Originally Posted by grolby

Nope, it's not that important in crits, either. The difference in the power needed to accelerate wheels with heavy rims vs light rims, if you hold the total weight equal, amounts to fractions of a watt.

Which makes sense, if you step back and think critically for a minute. When you accelerate a bike, you are not spinning up a pair of 1400 gram wheels. You are trying to accelerate your 150 lb butt up to speed. Rotating mass has some influence, but it is very slight. The biggest factor by multiple orders of magnitude is how much torque you can produce.