Question about ride quality of aluminium with carbon stays

Jobst Brandt wrote:

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)



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http://diabloscott.blogspot.com

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David L Johnson wrote:
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?
I only mentioned that because your earlier resonse seemed to say that
the reviewers were not claiming better handling characteristics from
carbon forks, but they are - even if it is nonsense.


I’m not trying to be argumentative here,
Sure you are
I'll let that one slide.


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.
Honestly I have seen very few unfavorable reports about carbon forks
since the early Kestrel (?) models had a failure problem in the mid
'80s. Since then the failures I've seen were reported as anomolies.


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.
Actually for the Merckx example the more expensive one with the carbon
rear weighs 5 ounces more.

Thanks for your response.



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http://diabloscott.blogspot.com

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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.

Maurizio

Mark Hickey wrote:
"H. Guy" wrote:

In article ,
"Gearóid Ó Laoi/Garry Lee" wrote:

It's all in your imaginations chaps. All materials ride the same.
If people do not know what kind of frame they are riding, they
can't tell. It's been tested.

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)?

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.

--
Perre

You have to be smarter than a robot to reply.

Diablo- 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? BRBR

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.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

jim beam wrote:
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 flcl?

(Roy) wrote in message . 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.

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

David Damerell wrote:
jim beam wrote:
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 flcl?




Carbon stays will never make up for aluminum's deficiencies.



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BaCardi (?) wrote:

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/

I just went through a round of test riding a bunch of new bikes. I
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.



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?