Need help with tire selection

[antbanks2286]

Hi everyone I am new to the forums and I have a quick question. I have an 07 grand prix gxp that has 255/45/R18 tires in the front and 225/50/R18 tires on the back. My question is if it is possible to get 255's on the back as well, and what it does performance wise? Thanks!

 

[QwikGT]

i wouldnt, the car needs the wider wheels in the front to combat the V8. i say leave it as is. i run 255/50/16 in the front and 225/60/17 rear.

 

[Panther427]

You cant fit a 255 on the back because the wheels are differant width. Fronts are 18 by 8 inch. The rears are 18 by 7 inch. I think the most u could squeeze onto the 7inch rim is a 245. But that is reality u would wanna go over a 235. having a 245 changes the loading of the tire in relation to the rim and can cause premature wear even blowouts. But there is a clearance issue with the tire and the rear shock of going this wide in the rear. You could put a spacer on the rear to make more room but then your rear wheel would stick out more and personally i think it would be unatractive. I have been thinking this over in my head for some time. personally i live in a snow state. And as im sure you have found out there is truely a limited tire options for the stock sizes. I like the handling the staggering sized tires provide. But for me im planning on running 17 by 7 and put 235.60 or 235.55 tires all they way around. Provides extra sidwall for the ruff winter roads and tires are alot cheaper. When i replace the stock tires i will be choosing Nokian tires. They are harder to find in the states. But i have run therm on other cars and they are great. They even offer a great all season with sizes that are close to stock. I think lik 245/45/18s

 

[Panther427]

Also some companys say 255 will apear wider than others even though they say are the same width.