Re: Need help with wheel size and back spacing?
The reason why we all tell you to proceed with caution is because these cars are lmost 40 years old and who knows what they have been through. Some of the things that can cause clearence problems are both sides not equal to start with (production tolerences were not as tight then as they are now), replacement panels with repro parts or not installed perfect, sagged or rotted bushings, disc brake kits pushing the wheels out, and not all tire sizes are created equal. As far as 17s or 18s go the backspacing doesn't change because the side wall aspect ratio goes down and overall tire height stays near the same. The 8" front wheels use 4.75" backspace and the rear 9.5" wheels use 5.5" backspace. You will find some cars have deviated slightly from that usually no more than an additional .25" backspace. You will also see that some cars have dropped down to a 255 rear tire because the owner did not want to tolerate any rubbing or the car ride height is very low (3" drop or more). You will also see that 2" or 3" dropped springs will not yeild the same results on all cars. That should really confuse you now. The point is not all cars measure exactly the same and the answers we give you are proven to work in almost all cases. Thats why you will also see posts where people have fit 10" wide wheels with 285 tires in the rear. In most cases they have rolled or trimmed the wheel lips and beaten the inner wheelwell in. I think that's why this question gets beat to death. Everone sees what has worked but when you're spending the kind of money you are for wheels/tires you want to be sure. That's why we say to measure every car. The best situation is to test fit someone else's or something close to get an idea.
Last edited by JV69z/28rs; Dec 26th, 06 at 05:43 PM.