car has a pair of 255-60-15 on the rear that rub on corners and bumps(RR is the only one that seems to rub)The wheels are 7 inch ralleys with 4 1/4 inch backspace. my first inclination was to get two smaller tires, but I have a matched set of firestone firehawks that are still like new. If I find two ralley rims for the rear with say 4 1/2 or 4 3/4 backspacing will this cure my problem. Can anybody tell me what cars came with more backspacing? thanx wnk.
I'm not aware of any original-appearing 15x7 rally wheels with more backspacing than you've already got.
Because the rub is happening on just one side, I would crawl underneath with a tape measure and check how much space you've got between the tire and the inner fender-well on both sides in the back. If the dimensions from the right side and the left side of the car are quite a bit different, then maybe your differential is sitting further over towards the right side and causing the rub.