[Myron Piatek]

I've always heard that a wider rim will allow a little more air pressure while maintaining a flatter footprint. More air also reduces sidewall flex a bit which would help them last longer.

A narrower rim tends to allow a tire to "grow", but that wouldn't be as much of a factor with radials since they don't grow anywhere near as much as a bias ply slick.

I saw that most stockers use 10" rims with 9" slicks, so that's what I've always run, with bias ply at first and radials ever since.