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Wheels and TiresNeed help with wheels or tires? Got fitment issues? Have questions about tire performance and handling? Ask all of those questions here!
Oh, it's definitely more along the lines of 7 inch backspacing, not 5.5 inch.
Clearances are down to the gnats *** with tires that wide. You really just need to measure things on YOUR car to verify fitment, and then add a smidge extra backspace for safety, because you can always add a thin shim to push the tire out but you can't make it tuck if the wheel isn't deep enough.
I am running a 4th gen rear with 19X10.5 wheels with 69mm (2.71 in) offset and 8.47" backspacing. They stick out just a tickle too much. However, with a stock 3rd gen rear width they should tuck under perfectly. That's what my measurements have have yielded me and I will build my Ford 9" to the stock width. So as QWK mentioned, you're going to need 8 inches plus offset.
There are 2 different ZR1 wheel offsets, but i had the "low offset" type that required a 1.25" adapter, they were 7.4 inch backspace wheels I think. The high offset ZR1's were 7.93" backspacing, so you'd use a 2" adapter as is typical for 4th gen wheels. I'm running a stock width thirdgen 9-bolt.
So logically I think with the 1.25" adapter, they became 6.15" backspace wheels. Fit was very tight on the inside. I found I could never get them just right so that i could autocross with them without rubbing even with a bunch of rod ended tubular rear suspension pieces, but for any day to day driving they were perfectly fine and the rubbing I did get was minor and only in extreme situations, and only one one side. So I think if I kept adjusting the panhard bar I could probably have gotten it perfect. There is one caveat - I've heard Nitto's run small, and I had Nitto NT555's on mine. So if they ARE significantly narrower than the very few other options for 315/35/17's, you may want to gravitate towards those to limit your rubbing.
I dont think there's any way to get them any tighter into the car than I had them at 6.15" backspacing without tubs/minitubs, but that amount of backspace is totally possible with a BFH and stock fenders etc.
Last edited by InfernalVortex; Oct 4, 2024 at 01:27 PM.
There are 2 different ZR1 wheel offsets, but i had the "low offset" type that required a 1.25" adapter, they were 7.4 inch backspace wheels I think. The high offset ZR1's were 7.93" backspacing, so you'd use a 2" adapter as is typical for 4th gen wheels. I'm running a stock width thirdgen 9-bolt.
So logically I think with the 1.25" adapter, they became 6.15" backspace wheels. Fit was very tight on the inside. I found I could never get them just right so that i could autocross with them without rubbing even with a bunch of rod ended tubular rear suspension pieces, but for any day to day driving they were perfectly fine and the rubbing I did get was minor and only in extreme situations, and only one one side. So I think if I kept adjusting the panhard bar I could probably have gotten it perfect.
I dont think there's any way to get them any tighter into the car than I had them at 6.15" backspacing without tubs/minitubs, but that amount of backspace is totally possible with a BFH and stock fenders etc.
