Gen 1 rear tire rubbing

[defilade]

Has anyone had issues with rear tires rubbing the inner wheel wells on a Gen 1 with 15x9" wheels and 275/60 tires?

What's the normal clearance between the tire and the inner wheel well at the front (leading) edge of the tire?

Background: I recently bought a Gen 1 coupe and the tires were old (2008) so I ordered new tires in the same size and model - Mickey Thompson Sportsman S/T 245/60-15 front and 275/60-15 rear. Wheels are the FFR repro bolt-ons, 15x8 front, 15x9 rear. The car was built from a complete kit with IRS so it has coilovers and the Ford 8.8" rear end. It has 6500 miles on it and came with the original tires from when it was built in 2009-2012.

When we took the rear wheels off, both inner wheel wells had minor rub marks. The rubbing did not look severe and the old tires didn't show any obvious damage from rubbing either. We briefly put them back on to check the tires' clearance from inner panel and it was very tight, a bit less than 1/2". I could barely get my finger tips in that space.

After installing the new tires, the left rear is rubbing during normal driving. I could hear it right away when coasting to a stop - it doesn't rub all the way around the tire but in one area. And the clearance from the inner panel is even less than with the old tires. Since they're the same brand and size of tire, I'm guessing the manufacturer may have changed the molds over the years and the new ones are a bit wider.

I did talk to the original owner/builder, Chris Bergquist, and he did not recall having any issues with the original tires.

Thoughts?

Pic of left rear wheel well

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[David Williamson]

My car is a Gen 3 so different from yours and it runs much wider tires on 18 inch wheels with lots of space.
check the rear tires are on the correct wheels? shops can mix them up. Maybe add a small spacer 1/4 inch? I assume there is space on the outside to the fender.
David W

[defilade]

My car is a Gen 3 so different from yours and it runs much wider tires on 18 inch wheels with lots of space.
check the rear tires are on the correct wheels? shops can mix them up. Maybe add a small spacer 1/4 inch? I assume there is space on the outside to the fender.
David W

Thank you for the suggestions. The wheels and tires are correct. It seems odd to me that it would have been designed with so little clearance, but what do I know.

I ordered a set of BFGs for the rear to see if they're built a little narrower. Spacers are a good suggestion, but unfortunately the studs are not long enough to accommodate spacers and changing them out for longer ones is a bigger project. So we'll start with different tires and see how it goes.

[David Williamson]

Good luck and don't be afraid to reach out to people here for help. If you tell us your location there are probably people near you that would be willing to go to your place and help you out.
as I am sure you know all these cars are custom and each one is different.
David W

[defilade]

For the benefit of others...we added 1" bolt-on spacers on the rear. I don't know if spacers were included in the Gen 1 kit but my car was built without them. The real issue was that 15" wheels don't clear Mustang brakes by more than a few mm without spacers, so the brakes were actually starting to touch the wheels (just barely). With the 1" spacers, the tires are pushed out enough that you can't run 275/60 tires. So I'm using shorter tires for now until I decide on a different wheel package.

[turbodon]

I can tell you all that aluminum does not come with a Gen 1 Coupe. The Gen 1 only has a rear aluminum panel in rear of fender. Nothing around IRS. You could see the inner square tubing as well. So get a big hammer and beat it in a little.

[defilade]

I can tell you all that aluminum does not come with a Gen 1 Coupe. The Gen 1 only has a rear aluminum panel in rear of fender. Nothing around IRS. You could see the inner square tubing as well. So get a big hammer and beat it in a little.

turbodon that makes sense - but the real issue was the brakes hitting the wheels. So we had to add spacers anyway, and that solved the problem.