Originally Posted by
exmechanic89
^This I believe is the answer. IMO it's not possible to have such a large difference in mph with such minor differences in the bikes involved, no matter how the figures are tossed around and calculations are made. I've had large differences in mph myself on the same bike many times, and I always chalk it up to differences in how I feel that day.
I remember when I still had my BD bike, which was 5 lbs. heavier than the Klein which I still have- . I'd often turn in the exact same times on a ride as I did/do on the Klein. Actual performance differences between bikes are so subtle (unless we are counting mere seconds) that our physiology and psychology make a far bigger difference. Sometimes just thinking that a bike is "slower" will make us slower on that bike; or knowing that a bike weighs more than another will make it "feel heavier"- but if it were possible to do a blind comparison, in reality, we wouldn't even notice the difference in a few pounds, or a few millimeters in tire width, etc. But when our brains tell us "what should be", we often self-fulfill the prophecy.
The best solution, is not to weigh your bikes; and idealy, to ditch the bike computer. (I haven't gone as far as the latter, yet...)
I remember when I had my Venge- it "felt" really fast- but my times on it were always within the same range as what I'd do on the BD or the Klein- and we're talking at that point, a range in bike weights from 17-24 lbs.!