>Bike weight isn't going to make a measurable difference on flat ground.
My comment was not really about the weight per se. The geometry of the frame has a significant effect on energy transfer...especially when climbing.
On a fast commute I spend half my time somewhere between 18 and 21 MPH spinning 50x21, 50x19, or 50x18.
since my commutes are short (5-10 miles one way) i have no problem sprinting at 30-35 mph on interspersed flats. i am more interested in irritating cagers, getting excercise, and maintaining a cadence of 90-120 (so i don't blow my knees) than developing obscene track skilz.
I also run my 25mm tires at 95-100 psi rear and 90-95 front with my 180 pounds of flab and 15 pound pannier.
I typically carry a very large ortlieb bag (laptop, tools, gear, lunch, groceries, case of wine) and am a 205 lb clyde with calves thicker than his skull.
or other road imperfections one of which was enough to bend a 400g rim.
I run R500s or cxp33s and have no problem with the higher psi (but both are heavier rims).