Originally Posted by
jethro56
IMO: I suspect it's the reduction of rotational mass (flywheel effect) that makes them feel lighter. The Trek 2.3 Al felt as quick as the 4.5 Madone CF bike I rode back to back when making my final decision.
I hadn't thought about that but it makes sense. The reduced wheel weight would make it easier to spin up to speed thus making it feel more light and responsive. I assume (but don't have the engineering to know for sure) that the reverse would be true in forward motion while coasting leading to a net zero (if overall weight was the same). But that would at least account for the feel. One of the reasons I wondered about this is that I have lost 15 pounds over the past year but my bike feels the same as ever. I recognize that this is a gradual reduction but still... On this rotational mass theory, however, the spin up requirement would be unchanged so the feel would be unchanged despite my weight loss.