I originally posted this in the new Wheel and Tire Tech board but that board seems dead, so trying here.

I know this was posted before but i cant find a thread with the info I need. I have the stock premium GT 18" wheels on my 12 GT, and its time to buy new tires. I'd like to start tracking my car later this fall and looking to get just a little more meat out back. The stock tires are 235/50/18 and i was wondering if there is a 255 I can get on there comfortably (255/45/18 maybe?)? If so what sidewall size, and is this a good idea?
Thanks folks.

 

The 255/45/18 will fit fine on the 8" wide wheel and is close enough to the oem tire height so your speedometer will not be off.

 

^^^ Correct. I've even put 275's on 8" rims, but that's really a bit too much for a car that's going to be tracked. 255's will be just fine.

 

Awesome, going to order some now. Going with some Sumitomos! Thanks a million guys.

 

I think I would ask your question to the tire manufacturer you plan to use. The reason I say that is that a tire that is "too wide" for a wheel will cause a very "sloppy feel" in the steering on a road track
http://blog.tirerack.com/blog/letter...me-of-the-time

When I recently upgraded to Michelin Pilot Super Sports, 245/45/18 was the biggest tire they recommended on an 18" wheel. If you were just buying for "street use," might not matter. High speed cornering on a road track really stresses the tires and shows up any "misfit" issues.

 

255-45s Fit awesome!
Slightly (.3inches) shorter but like (3/4inches) wider.
I love them. Give them a More muscle look.
I have Bridgestone Potenza RE760 Sports.

 

Changed tire sizes on R18s
Changed from the stock Pirelli to Bridgestone RE970AS Pole Position
245/45/R18

Tires and size provide buch better grip and firmer ride.
No comparason to the stock tires.
Really like this change.

 

Each tire manufacturer has their own wheel width recommendations, but the 255/45/18 sumitomos should be just fine on an 8" wide wheel.

 

What kind of 275 were you putting on an 8" rim?






Most tire manufacturers recommend the 9" as the smallest rim to put that wide of a tire on unless it's a monster sized high sidewall drag racing tire. For low profile street tires though it could be quite dangerous, and it is definitely beyond any manufacturers recommendations.