I'm running 15x8 with a 35x12.5 tire. off-road I can air down into single digits and not worry about that tire coming off. the off-road footprint is insanely large, so traction is superb. another plus is tire pressure for street is very forgiving. I've run my street pressure as low as 22 and as high as 30. same wear pattern.
this is tied into it's downfall. crowning. you can't get rid of it. the wear patter appears like you're running with too much air, no matter the psi. seriously, and others running this setup will back me up, its really not bad. it's a small price to pay having 15x8's on 35's. factor in all the benefits of 15" rims, then it only being 8" wide..you'll see what I mean. 35's, nor 15" rims are ment for street queens. the combination of 35x12.5 on 15x8's CAN'T be matched off-road