Wheel/tire fitment question

[Avispa]

Did a lot of searching on the forum and haven't found clear answers yet....

Time for MUCH bigger back tires. Have 275/40/19s on stock GT/CS wheels on the back. Looking at Carroll Shelby CS-14s in 20x11 for the back, 20x9.5 up front. 7.97/6.80 r/f offset. Tire calculator says 325/30/20 are almost identical diameter to the 275s on the back. 255/35/20s up front are a good diameter match. For the 255/40/19s up front.

Are these gonna fit or am I going to need spacers? I can't find the backspace specs on the stock wheels. The 11s out back seem to be enough, but I'm open to other opinions.

If you want to suggest different wheels, I'm a chrome age guy. All black is not gonna happen. Some bright metal is a must. I like the ones I have, but they don't make 11s for the back.

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[rxryanm]

7.97/6.80 r/f offset

I think you already know this based off mentioning backspacing for stock wheels, but that's not offset. Offset for those wheels are 30f/55r.

I have PP1 wheels with spacers and the Shelby wheels stock are pretty close fitment-wise to what I have, which is flush/slight poke. Rear tire will have some bulge, but should be fine if you aren't lowered.

 

[Avispa]

Ryan:

Thanks very much for the comments, and yeah, I meant backspacing on the wheels rather than offset. I can deal with a slight poke; the car isn't lowered. The concern was more with tire interference on the inside.

Previous experience with oversize rear wheels was with aftermarket 17x10.5s on the back of my last Terminator. Those were a tight fit, and for safety needed a button/Allen head bolt to replace the factory hex head upper front subframe mount bolt.

 

[EFI]

Are these gonna fit or am I going to need spacers? I can't find the backspace specs on the stock wheels. The 11s out back seem to be enough, but I'm open to other opinions.

19x11 +50 with 325s fit nicely. They poke out just a tad bit at static OEM height (will probably tuck on a hard launch or lowered), but there is plenty of room inwards. So a +54-56 offset would be perfect.

 

[Avispa]

EFI, thanks. That's a huge help. With the 275/40s out back, the tires just spin like a top when the throttle decides to kick in, which isn't always predictable. That's a story for another thread....lol

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