, fit?
>I immediately felt the difference in damping from the carbon fork,
and
> I hadn't been looking for it.
>
> I'd like to see some blind tests done. The people here who are
> saying that carbon forks are purely the result of fashion need to
> point to a blind or double-blind test proving their assertions.
Blind testing is not necessary when evaluating a mechanical device.
Humans are pretty poor test equipment, actually.
jim beam
> spring. Press them down, and they both deflect, but the soft spring
> will bottom out before there is any noticeable action in the hard
> spring. In practice the compliance of the softer spring makes the
> harder spring feel basically the same as if it were infinitely stiff.
> As long as the soft spring is within its working range, any compliance
> of the stiff one will be masked.
but we're not talking spring steel, we're talking composites. do you
know about hysteresis loops?
jb
Duffy Pratt
"terry morse" <tmo...@spamcop.net> wrote in message
news:1d7ea2f8.03090...@posting.google.com...
> Jay Hill wrote:
> Blind testing is not necessary when evaluating a mechanical device.
> Humans are pretty poor test equipment, actually.
People claim that the different materials feel different in use. The most
direct way to prove, or disprove, that is by doing some blind tests. Of
course, that wouldn't mean much to the true believers.
Just look at the high end audio market. There are tons of people who "hear"
differences between high end audio equipment. Then double blind tests show
that they couldn't hear any difference at all, if they didn't know what
components they were listening to at all. The audiophiles response is that
blind testing is invalid.
Duffy
Peter Cole
news:opru064y...@news.east.cox.net...
> On Thu, 04 Sep 2003 18:52:32 GMT, Peter Cole <peter...@comcast.net>
> wrote:
> >> difference, although as a mechanical engineer, I can't explain why it
> >> would be more than just barely perceptable.
> >
> > Perhaps a psychologist could.
>
> Good point; I'd add, for people who think they
> feel the difference, the issue of whether or not
> there really is a difference is not important.
Fair enough. Safety issues aside, there's only the downside of the effective
designs being displaced by less effective ones. In this case, I doubt that
carbon-stayed bikes will displace all the other models on the market. But,
this *is* rec.bicycles.*tech*, where the topic is technology, not perception.
Mike Jacoubowsky
> back and can be straightened. I've done it many times.
And how many times have people had previously bent-back steel forks that
have later cracked? I've seen a number of them. Further, how many people
have ridden previously-bent, now seriously-weakened steel forks that, while
JRA, ran the front wheel into the downtube, causing a *severe* crash? Again,
I've seen a number over the years.
> There are people in the local cycling club who have had carbon fork
> failures while "just riding along", complete with medical bills.
I'd love to see them. Of the several JRA broken carbon forks that have come
into our shop, we've been able to run back the problem to something
encountered on the road. The most popular trick is to pick up something
from the road that gets caught in the front wheel and locks it up; PG&E is
notorious for leaving nasty metal scraps on the ground from line repairs.
In the real world, there will obviously be an occasional defective product,
but carbon is no different from steel in that regard and, as I've said (a
number of times), steel forks have failed in the past, do fail presently and
will continue to do so in the future. Fork failure is not a feature of the
material, but rather something encountered on the road or defects in
workmanship. If carbon forks were likely to fail, you wouldn't see TDF
riders risking their lives on them; they're putting far more stress than you
or I (particularly sprinters, I would think).
If only I could turn back the clock 20 years, and we could have a discussion
about the dangers of the improperly-designed steel forks out there... (not
that they were actually improperly designed, but I'm sure that's what people
would say as opposed to running the accident backward and discovering what
had actually happened...)
--Mike-- Chain Reaction Bicycles
http://www.ChainReactionBicycles.com
"Terry Morse" <tmo...@spamcop.net> wrote in message
news:tmorse-177533....@news.covad.net...
Fred Clydesdale
tmo...@spamcop.net (terry morse) wrote:
> Jay Hill wrote:
> >
> > I'd like to see some blind tests done. The people here who are
> > saying that carbon forks are purely the result of fashion need to
> > point to a blind or double-blind test proving their assertions.
>
> Blind testing is not necessary when evaluating a mechanical device.
> Humans are pretty poor test equipment, actually.
well, that's why you make it a blind test. just because the numbers
show that the differences will be minimal doesn't mean that they
aren't detectable by some.
i used to give some weight to the assertions of golden-eared
audiophiles, though i couldn't hear the differences they were claiming
existed between various amplifiers. then i read the results of several
carefully-controlled ABX blind tests.
i've seen the same kind of arguments here: one side says "the numbers
claim you can't feel a difference" and the other says "it's *there*!
are you *blind*?" i'd love to see a blind test (if that's possible),
using those who claim to feel a difference as the participants. if
the results fall into statistical noise, then i'm willing to accept
the fact that the differences aren't real. until then, i only know
what my butt and shoulders are communicating to me. (non-verbally,
i'd like to add. i'm not THAT crazy.)
Gary Young
> Believe what you wish. But the truth is that we see *no* greater incidence
> of mysterious, JRA-type (just riding along) failure in carbon than we saw in
> steel. For that matter, of the many thousands of bikes with carbon forks
> that we've sold (and that number is not inflated), I have yet to see an
> honest JRA failure of a carbon fork. I *do* see far, far fewer forks being
> replaced due to damage from accidents. Are customers running into fewer
> things these days? I seriously doubt it.
