now don't go all mathematical on me. i know if we're talking miles an inch isn't much and when dealing in mouse holes, it's a big deal. i mounted my 7.50-16 firestone deluxe champions on a 16x4 inch wide wheel and it all came out ok. i'm going to reverse these 15x6 inch ford wheels and mount some 15x8.20 firestone dragster cheater slicks on them. all the web stuff calls for a minimum 7 inch wide wheel. think i'll be ok?