Rim and tire back spacing

So I purchased a 1989 GT that has been lowered and has been converted to a 5 lug using axles and spindles from a SN95. The front has 13 inch brakes with a dual piston calipers. The back axle is a stock 8.8 with a disc brake upgrade and axles that are 3/4 inch wider (longer)on each side.

It currently has SVE Saleen style 18 X 9 inch rims with a 6 inch back space that I've removed to sell. I'm also removing the lowering springs too include struts and going back to a normal ride height and adding a drag pack tire set up.

For the front I know I need a 17 inch rim to clear the bigger rotors. However, I plan to run a 15 inch back rim with ET Street Bias tires. My question is regarding what size rim and tire setup to use keeping the back spacing in mind. I was thinking a 15 x 8 with a 6.250 back spacing, but I cant find anything that fits that specification.

Any input on those running a similar setup? I'm trying to avoid purchasing what wont work.

Thanks for any help!

I have a badass set of belaks for a fox. Text me ill send pics and ship them.

412 651 1920

Anybody out there with the same issues?


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I'm looking at a Drag setup to put on the car. The front will be a 17 inch rim and a 26' tall tire. I was considering a 15x10 with a Mickey Thompson 26x10.5 on the back.

Anyone here ran a similar setup? I also looked at the 17x9.5. The 5 lug 3/4 longer axles and bigger rear disc brakes are definitely a hang up when trying to purchase a rim and tire that will fit a Foxbody.

You will need more like a 7.25 backspacing for the SN95 rear axle length and a 15x10 rim with a 10" tire. Fox length works best with a 6 5" backspace.

Also keep in mind rear coilovers in the stock location often have less tire clearance than the coil spring.

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Which rear convsersion is out back? The solid 10.5" rotors from a GT, or the vented 11.65" rotors from a cobra? A 15" wheel may not clear the cobra setup....in fact I am almost certain most won't.

If you want to spend some money you can change some parts and go back to the standard fox width. It will pull the axles back in that 3/4" and still retain the disk brakes.

You would need a set of axles

For example
Mustang 28 Spline, 5 Lug Axles w/ 94-04 Flange (79-93)
Moser Mustang 28 Spline, 5 Lug Axles w/ 94-04 Flange (79-93) A882851SN

And a set of the correct axle brackets for your brakes
Mustang Rear Disc Brake Caliper Adapter Brackets For 94-04 Cobra Calipers (79-93)
Mustang Rear Disk Brake Caliper Adapter Brackets For 94-04 GT/V6 Calipers (79-93)

After you relocate the wheels back in....wheel selection will be MUCH better and easier for you


I've got Cobra brakes all around on my car with the wider axle out back and trying to get wider rims and tires out back is a PITA on this setup. I'm debating the above parts myself.

It does have the 3/4 longer axles and the rear brakes of a 93 Cobra. The 15 inch rear rims do hit the banjo bolt and I see they sell a low profile one.

I placed the 275/60R15 DR’s with a 10 rim off my other car on the back and they looked like they might fit if they’d clear the banjo bolt as mentioned.

I want to run a ET street but not sure if they’d be wider. If so I’d probably rub.


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93 cobra? 4-lug?

5 lug axles with 93 Cobra style brakes.


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