Originally Posted by
late
"Why do Americans always want so much pressure?" I didn't have an answer.
Bigger / more is better. The American Way. Duh?
Seriously... wider tire <==> lower tire pressure is necessary to avoid pinch flats. Sheldon Brown's site has a nice table of suggested pressures given weight born by a tire and the tire's width. Obviously the rear tire has more weight on it so you can get away with a lower pressure in front but will need a higher pressure in back. There's really no reason (on most bikes) to have the same pressure in front and back. It's pretty much guaranteeing that one will be suboptimal.