Is that really a good thing? I thought one of the disadvantages of
carbon fiber is that damage may not be readily apparent. Perhaps the
just-riding-along failures that other people report are really just
the aftermath of collisions that didn't appear to damage the fork.
Mike S.
"Mark Hickey" <ma...@habcycles.com> wrote in message
news:v52hlv8s05gb9ghli...@4ax.com...
> "Mike S." <mikeshaw2@coxDOTnet> wrote:
>
> >I'm with you. I had (sold it TT too short) a TET cross frame with a
steel
> >fork, and a pair of bikes with Time carbon forks on them. I could
> >immediately tell that there was more "buzz" through the front end of the
> >cross bike using the same wheels on all 3 bikes.
>
> An honest question - did you expect to feel a smoother ride on the
> carbon fork when you rode it?
>
Y'know, not really. I'm one of those guys that tends to be skeptical of the
newest, bestest thing that companies are hyping. I try to honestly evaluate
what I've put on the bike, comparing it to what just came off. I've got two
road bikes, so one usually gets the upgrade, the other stays as is for a
while to test said upgrade.
I'd like to try out a carbon rear triangle bike to see whether it does
actually make a difference. I don't want to BUY a carbon rear triangle
bike, just try it out for a month or so. I'd consider it if its proven to
be a better ride.
I don't go jump on whatever bandwagon everyone else is jumping on. When
everyone was upgrading to carbon forks back in the mid-90s, I was still
riding my steel and AL forks. Since they weren't proven to be an upgrade, I
didn't see the need to spend all the $$ to basically be a beta tester. I'm
still waiting to see what kind of durability carbon bars have. A few ounces
on the bike doesn't make up for the extra weight around my middle...
That help?
Mike
Benjamin Weiner
Don't be snide. Composites aren't magic. The appropriate model
is two springs each with some amount of damping - that is, imperfect
springs which absorb energy. Tires certainly behave this way,
one could even estimate the coefficient of restitution by dropping a
wheel and seeing to what percentage of the original height it bounces.
We wouldn't get a useful measurement by doing that to a frame,
composite or no, which tells us something about how much shock
it can absorb right there. Even if the frame had a low coefficient
of restitution (high damping), which I doubt, it can't absorb much
energy compared to the tire, because as a spring it is so much stiffer.
David Damerell
>Blind testing is not necessary when evaluating a mechanical device.
>Humans are pretty poor test equipment, actually.
It would be an effective way to debunk a lot of the supposed difference
that can be allegedly easily felt.
--
David Damerell <dame...@chiark.greenend.org.uk> flcl?
Werehatrack
may have said:
>On Thu, 04 Sep 2003 19:13:31 GMT, Werehatrack <rau...@earthWEEDSlink.net>
>wrote:
>> if the currently fashionable material or technique is X, then everyone
>> rushes to get out a product made using X *even if it's shoddy*, simply
>> because there will be demand for that product. It happened with
>> radial tires thirty years ago, it happened with front-wheel-drive cars
>
>Are you saying that radials or front wheel drive
>are shoddy, or just that everybody went out and
>got them without thinking for themselves?
Many of the late-60s/early-70s US-made radials were shoddy, there's no
question, and yes, people went out and bought radials -- ANY radials
-- precisely because they were alleged to be better, which in the main
they were. Not all were good, though; some very popular and awful
examples soon proved to be on the market, including the infamous
Firestone 500.
It should be noted that European radials had been on the market for a
number of years at that point, but they were limited to a few sizes
and brands, which very few US drivers had ever used. The US tire
producers, however, all jumped on the radial bandwagon once the
advantages were publicized...and many rushed to the marketplace with a
product that wasn't ready because they hadn't really had a chance to
learn what they didn't know yet.
>I'd argue that, while I've never driven on bias-ply,
>radials have been great to me; and have you ever
>driven rear wheel drive on highways with black ice?
Yes, but not often, and not by choice. That's what studs, chains, and
etc., were for. (And you didn't go very far or very fast under those
conditions.)
Bias-ply tires have their place, but when *good* radials are
available, there's no reason to fit a car with *any* bias-ply tires.
If, however, the choice is between good bias ply tires vs. crummy
radials with a strong tendency to sidewall self-destruction without
warning (the first US-made Dunlops had that problem) or which develop
tread separations despite proper loading and inflation (the Firestone
500 did that) or one of the other poorly designed versions (most of
which are long gone from the public's consciousness), then I
would...and did...take the bias ply tires.
>Granted, with proper practice, you can avoid getting
>stuck with rear wheel drive, and can even avoid
>acceleration-related understeer most of the time;
>but when you're crusing at a steady speed on the
>highway, and the rear suddenly decides to get in
>front of you...just because of a patch of invisible
>black ice that a front wheel drive would have gone
>over straight.
True, but when you're driving your front-wheel-drive car down a clear,
open patch of summer highway, and the drive chain in the transmission
snaps (early GM transaxles), or the main planetary shells out (early
Taurus, among others), or the left axle unplugs on a bump because of a
bad engine mount (many Chrysler units), and you later compare notes
with all the folks at work who have had similar incidents which would
not have been likely (or perhaps even possible) in an older design,
you start to wonder what's so great about these front wheel drive
cars. It takes *time* for a design to become mature, and that
maturity is achieved at the expense of warts and bruises accumulated
by the users.
