in article
[email protected], Kraig Willett at
[email protected] wrote on 5/17/03 5:30 PM:
> No testing is actually required, is it? I thought that it was up to the mfr's to be certain that
> the products they sell/spec are safe enough.
There is a difference between testing to ensure that products are safe and product development.
Testing only requires a sound test protocol and the resources in order to carry out the testing.
Product development requires much more.
> Based solely on the snippets provided, I would not come to the conclusion that the company behind
> them doesn't know what they are doing from an engineering/design standpoint.
Oh? You have no problem with the claim that they "mechanically butt [sic]" the tubing "tune the
response you feel from the ride?" Do you believe that their engineers designed the tubing to do this
and were able to verify the results in a scientific manner? If so, why not show us how. Since they
are making the claimm, they carry the burden of proof.
They would have to define what they mean by "ride," show that they have the ability to affect it by
varying wall thickness, and then show that the change in "ride" is significant enough to be
noticeable by the rider.
Their claims about their "shaped tubing" are even more ridiculous. They are merely copying the style
of oversized aluminum frames which are ovalized purely for the purpose of being able to join tubes
of different sizes. You aren't going to be able a 1.5" diameter tube to a 1.125" diameter tube
without squishing the larger tube to fit. Of course, the aluminum manufacturers tried to turn this
into a marketing advantage years ago by making similar claims.
Still, let's take a look at what they say: "The down tube is ovalized at the bottom bracket to be
laterally stiff under pedal loads and vertically compliant to road shock. The top tube is ovalized
at the seat tube to isolate the rider's weight while the round sections absorb road shock."
You don't need to be an engineer or have fancy test equipment to understand that the pedaling loads
on the down tube are mostly torsional, not lateral. An ovalized tube will have LESS torsional
stiffness than a round tube of equivalent size. But, hey, the horizontal ovalization makes it
"vertically compliant" (despite the fact that a bicycle frame is an inherently stiff structure in
the vertical plane) yet the vertical ovalization at the top tube doesn't seem to cancel that out.
Instead, it isolates the rider's weight. What the hell does THAT mean?
You and I both know that the ovalization of tubing here is done purely for marketing copy. If they,
or any of the other companies who use similarly ovalized tubing, can provide some data to back up
their claims, I'd like to see it.
> If these claims bother you so much, why don't you actually _do_ something about it besides
> complain on a public forum?
If I had the resources to do so, I would. There are a number of folks who are making an effort to
expand the knowledge base of our industry. Some have participated in the Hardcore Bicycle Science
mailing list which unfortunately is no longer active. This list included a number of engineers and
designers and was a fairly good exchange of ideas and information. Damon Rinard conducted a number
of tests and published the results and most of his test protocols on his website (now on Sheldon
Brown's site). I provided some wheels for his lateral wheel strength tests.
Still, we can take what is already known about materials and design and apply them to the claims
made by these companies. Many of the claims contradict what is generally accepted to be true. This
does not automatically invalidate the claims, but it does place the burden on those making the
claims to provide data to back them up. I have seen lots of claims and virtually no data.
> I _do_ know that Trek/LeMond has competent engineers, and to imply otherwise is, IMHO,
> disingenuous.
I used to work in product management at Motorola and am quite familiar with engineers, engineering,
and the product development process. Trek/Lemond may have engineers, but I'm not quite sure what it
is that they do. Unlike engineers in other fields, they do not publish any of their research and
their patent filings are quite limited. What has been filed lacks much engineering data.
If the engineering were as competent as you suggest, I doubt that we would have seen the large
number of OCLV failures over the years. That particular product development was tested by their
customers and refined through feedback from the warranty department. Whatever engineering and
testing they did was certainly inadequate in that case.
Todd Kuzma Heron Bicycles LaSalle, IL
http://www.heronbicycles.com/