What is the biggest size tire that I can put on my mustang? Right now I have 255/40/17 in the front and 275/40/17 in the back. I wanna keep the 17's but can I get a bigger tire?

 

I know you can fit a 315 or 335 in the rear on a 9inch wide rim...but I don't know if they will squeeze on the stock GT rims. Widest you can really go in the front is a 275...even then you will have some rubbing issues close to lock.

 

On the stock 17" rims I wouldnt go bigger than a 275. I have some 315/35/17 on mine but they are on a 10.5" wide rim.

 

look at the tire specs on tirerack. Most manufactures list a recommended rim width as well as acceptable rim widths for each size of tire.

 

The rims that I am using are HRE Performance 17x9's

 

What you can make fit and what will fit safely are two different things.