Need help on tire size choices for new 20x8.5 & 20x10 wheels ordered - Ford Mustang Forum
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post #1 of 3 (permalink) Old 03-16-2016 Thread Starter
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Need help on tire size choices for new 20x8.5 & 20x10 wheels ordered

Hey guys I need some help deciding what size tires I can run on some wheels I ordered yesterday. I ordered some 20" FR500's from American Muscle and took advantage of the St. Patricks day sale they are having. Ive only replaced tires before, and have never had to order new ones.
What will look and perform good on my 2011 GT?
Ive seen it where the front and the back just dont match and look funny together, I guess because of the sidewall height?? I know nothing about tires sizing I wont kid anyone.
Can you guys recommend some sizes for me. I cant break the bank. I was lucky enough to get the wife to let me order these in the first place.

I would like the rear to fill the fenderwells if possible, but its not a must.
Thanks I appreciate the help

2011 Race Red GT

Just an old married guy (with kids) and two expensive hobbies...
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post #2 of 3 (permalink) Old 03-16-2016
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An easy place to start, is look at the tires that American Muscle sells with those wheels as a wheel/tire package.

Generally, you want to match the overall diameter of your original tires, so the speedometer will be correct / won't need to be corrected. With 20" wheels, that means you will have a very low sidewall. Usually American Muscle has this all figured out, so that's why I say they are a good place to start. Also look around for the on-line tire size calculators; they are posted in some of the threads on here but I don't know exactly where off the top of my head.

| 2010 GT coupe | Daily Driver with some Steeda and GT500 take-off stuff for the occasional track day
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post #3 of 3 (permalink) Old 03-16-2016
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With the front 8.5" wheel you can't go too wide. I'm guessing a 255/40/20 may be as far as you can go. The rear at 10" you will be able to run at least a 295/35/20. As JBert has suggested, AM must have a wheel/tire package that you can refer to.


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