I have Kumho Venture King MT's (31-10.50x15) on stock alloy rims on my 89 4dr, and they never rubbed no matter how much I flexed it, and I weighed in at 5275lbs with a full tank and a big load of stuff on the landfill scales, and I wheel it the same way, plus some wheeling only stuff that's probably another hundred or so. I have no lift and no torsion bar crank, and I've got my caster set as close to zero as I could get it.

The bumber end caps are the very back trailing edge (is back trailing edge redundant?) sharp edged rubber stuff on the end of the front bumber, the part that reaches to the edge and a little of the wheelwell, outside the body. I chained my bumper ends to a tree and backed up the truck in 4wdlo to straighten up the classis Monty shoved back bumper ends syndrome. Combined with whanging the two ripples in the bumper steel channel just outboard of the center bumper guards with a 4lb deadblow hammer, I got my whole bumper ends back parallel with the body where they are supposed to be. I'm not sure if that's why it never rubbed, because I did it before I bought the tires. It came with whoozat thirtyonetenfiftyfifteen A/T's about 70% worn and round shouldered, and the Kumhos were noticeably wider and edge knobbier and square-er, in a round kind of way....