Originally Posted by steve_wmn
Maybe, maybe not. It's entirely possible that the differences in RR found by measuring on a smooth drum would be lost in the noise on a rougher surface. I wish I could find the study that said that higher pressures don't always yield better RR on a real road. Looking at Jobst's data it's clear that the tubulars have flatlined at 130 psi, and probably wouldn't go any lower in RR at a higher psi even on a smooth surface. Clincher RR was still going down at 130 but appears to bottom out at 150 psi on the analyticcycling.com charts of rolling resistance.
Interesting...for me the cutoff of increasing PSI in exchange for better rolling resistance is 120psi. Given my weight it seems I'll waste more energy fighting irregularities with pressures higher than 120psi to be worth any reduced rolling resistance. I guess you could also say that tire pressures too high can in itself create more "rolling resistance" from the tire not being able to conform to irregularities as well. As mentioned many times before, it's a fine balance between higher pressure while still being able to soak up some bumps.