Originally Posted by
Drew Eckhardt
Sure. A 160 pound rider would be nearly 8% faster up the steepest hills on a 20 pound bike than a 34 pound one. On hills where he could only manage 10 MPH before he could go 10.8 MPH, and he'd be nearly 4.5 minutes faster to the summit of a hill that used to take an hour to climb.
Almost, yes, if he's going slowly enough. But not at 10 mph is where the difference will become less as the aerodynamic drag becomes important.
It's not that weight is irrelevant. It's that it is exactly as important as it is, and most people overestimate it.
Bike calculator web pages are great for answering these questions.