With a 15 x 8 rim and a 3.5 back spacing you will not have any problems with a tire that is 275 wide. I have also seen 15 x 8.5 with a 4 inch back spacing no probs what so ever. Mine are 15 x 8 with the 3.5 back spacing.
Tire size in the pics 235/60/15 MT DR's Certainly no rubbing issues with those, but they're embarassingly small IMO. I'll be running 275/60's this year with alum drums and 1/4" spacer to keep them off the frame. I will have race axles with 3"x1/2" screw in studs so a small spacer will be a non-issue for me. This is the setup Grumpy ran on Melissa's car before they notched the frame.