Originally Posted by
Dryvlyne
I'm curious, how much does reduced bike weight translate into a speed increase?
If anyone knows of a study that looks specifically at this I'd be very interested in that. Otherwise just anecdotal feedback from users that have gone to a lighter bike would be great; how much did your avg pace improve?
I weigh 138 pounds, have an FTP of at least 210 Watts, and that combination is good for about 22MPH on flat ground in a straight line or 20 once you throw in bumps and turns around which you can't pedal.
Analytic Cycling Speed Given power agrees - try .4 m^2 Sd, .760 Cd from Gibertini and Grassi's paper, 71.2 kg, and .004 Crr which is close for nice tires - 9.93 m/s, 22.2 MPH
On a 6% climb that's 4.35 meters/second, 9.7 MPH.
Dropping bike weight to 15 pounds for 69.4 kg total weight would net 9.94 meters/second or 22.2 MPH on flat ground and 4.45 meters/second, 10.0 MPH up-hill. That's a 2.2% speedup and good for 41 seconds an hour on an up-hilll time trial like the Mt. Diablo Challenge.
Heavier riders will see smaller gains.
IOW, for practical values of "lighter" it usually does not matter.