Bleeding-edge tech is almost always *less* reliable than solid,
proven, *old* tech. This does not mean that the new tech will *never*
be better, but it does imply that if reliability is an issue, then
history and not hype should be the primary determinant of the choice
of product to buy.
>> a little later, it has happened to various other products, and it even
>> happens with food. ("Blackened egglant" springs to mind...)
>
>I only eat what I find yummy.
>
>I would not likely try anything that was "blackened",
>nor an "egglant", or even an "eggplant" (which is
>what I think you meant). Eggs come from dodos,
>not plants!!!! <G>
And eggplant (yes, that's what I meant) is only marginally edible
under the best of circumstances, though still infinitely preferable to
okra. (I have not yet seen blackened okra on a menu anywhere, but
since the "blackened x" craze seems to be dying at last, perhaps it
won't happen.)
--
My email address is antispammed;
pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
trent gregory hill
> "Rick Onanian" <spam...@cox.net> wrote in message
> >
> > Good point; I'd add, for people who think they
> > feel the difference, the issue of whether or not
> > there really is a difference is not important.
>
> Fair enough. Safety issues aside, there's only the downside of the effective
> designs being displaced by less effective ones. In this case, I doubt that
> carbon-stayed bikes will displace all the other models on the market. But,
> this *is* rec.bicycles.*tech*, where the topic is technology, not perception.
>
There's the rub. While it may be convenient, for engineering purposes, to
treat the person riding the bike as a black box (who's fairly
uninteresting and unreliable as a test subject) whose only function is to
apply force to the pedals, in practice they and their perceptions are
crucial to understanding both the qualitative and quantitative dimensions
of riding a bike. I'm as skeptical as anyone else here of bike
manufacturer's marketing technobabble, but this sentiment--that you can
discuss bicycle technology in isolation from human factors--is frequently
voiced on this NG, and is frankly incomprehensible.
Trent
Mike DeMicco
news:nbS5b.18555$dk4.5...@typhoon.sonic.net:
>> Are these disintegrating forks all carbon, or are they carbon bladed
>> with steel steerers?
>
> I didn't bother to ask since I am not about to have anything to do
> with such forks. Does it make any difference? As far as I know, the
> people reported splintered carbon fibers.
>
I think it makes a huge difference. Isn't this ancient history? Practically
no one buys a steel bike anymore and most forks are made out of aluminum or
carbon fiber, with the steerer tube being the only part of the fork being
steel. With the large volume of carbon forks being sold today, if there
were a problem with them, it would be common knowledge by now.
Mike Jacoubowsky/Chain Reaction Bicycles
> carbon fiber is that damage may not be readily apparent. Perhaps the
> just-riding-along failures that other people report are really just
> the aftermath of collisions that didn't appear to damage the fork.
I would agree that there is a problem with some materials not readily
showing damage after impact, and further, that the cost of replacing
high-end parts discourages people from doing so when it would be
appropriate. That's one of the reasons I really dislike carbon handlebars;
they're quite vulnerable in a crash, but, due to their cost, people will
rationalize that they're probably OK.
So, from an absolute safety standpoint, the world might be better off if
everything was only made of the least-expensive materials so there was less
financial pain involved in replacing them, removing some of the disincentive
to replacing potentially-damaged goods.
--Mike--
Chain Reaction Bicycles
www.ChainReaction.com
"Gary Young" <garyy...@hotmail.com> wrote in message
news:bfbe6ed3.03090...@posting.google.com...
Chalo
> Chalo wrote:
> > practice the compliance of the softer spring makes the
> > harder spring feel basically the same as if it were infinitely stiff.
> > As long as the soft spring is within its working range, any compliance
> > of the stiff one will be masked.
>
> but we're not talking spring steel, we're talking composites. do you
> know about hysteresis loops?
First of all, hysteresis doesn't really come into it, at least from
sources other than the tire. Carbon forks ring; carbon frames ring.
They are not effective dampers except over a span of kilocycles. You
still get hit back with 99.9%+ of the energy you put in.
Getting back to the spring analogy, can you see that even if there
were a fluid damper combined with the stiffer spring, it would still
feel like a purely rigid body atop the softer spring? Its share of
the total displacement is infinitesimal, and whatever damping it
possesses can only act upon that portion of the whole.
Chalo Colina
David L. Johnson
> David L. Johnson wrote:
>> The differences, if any, in shock absorbtion between various forks is an
>> order of magnitude less than the shock absorbtion of the tire. So, you
>> could not tell if there were an advantage, since the advantage is less
>> than that last puff of air you put in your tire.
>
> But does that necessarily diminish the difference between different forks?
> Let me throw in some simple-minded, hypothetical numbers to explain my
> point. Assuming the shock energy is E, let's say the tire has a transfer
> coefficient of 0.04 (meaning it lets 4% of E go through), and the Al fork
> and carbon fork have the transfer coefficients of 0.8 and 0.4,
> respectively (both at least an order of magnitude higher than the tire).
