I just bought this Grand Prix SJ and was woundering what is the widest
On a 14-inch rim I would not go beyond a P225R70, step up to a 15-inch rim and you can go to a P245R-60, beyond that and you have clearance issues. A 5-spoke 17x8-inch chrome rim with P245ZR17's with 4.75-inch backspacing would look good and work just fine. I have owned two of these cars and would love to have another.
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