Originally Posted by caloso

It's hard to quantify. Some of the improvement is likely to be psychological: You feel faster and stronger, so you are faster and stronger. I admit that I do this myself sometimes. Saturday I put my race wheels on my bike to go on the River Ride. I'd gotten dropped the week before and I wanted to save as many watts as I could. Plus, I've hardly raced at all this year and it seems a shame to keep these wheels just hanging in the garage. Did those wheels mean the difference between getting dropped or not? Probably not. But maybe they helped a little bit too. It's just impossible to quantify.