> Without considering the other components, shouldn't the rider receive
> 0.032*E of the shock energy due to the Al fork and only 0.016*E due to the
> carbon fork?
I like Chalo's response. But it isn't entirely one or the other. Each
piece is partially a damper, and partially a spring. I would suggest that
in that case, still, the stiffer component will act as if it is rigid in
the model.
But the rationale I would use for your argument is that the tire is not merely going to let
a fixed percentage of the vibration through; how much gets through depends
on pressure, tire brand, etc. Those variations are each larger than the
possible damping of a fork. So, how can the fork material matter?
> In other words, if
> I can feel the difference without the tire, I should feel the same
> difference with the tire.
Another good way to experience this is to rest the fork end on the ground,
and see how much "compliance" there is in the fork then. The bars will flex
much more. The stem will flex much more.
--
David L. Johnson
__o | The lottery is a tax on those who fail to understand
_`\(,_ | mathematics.
(_)/ (_) |
David L. Johnson
> If only I could turn back the clock 20 years, and we could have a
> discussion about the dangers of the improperly-designed steel forks out
> there...
You know, this reminds me of another thread, where Jobst was talking about
a failed Cinelli fork. That would be a steel fork that failed while,
possibly, just riding along.
>> There are people in the local cycling club who have had carbon fork
>> failures while "just riding along", complete with medical bills. --
>> terry morse Palo Alto, CA http://www.terrymorse.com/bike/
But there are a _lot_ of carbon forks out there now, and I have yet to see
one that failed with no accident or other damage to cause it. It really
can't be that common a thing. Possible? Sure. Common? No.
--
David L. Johnson
__o | "What am I on? I'm on my bike, six hours a day, busting my ass.
_`\(,_ | What are you on?" --Lance Armstrong
(_)/ (_) |
David L. Johnson
> On Thu, 04 Sep 2003 19:13:31 GMT, Werehatrack <rau...@earthWEEDSlink.net>
> wrote:
>> if the currently fashionable material or technique is X, then everyone
>> rushes to get out a product made using X *even if it's shoddy*, simply
>> because there will be demand for that product. It happened with radial
>> tires thirty years ago, it happened with front-wheel-drive cars
>
> Are you saying that radials or front wheel drive are shoddy, or just that
> everybody went out and got them without thinking for themselves?
I believe the idea was that _some_ radials were/are shoddy, and still sold
because they were radials. On the other hand, if you think front-wheel
drive cars are superior, you miss the point. Front wheel drive cars are
easier to assemble, lighter (less steel to buy and machine). That is why
they are the majority of the market now, not because they are in any sense
better. They are _sold_ somehow as being technically superior, but they
aren't.
>
> I'd argue that, while I've never driven on bias-ply, radials have been
> great to me; and have you ever driven rear wheel drive on highways with
> black ice?
I have driven both (and 4wd) on black ice. It doesn't matter what wheel
is connected to the engine; you slide when you try to stop or turn. In my
old rear-wheel drive I was better able to climb hills coated with black
ice than most of the front-wheel drive cars.
--
David L. Johnson
__o | What is objectionable, and what is dangerous about extremists is
_`\(,_ | not that they are extreme, but that they are intolerant.
(_)/ (_) | --Robert F. Kennedy
Jeff Starr
> I think it makes a huge difference. Isn't this ancient history? Practically
> no one buys a steel bike anymore and most forks are made out of aluminum or
> carbon fiber, with the steerer tube being the only part of the fork being
> steel. With the large volume of carbon forks being sold today, if there
> were a problem with them, it would be common knowledge by now.
> "Practically no one buys a steel bike anymore" <
Really? I just bought one and my guess is that a lot Steel LeMonds
were sold this year. It would be interesting for some of the dealers
to comment, on rough percentages. My guess is that aluminum is first
with either carbon fiber or titanium last, putting steel is second
place. This is just my guess, based on the bikes I see at my LBSs.
Life is Good!
Jeff
Mark Hickey
>"Mike S." <mikeshaw2@coxDOTnet> wrote in message
>news:8LV5b.44436$cj1.8770@fed1read06...
>>
>> This goes back to the question from a few days ago in the "OK hands up"
>> thread. If you haven't ridden something extensively, what makes you an
>> expert on that particular piece of equipment? (I'm not bashing Jobst
>> specifically here, mind you.)
>
>No, you're bashing science and engineering. The whole purpose of these
>disciplines is to create models from which behavior can be accurately
>predicted. The bicycle frame doesn't require a very complicated model.
The way I look at it is, if someone claims something is happening
(i.e. a frame gobbling up road shock), then they should be able to
describe a mechanism that allows that to happen. If you can't explain
the mechanism behind a seat stay compressing / damping / flexing
enough to be significant to ride quality, it seems like a reach to
still claim it affects the ride quality like it DOES compress / damp /
flex.
>> All right, I'm done bitching. Now for the recommendations: if you're
>> bashing something GO OUT AND RIDE IT. Ride it for several weeks/months.
>> Test it against your personal benchmark bike. Keep an open mind when you're
>> testing it, THEN let us know what you think. What are the plusses, minuses?
>> At least then we can have an opinion of someone with no reason to try and
>> sell us something.
