Originally Posted by tetonrider

many good points. i think we're tossing around slower and faster. i was referring to rolling resistance, but when we talk about "faster" overall, the performance of a tire in corners as you note could come into play. a tire that rolls faster is not faster overall it if folds underneath the rider and causes a crash.

a few years ago i tested pressure on real-world roads. i'd done testing Crr testing on rollers (before and since) to compare rolling resistance of various tires and tubes. in theory, the results from smooth rollers translate to roads, but i wanted to see.

for my test i varied pressure while riding similar power (and corrected for it). i was riding up a steep, protected grade to eliminate or at least minimize the effect of wind. i dropped pressure from 120 on down to 80. never went below 80, but as i went lower each run was faster/i went further, adjusted for power. perhaps there is a point where distance traveled would go back down, but i didn't see it or see any evidence of it. (well, surely at zero pressure it would happen...)

your point about cornering is a good one; at a certain point the characteristics of a tire change and this would come out in cornering, so there is a balance. my testing was centered around a hill climb/time trial, so that wasn't so much a factor.

as noted before,

re: the last point (tubulars @ higher pressure than clinchers), i know that sounds right, but two things come to mind:
1) my testing was done on tubulars, and the tubulars had lower Crr for lower pressures.
2) tubulars resist pinch flats better. higher pressure is a way to also reduce pinch flats (for clinchers). tubulars don't need to rely on that.

for similar construction, tubular sidewalls are more supple for the same pressure (better handling)...but this doesn't mean it's got lower rolling resistance. it's really the opposite of conventional thinking.

it's part of the reason why we can run lower pressures for tubulars in CX than we can if we were running tubes or tubeless. pinching/burping a tire (for tubes or tubeless) is more an issue at lower pressure. [of course for tubeless, the sidewall is structural and therefore stiffer, so there's always a difference in feel for a given pressure. this is particularly notable for MTB tubular vs tubeless.]

i appreciate the points in your post.

we're not even getting into differing construction of tires...