I've got the stock 17 inch wheels on my 05 GT and was looking to get new tires. The stock tires are 235/55-17. I was wondering how much bigger I can go over the 235 width without runnng into any problems on the stock wheel.

 

Go to the Tire Rack website and look at the "Spec" pages for tire makes/models that you might be considering, or which at least have the sizes that you are thinking of getting. The widest tire you should mount on your wheels is the size that lists your rim width as the narrow end of the "rim width range".

 

well my friend has a 99 mustang and he put 275s in the back with a 17 X 8.5 and it looks good and he has no problems with it ....some may say that it is pushing it but he hasnt ran into anything yet

 

255 is as far as I'd go on an 8" wheel.

 

I'm with a lot of people...255 is going to be pretty safe and decent...yeah I know some guys are getting into the 265 and even 275 range....but damn...if you corner too hard...you are running the risk of rolling the tire off the bead....and then...well let's just say...bad day!!!!

 

255 on an 8 inch wheel - anybody that says more isnt very wise