Except that study after study have shown that human perception is (by
far) the worst way to try to quantify something. Throw a set of
sound-sealing headphones on next time you ride in your car and see how
much better it "rides" (this really works - of course it doesn't
really change the "ride", but it still seems like it). Put earplugs
in on your next ride and see if it doesn't change the "ride" of your
bike remarkably. Seriously.
>All this would do is give another subjective opinion. I've heard the same
>arguments in the steel vs.. aluminum debate. I've ridden both, and detected no
>difference, but since that's only another subjective opinion, I wouldn't
>expect it to prove anything. I haven't got the time, inclination, or
>disposable income to try every bicycle permutation on the market, even if it
>would prove anything. I don't need to, that's the whole point of science and
>engineering.
FWIW, I still own an old Cannondale with a steel fork. When I
concentrate and ignore the everything else, I can't say it rides at
all better or worse than my carbon forked ti bike. The sensations
coming up through my hands and rump seem pretty much identical. I
wish I COULD say there was a big difference - it might help me sell
more bikes.
jobst....@stanfordalumni.org
>> If only I could turn back the clock 20 years, and we could have a
>> discussion about the dangers of the improperly-designed steel forks
>> out there...
> You know, this reminds me of another thread, where Jobst was talking
> about a failed Cinelli fork. That would be a steel fork that failed
> while, possibly, just riding along.
This occurred twice and each time one fork blade cracked at the rear
at the point where the internal lug of the Cinelli fork crown ended
abruptly, internal lugs not being accessible to file them to feather
out the way external lugs are treated. This was not a crash inducing
event, since the crack closed upon applying the brake to stop. I was
amazed how well a bicycles handles with only one fork blade.
>>> There are people in the local cycling club who have had carbon
>>> fork failures while "just riding along", complete with medical
>>> bills.
> But there are a _lot_ of carbon forks out there now, and I have yet
> to see one that failed with no accident or other damage to cause it.
> It really can't be that common a thing. Possible? Sure. Common?
> No.
As I said, riders with whom I ride witnessed failures in which the
fork disintegrated, not just got soft or had one fork blade fail. The
front wheel was not attached to the bicycle. Of course not every fall
is a serious one, especially when the rider is under age 30.
Jobst Brandt
jobst....@stanfordalumni.org
Qui si parla Campagnolo
True for carbon forks but all the 'big boys' are seeing the resurgence of steel
sales, even Trek-oyota. Interbike last year and a lot of new steel framesets,
and I suspect that will be the same this year. many are remembering what a good
deal steel is. We sell as much steel as carbon, BTW-
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Fred Clydesdale
vecc...@aol.com (Qui si parla Campagnolo) wrote:
> deal steel is. We sell as much steel as carbon, BTW-
is that by weight or by volume? :)
Mike S.
> carbon fork when you rode it?
>
Actually, thinking about this question a little further yesterday, I had
carbon forks on my 2 road bikes, then got the 'cross bike with a steel fork.
I hadn't ridden a steel fork in years, so the difference was noticeable: the
slight "buzz" was back in the handlebars. It wasn't bad, just different.
So, I didn't upgrade to a carbon fork, I had a bike with a steel fork come
into the stable. Since there wasn't any expectations that a carbon fork
would ride different, there is no reason for me to "pre-decide" how it was
going to ride.
That there is a difference in the ride between a steel fork and a carbon
fork is a given. It isn't much, but there is a difference. I haven't
ridden a carbon rear triangle bike, so cannot draw any conclusions about
them. If my little brother's butt is accurate, they ride a little
differently than AL rear triangles.
Mike
Rick Onanian
wrote:
> Practically no one buys a steel bike anymore and most forks are made out
Fabrizio? Izzat you?
--
Rick Onanian
Rick Onanian
<david....@lehigh.edu> wrote:
> because they were radials. On the other hand, if you think front-wheel
> drive cars are superior, you miss the point. Front wheel drive cars are
Front wheel drive cars are superior for some people
in some situations.
They certainly aren't the one-size-fits-all perfect
technology that some people think they are.
> easier to assemble, lighter (less steel to buy and machine). That is why
...and allow transverse engine mounting, which
results in a shorter hood, allowing a car of the
same size/weight to have more interior room or
to be shrunk.
Weight is so important because of the regulations
requiring fuel economy and emissions standards.
Reducing weight is one of the most effective ways
to achieve those goals, especially when other
technologies can be rather expensive.
> they are the majority of the market now, not because they are in any
> sense better.
I wholeheartedly agree.
>> great to me; and have you ever driven rear wheel drive on highways with
>> black ice?
>
> I have driven both (and 4wd) on black ice. It doesn't matter what wheel
> is connected to the engine; you slide when you try to stop or turn. In
Yes, that's true. However, I had the scary experience
of being a passenger in a 2wd pickup going along
steadily on Route 95; flat, level, straight; driver
was consistent and did not accelerate; but when the
drive wheels hit a patch of black ice, we ended up
in a ditch.
This was because, while not accelerating, it was
(of course) necessary to provide power to the drive
wheels to continue at the existing speed. When they
hit the low-traction patch, they spun and broke
loose, and so lost lateral as well as forward
traction.
> my
> old rear-wheel drive I was better able to climb hills coated with black
> ice than most of the front-wheel drive cars.
