Originally Posted by
jimincalif
Hysteresis. Riding a smooth velodrome track or rollers, thin tires at high pressure are fast. Take them out on real roads and the rough ride translates to lots of lost energy from bouncing your body up and down. Smoothing out the ride reduces those energy losses. I run 25s on my older bike, on 23mm wide rims they measure 28 inflated. My newer bike with discs, I’m running 30s on 28.4mm rims, they measure 31.5 inflated. More comfort is an added bonus.
^this.
I need to look for the study, but some mechanical engineering professor did a study on this and proved this experimentally at the expense of grad students riding repetitously over rumble strips.