Front Rubbing - Tires, Suspension or Wheels?

Here is a shot of 255 x 45 x 18's on 8" rim with 5.5" bs on my cuda with a 4-link so no interference from leaf springs.

You can see that the back side of the tire is very close (1/4") to the inside edge of the wheel well. On the out side of the wheel well there is maybe 1/2" clearance and that's as far as I would go without risking tire rub. Any rim wider than 8" on my car rubs when I lower it. Remember that an 8" rim is really 9" wide, a 9 is 10" etc.....

This pic is with my suspension unloaded. The tops of the wheel wells are narrower so it's even tighter the lower you drop your wheel wells over your wheels.

Getting help from the tire pro's picking out what will fit your specific car will make life a lot easier.