Was that the car, or the driver?
Further, if properly equipped (chains, etc), I
expect the RWD would be better than FWD, due to
weight distribution on a steep hill (as
bicyclists, we know that if you don't change the
weight distribution when changing the grade, the
center of gravity moves down the grade).
--
Rick Onanian
Rick Onanian
> The way I look at it is, if someone claims something is happening
> (i.e. a frame gobbling up road shock), then they should be able to
> describe a mechanism that allows that to happen. If you can't explain
No, if they clame their frame is gobbling up road
shock, they should get out and ride and enjoy it.
We should all get out and ride instead of being here.
> Except that study after study have shown that human perception is (by
> far) the worst way to try to quantify something. Throw a set of
Human perception is by far the best way to
quantify one thing: human perception! Who cares
how the bike scientifically, quantificatively (is
that a word?) rides; we're talking about how a
human is going to like a bicycle, so what matters
is...how humans like their bicycles!
The issue with human perception is that we then
take it as fact that our perception will be the
same as somebody else's. That's why it's good to
back it up with hard, quantified facts; then we
can say that it's more likely to feel the same.
However, to discount what goes on in the human
mind, is defective logic here. It's more
applicable in places where a quantified
improvement is more important than a perceived
improvement.
I certainly ride bikes that I perceive to be
better much more than I ride bikes that may
actually be better. Okay, who am I
bullshitting...I don't have that many bikes to
ride and be able to say that! <G>
> sound-sealing headphones on next time you ride in your car and see how
> much better it "rides" (this really works - of course it doesn't
> really change the "ride", but it still seems like it). Put earplugs
This is 100% true. Note, however, that to do so is
most likely illegal where you are (it probably is
everywhere).
> in on your next ride and see if it doesn't change the "ride" of your
> bike remarkably. Seriously.
That is also illegal.
Yet, it's legal to drown out sirens and horns with
your radio. Okay.
> Mark Hickey
> Habanero Cycles
> http://www.habcycles.com
> Home of the $695 ti frame
--
Rick Onanian
Tim McNamara
Rick Onanian <spam...@cox.net> wrote:
> On Sat, 06 Sep 2003 05:40:58 GMT, Mark Hickey <ma...@habcycles.com>
> wrote:
>
> > Except that study after study have shown that human perception is
> > (by far) the worst way to try to quantify something. Throw a set
> > of
>
> Human perception is by far the best way to quantify one thing:
> human perception!
Actually, the field of human perceptual research is quite fascinating.
I'd wholeheartedly recommend reading James J. Gibson's _The ecological
approach to visual perception_ which covers a lot more than visual
perception, despite its title.
> Who cares how the bike scientifically, quantificatively (is that a
> word?) rides; we're talking about how a human is going to like a
> bicycle, so what matters is...how humans like their bicycles!
Well, for the rider it makes little direct difference. For the bike
designer it makes a lot of difference. Being able to quantify the
factors that give a bike its characteristics means that it is easier
to design bikes people like to ride.
> The issue with human perception is that we then take it as fact
> that our perception will be the same as somebody else's. That's why
> it's good to back it up with hard, quantified facts; then we can
> say that it's more likely to feel the same.
Our perception is likely to be very similar, given the fundamental
similarity of our sensory systems. Someone who has a functional
difference in one or more of their sensory systems will have a
somewhat different perceptual experience- e.g., someone being color
blind.
The main benefit of quantification is to be able to predict what
various changes in bike design will do to how the bike rides. Now,
probably like you and certainly like a number of others in r.b.t., I
am curious and want to understand those factors as well as I can.
That's why we have these interminable and sometimes acrimonious
threads. ;-)
> However, to discount what goes on in the human mind, is defective
> logic here. It's more applicable in places where a quantified
> improvement is more important than a perceived improvement.
Quantification facilitates prediction of perception (I really have to
stop repeating myself and saying the same things over and over in the
same post...).
A Muzi
news:Xns93ED880721675mf...@130.133.1.4...
> Practically no one buys a steel bike anymore
Gee I should get out more.. Really? About 80% steel here. . .
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
Mark Hickey
> If my little brother's butt is accurate, they ride a little
>differently than AL rear triangles.
If there's a calibration process, I DON'T want to know about it...
;-)
Qui si parla Campagnolo
hmmm-another example of the mounds of misinformation about steel that exists
now. Weigh a steel frameset, then a middle ground aluminum, and then a low end
Ti-
Fred Clydesdale
vecc...@aol.com (Qui si parla Campagnolo) wrote:
> fred-<< is that by weight or by volume? :) >><BR><BR>
>
> hmmm-another example of the mounds of misinformation about steel that exists
> now. Weigh a steel frameset, then a middle ground aluminum, and then a low end
> Ti-
hey, i was ( :) :) :) ) joking. in fact, though i have one of those
hi-tec monocoque CF frames, my favorite is lugged, butted ishiwata
steel. rock-solid and beautiful to look at, with those beautifully
finished 3-point lugs.
fc
A Muzi
news:20030907104348...@mb-m25.aol.com...
