I recently went through this and every car/wheel combo will be different. I have 15x4 Welds with 2.25 back spacing and a 205/75R15(27.1in. tall) hit on the front edge of the fender by just a bit. A 205/70R15(26.3in. tall) fits fine. My car is fairly low in the front with only a few inches between the under-steering headers and the ground. I have the 70's on there for now but my go back to the taller tires when I get the ride height sorted out. First pic is the 26.3's second is 27.1's