just read the latest thread on the yaquis with great interest. i keep hearing about the value of the stiff rear triangle, and can’t help wondering, ‘so what?’ most of what triathletes do is fairly steady-state power output in a relatively low range. isn’t being comfortable enough to stay aero more important than having a stiff rear triangle? so, assuming one can get a bike that fits properly made from any material, does frame material become more important in the decision?
The stiffness in the rear triangle on my Yaqui at least partly comes from a robust carbon fiber seat-stay. “Comfort” and stiffness are not mutually exclusive.
Good design is what an athlete needs for their steed. Stiffness can be comfortable when engineered correctly. Frame material becomes important when the designer makes the best use of materials. A frame made of seatstays would certainly light, but would be such a noodle that even with the best geometry, it would be hellish to ride, let alone scary. A frame made of oversized DH mountain bike down tubes everywhere would be like a tank, and jar the fillings from your mouth. It’s all about the correct design.
Ves would say to you that the seat stays have little to no consequence on frame comfort. I first saw this concept on the Principia bikes. Ves confirmed this in conversations. This lead to my suspicion that one should get the stiffest stays on their bike, as I always hated a bike with a noodly rear triangle. I had one, and it fatigued me faster than any “bone jarring” Cannondale (the jarring nature of their ride is a bit overstated, in my opinion). Ves has the engineering pedigree and experience to say whether this is correct, and judging by the beefy nature of his carbon stays, I think my suspicion is correct.
I can tell you this- if it ain’t stiff enough, the frame will rob you of power, which can lead to fatigue and discomfort.