(1) I ride rollers for training. Although the model probably is not relevant, they are Elite E-Motion B+ which are ANT+ FE-C controlled by TrainerRoad.
(2) I have two very similar bikes that I put on the rollers with identical frame geometry, saddle height, pedals, etc.
- (a) Pinarello GAN RS with RED Etap 11/28 and (temporarily) Vueltra Ultra Light wheels, wearing Gatorskin 700x25 @ 95psi
- (b) Pinarello GAN RS with Di2 11/32 and HED Ardennes Plus SL, wearing Continental GP 4000s II 700x25 @ 95psi.
Now, the meat of the question:
If I ride the exact same TrainerRoad program but swap the bikes, "Pinarello B" with the 11/32+Ardennes+GP4000 allows me to produce significantly higher watts for a longer period of time. Why?!? Is it the gearing of the 11/32 ? Doesn't make sense because I'm never in the 32 on the rollers. Is it the rim width of the Ardennes? Doesn't make sense because the rubber on both bikes is 25mm. Is it the rubber compound of Gatorskin vs. GP 4000 ?
Dozens and dozens of roller rides over the past year have confirmed this feel, and the TrainerRoad data backs it up --- I'm riding (no b.s. here) roughly 30 watts higher on a 1-hour workout when using "Pinarello B". Full disclosure, 5'9" 66kg, FTP 260
Educate a dummy. I don't understand.