Originally Posted by
gsa103
The "significant" weight disadvantage was 524 gm. I'm going to make a ballpark guess that the bike weighs 15 lbs, they said the rider was assumed to weigh 170 lbs for a total mass of 83.9 kg. The extra weight is a 0.5% change in total rider mass. The rider is assumed to be putting out 250W, so to compensate for an extra 0.5% mass, the wheel will need to save 0.5% power (to first order), or a savings of 1.4W.
A savings of 1.4W at 8mph doesn't seem unreasonable considering people are routinely quoting 10+ W at higher speeds.
I think by "significant weigh disadvantage" springs was talking about the Flo90/Disc. 2259-1100=1159 gram difference. But even then, using your numbers at bikecalculator.com it is about an added 2 watts to get the 55 second disadvantage down to the 23 seconds they show.