Hello everyone,

Please forgive me if this question was asked previously, as I am still fairly new to this site.

I have a 2014 Mustang GT/CS with 245/40/19 tires and was wondering what would be the widest I could go on the rear without causing any negative performance issues. I would like to take it up to 265 but not quite sure. I think its a 19x8.5 rim.

Thanks very much,
Rick

 

The tire manufacturers usually have the suggested rim width on their websites for all of their tire sizes. That being said they usually seem to leave some room as well. In my opinion, a 265 would be fine, but there are others on here that are much more knowledgeable on the subject that can hopefully help out.

NT555 Summer Ultra High Performance Tire

 

Your stock tires (assuming that's what you still have), are 245/45R19, not 245/40. The Brembo package cars had 255/40R19 on 9" wheels. You can put 275/40R19 on your stock wheels, they will fit and work OK, but that rim width is 1/2" narrower than recommended by most tire manufacturers. 275/40 will match the overall diameter of the 245/45 OEM tires. Unless you are taking the car on a road course and tracking it hard, the 275 won't be an issue for you.


cheers
Ed

 

Thanks Chad.

 

Thanks Ed. I think you are right....stock tires are 245/45/19. I was at a tire & wheel shop on the weekend and they did not recommend going higher than 255 on my wheel size unless I go with a wider wheel in the rear. I really don't want to change the wheels so I will have to give it some more thought.
No plans to track the car just yet, however, you never know. Lol.

 

If you have stock CS rims then they are 19x9.5. 265 wont be a issue

 

Thanks Milner. They are definitely stock CS rims (black machined aluminum 5 spoke). I can't seem to find the actual specs from Ford, but when googled, most reviews say they are 19x8.5.

 

X2 what Ed Said.

 

Incorrect ... they are 8.5". The Brembo pack wheels are 9", and Boss 302 were staggered 9.0 / 9.5". The only S197 with factory 9.5" all around were the GT-500.


cheers
Ed

 

I stand corrected