If I understand it right, backspacing refers to how far toward or away from the leaf springs the rear tires are. If I had a monstrous backspacing, say 6", on 15x8's, then the rim and tire would probably hit the leaf springs, but the not hang outside the body. Is that right?
Before I knew about this website, I bought Cragar Quick Trick I wheels (15x8 back, 15x7 front), and put Hoosier 275/50/15's on the back. When it takes a decent bump, the tires rub into the wheel wells. In the future, I'll put better leafs on, and consider backspacing, but for now I'll pay more attention to bumps. Just checking. Thanks.