Originally Posted by
blacknbluebikes
You're the engine, so remember that as the "first factor" regardless of what's under you. Second, weight is a bigger factor than stiffness. I'd rather climb with a 15lb aluminum bike than a 23lb carbon bike any day. Third, it's easier for me to lose 3lbs than it is to make a 23lb bike become a 20lb bike (cheaper, too). Fourth, I only hear sprinters fussing about stiffness, rarely climbers.
True, but riding a lighter and stiffer bike can make a big difference in how fast it
feels when climbing.
I test rode a Serotta Ottrot about 15 years ago, and I was riding (still ride) a 1995 Cannodale T700 (aluminum frame touring bike). The weight difference between the two bikes was probably in the neighborhood of 10 lb, my touring rig had 35mm tires while the Ottrot had 23 mm tires, the bars on the Ottrot were significantly wider, etc. Was I faster while climbing? Definitely. Was the difference "significant"? Well, I was no threat to the Tour de France riding either bike so, no, not really. However, the difference in feel was like night and day. I felt like I was flying up the climbs. One climb that I normally had to take out of the saddle on my Cannondale in a 32 x 25 gear I was spinning in the saddle on the Ottrot in a 39 x 25 gear.
I guess I'd answer the OP's question by saying that, objectively there may be a small but measurable increase in speed and that subjectively there could be a "significant" difference. The magnitude of the objective and subjective differences depend on many factors, including not only the differences in weight and "stiffness", but in tires/tire pressure, relative weight of the wheels, width of bars, etc. - even differences in stand-over height can have an effect on how fast a bike feels.