Originally Posted by
horatio
I'd always heard the efficiency (vis-a-vis power) was due to stiffness from the short seat stays.
Most of the old C'Dale, and other early aluminum framed bikes, was due to using straight gauge tubing. In order to achieve the same stiffness as quality steel, double butted, tube sets, they had to use large diameter aluminum tubes. with modern tube manufacturing techniques the interior profiles and the tapers visible on the outside can be manipulated. Hydro-forming allows butting and other exotic interior profiles, as well as the unique tapers being done by CIM methods. The early C'Dales had some large down tubes and top tubes, and the stays had thick walls to keep them from being noodlely.
On my CAAD 10, you can actually press the down and top tubes with your thumb and see it flex in the larger diameter sections, away from the butting at the ends. Alloys and manucturing techniques have come a really long ways since the first Klein and Cannondale big tubed, stiff feeling types. But, I agree about how the large tubed bikes were appealing to look at, I drooled over a test of a prototype Klein in 1978 Bicycling magazine for several months.
Bill