> fred-<< is that by weight or by volume? :) >><BR><BR>
>
> hmmm-another example of the mounds of misinformation about steel that
exists
> now. Weigh a steel frameset, then a middle ground aluminum, and then a low
end
> Ti-
My customers think I'm trying to pull something shady when I hand them a
damn-near-same-weight Habanero titanium and a Gunnar Reynolds 853 or Soma
631 steel off the rack. These are similarly priced frames. The "common
knowlede" that "steel is heavy" might be correct for railroad rails and
manhole covers but not so much for the kind of steels used in EAA aircraft
and bicycles. Except for a couple of dare-to-be-different, motorcycles are
still steel framed, and so are cars (when they have any frame at all). Not
that alternates haven't been pursued, but steel is just a very suitable
material given the spectrum of constraints in these problems.
Dave Lehnen
> ="Qui si parla Campagnolo" <vecc...@aol.com> wrote in message
> news:20030907104348...@mb-m25.aol.com...
>
>
> My customers think I'm trying to pull something shady when I hand them a
> damn-near-same-weight Habanero titanium and a Gunnar Reynolds 853 or Soma
> 631 steel off the rack. These are similarly priced frames. The "common
> knowlede" that "steel is heavy" might be correct for railroad rails and
> manhole covers but not so much for the kind of steels used in EAA aircraft
> and bicycles. Except for a couple of dare-to-be-different, motorcycles are
> still steel framed, and so are cars (when they have any frame at all). Not
> that alternates haven't been pursued, but steel is just a very suitable
> material given the spectrum of constraints in these problems.
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
>
>
The most common frame for high-performance motorcycles (sportbikes)
has been twin-spar aluminum for quite a few years now. For that
matter, even the current model of the enormous Honda Gold Wing
touring bike is twin-spar aluminum. There are still some exceptions
in sportbikes, notably the very successful Ducati steel trellis frames.
No argument that steel is still a very suitable material for bicycle
frames.
Dave Lehnen
Rick Onanian
wrote:
> Well, for the rider it makes little direct difference. For the bike
> designer it makes a lot of difference. Being able to quantify the
> factors that give a bike its characteristics means that it is easier to
> design bikes people like to ride.
Ah hah! There's a point that I missed.
> Our perception is likely to be very similar, given the fundamental
> similarity of our sensory systems. Someone who has a functional
> difference in one or more of their sensory systems will have a somewhat
> different perceptual experience-e.g., someone being color blind.
There are other differences. I don't perceive a
bike with oversize aluminum tube frame and narrow,
high pressure tires to be harsh. Others do.
OTOH, others perceive handlebars that are 12" lower
than the saddle to be comfortable; my neck, hands,
and shoulders don't like it much more than 2" lower.
Even that's pushing it.
> The main benefit of quantification is to be able to predict what various
> changes in bike design will do to how the bike rides. Now, probably like
Yes, that's true. Putting numbers on it makes it
more scientific to guess what's going to happen
in the future, as well as what will sell better
to more people.
> you and certainly like a number of others in r.b.t., I am curious and
> want to understand those factors as well as I can. That's why we have
> these interminable and sometimes acrimonious threads. ;-)
Indeed, I suppose it is. I suppose it's also
good to occasionally step back and change our
point of view, as in this discussion.
>> However, to discount what goes on in the human mind, is defective logic
>> here. It's more applicable in places where a quantified improvement is
>> more important than a perceived improvement.
>
> Quantification facilitates prediction of perception (I really have to
> stop repeating myself and saying the same things over and over in the
> same post...).
You can certainly repeat yourself at least as
much as I repeated myself.
However, in that section, I was NOT pointing out
that we must ignore quantification (we shouldn't);
rather, I meant to stress that we should INCLUDE
human perception as a major factor in such things
as "ride quality" and "performance".
In fact, I would say human perception is the most
important factor in "ride quality". It's how _I_
determine whether I like a bike's ride quality or
not.
--
Rick Onanian
Mike S.
That's assuming that the points of view are able to be changed... Sometimes
that just won't happen, no matter how much evidence to the contrary there
is.
> >> However, to discount what goes on in the human mind, is defective logic
> >> here. It's more applicable in places where a quantified improvement is
> >> more important than a perceived improvement.
> >
> > Quantification facilitates prediction of perception (I really have to
> > stop repeating myself and saying the same things over and over in the
> > same post...).
>
> You can certainly repeat yourself at least as
> much as I repeated myself.
>
> However, in that section, I was NOT pointing out
> that we must ignore quantification (we shouldn't);
> rather, I meant to stress that we should INCLUDE
> human perception as a major factor in such things
> as "ride quality" and "performance".
The engineers can argue all they want that a change in a material makes X
difference on the test bench, so should make Y difference on the road. The
thing they keep forgetting is that it isn't an instrument riding the
bicycle, it is a human with all of the foibles, pre-conceived notions, and
whose arse isn't calibrated the same as the test instrumentation.
All the testing in the world don't help if the human actually riding the
bike doesn't like the "ride quality."
> In fact, I would say human perception is the most
> important factor in "ride quality". It's how _I_
> determine whether I like a bike's ride quality or
> not.
>
> Rick Onanian
Rick Onanian
> damn-near-same-weight Habanero titanium and a Gunnar Reynolds 853 or Soma
> 631 steel off the rack. These are similarly priced frames. The "common
> and bicycles. Except for a couple of dare-to-be-different, motorcycles
> still steel framed, and so are cars (when they have any frame at all).
