Steve Maas wrote:
> Similarly,
>
> The fact that aluminum and carbon frames in this test lasted
> longer than the steel frames is not in our estimate a question
> of the material, but the design effort.
>
> How do they know what design effort went into the frame? Was there some extra information about this? They didn't present any.
When we were designing the first Trek bonded Al frame back in the early 1980's we built a stress testing machine similar to what Damon shows on his web site. The model "2000" Al frame was designed to have riding characteristics similar to a steel frame (in part to avoid problems with Klein's patent on using oversize tubing to increase frame stiffness). The prototypes for this model were tested on the machine to demonstrate that the frame and bonded joints would be at least as durable as those of a steel frame of similar geometry.
There were many other tests as well -- one of the prototypes was built up and a rider rode the bike on an abandoned railroad track from Waterloo to Sun Prairie and back (about 20 miles round trip) over the ties to test a worst-case rough ride scenario. We also did comparative road tests of bikes -- I remember we used a Trek 970 (Columbus SL/Campy Super Record), a top of the line Cannondale, a Vitus Al frame with Campy Super Record, Gary Klein's personal road bike (which I got to ride), and the new Trek 2000 with Dura-Ace SIS (new that year).
All the bikes rode very nicely, although I personally found the Cannondale and the Klein too harsh for my taste -- I only weighed about 135# back then and when I hit bumps on the Cannondale and Klein I found them hard to control. Heavier riders didn't seem to have a problem. The Vitus was definitely the most flexible, but that didn't seem to be a problem in real life -- look at all the Columbians who won mountain stages on Vitus frames. And the Trek rode very much like a steel frame, just as it had been designed to do.
--
-John Thompson (john@os2.dhs.org)
Appleton WI USA