Originally Posted by
Mosquitolt
It may be due, to different sitting position, maybe BB was tight on the old frame and other marginal gains. 20w difference is realistic I think.
Remember that he's measuring power directly at the crank arm, not at the rear hub. So it doesn't matter about how tight the BB was or any other marginal gains related to the bike drivetrain. I agree a more favourable position might give a little more power, but a 20W average increase is actually pretty big. It would have to be a much better position.