The difference, here, is that high quality bicycle
steel is priced competitively to other bicycle
materials.
Cars, and possibly motorcycles, have much lower
price for steel than other materials; if cars
could be made at prices competitive to Al or
Ti, there would be at least a few on the market.
> Not
> that alternates haven't been pursued, but steel is just a very suitable
> material given the spectrum of constraints in these problems.
Mainly, price. Weight per strength, Al is
stronger than the steels used in automotive
applications, AFAIK, but IANAE. Further, Al
in cars would eliminate most of the issues
that cars have with corrosion (though those
have been mostly eliminated with other,
cheap technologies for treating steel).
For bicycles, though, good steel is priced
similarly to good Al; and very good steel
or Al is priced similarly to Ti or CF; and
aside from all that, people will pay a much
larger range for different materials. In
cars, nobody will pay more for a lighter
material.
Anyway, IMO, a good frame is a good frame
no matter what material (though a good
steel frame might need to be changed to be
a good Al frame, etc).
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
--
Rick Onanian
David L. Johnson
> However, in that section, I was NOT pointing out that we must ignore
> quantification (we shouldn't); rather, I meant to stress that we should
> INCLUDE human perception as a major factor in such things as "ride
> quality" and "performance".
I might be persuaded to believe that there is some unmeasurable effect
that can be perceived as a "ride quality" difference -- might. It would
take some doing, such as a successful blind test, which no one has
offerred. Most "noticable differences" in ride quality are directly
reltated to the amount the rider spent on the new bike -- and the degree
to which he/she has to justify this expense.
But performance can be measured. The total lack of such measurements in
all the ads and promotion for new bikes is just as revealing as the
meaningless adjectives used to describe the effect of dropping a bundle on
a particular bike: "compliant" is my favorite. While I certainly would
not like a bike that disobeyed me, I'm not sure what sort of units
compliance should be measured in.
--
David L. Johnson
__o | Let's not escape into mathematics. Let's stay with reality. --
_`\(,_ | Michael Crichton
(_)/ (_) |
Rick Onanian
> The engineers can argue all they want that a change in a material makes X
> difference on the test bench, so should make Y difference on the road.
> bicycle, it is a human with all of the foibles, pre-conceived notions,
Thank you. That is a major part of what I was
trying to say, and very well said.
> All the testing in the world don't help if the human actually riding the
> bike doesn't like the "ride quality."
...which is why, when somebody says "but I CAN
feel the difference", it doesn't matter that
he shouldn't be able to feel it. If he thinks
that he does, that's good enough for him!
--
Rick Onanian
jim beam
> stronger than the steels used in automotive
> applications, AFAIK, but IANAE.
http://www.reynolds-cycle.com/internet/english/tech/tube.htm
check this out and scroll down to the "specific stiffness" table. i.e.
stiffness/weight. notice how similar the "normal" al & fe alloys are.
the only alloys offering significant advantage are the [expensive]
exotics.
Rick Onanian
<david....@lehigh.edu> wrote:
> I might be persuaded to believe that there is some unmeasurable effect
> that can be perceived as a "ride quality" difference -- might. It would
It would be entirely psychological. Even as such,
it's still valid.
> take some doing, such as a successful blind test, which no one has
Blind testing would be neato. I suspect the
gimmicks and such would not have much of an
advantage.
> offerred. Most "noticable differences" in ride quality are directly
> reltated to the amount the rider spent on the new bike -- and the degree
> to which he/she has to justify this expense.
Possibly, but if it makes them want to ride more,
who cares?
> But performance can be measured. The total lack of such measurements in
Define performance. I'll bet it depends so much
more on the rider than the bike.
Comfort, enjoyment, excitement, and status are
what people buy in a bike. Performance is often
a label for excitement.
Disclaimer: I'm talking out of my ass. I could
very well be wrong, but this is my take on what
I observe.
> all the ads and promotion for new bikes is just as revealing as the
> meaningless adjectives used to describe the effect of dropping a bundle a
> particular bike: "compliant" is my favorite. While I certainly would
> not like a bike that disobeyed me, I'm not sure what sort of units
> compliance should be measured in.
Hmm...
"The new Slavemaster 2000 gives a 23 whip ride!"
"The Trek S&M has a black leather saddle rated
for at least 300 slaps!"
Good point.
--
Rick Onanian
Terry Morse
> http://www.reynolds-cycle.com/internet/english/tech/tube.htm
>
> check this out and scroll down to the "specific stiffness" table. i.e.
> stiffness/weight. notice how similar the "normal" al & fe alloys are.
That table, while accurate, doesn't reflect the large stiffness
benefit of aluminum over steel. For a given weight, an aluminum tube
can be made with a much larger diameter than a steel tube, making
the aluminum tube much stiffer in bending. Steel could be used to
make a tube of the same diameter, but it would be too fragile.
Rick Onanian
Bicycle frame tubing is a VERY different application
from automotive frames / bodies, and uses VERY
different alloys to boot.
Further, there's more to strength than stiffness.
Jobst probably knows all about it, I don't.
However, like I said, it's mainly price.
--
Rick Onanian