[Lemonsqr]

Which would you go with and why? Car will not be autocrossed or tracked, just occasional spirited driving when road conditions are OK.

Its only half an inch, but would there be that much performance difference?

 

[lab rat]

If you are planning on running 225 or 235 it doesn't matter. On the 8.5 rim you can run up to 255.
If the offset is the same I would pick 8.5 to make it look more aggressive. If the 8.5 has 6mm higher offset then it doesn't matter but I would still get 8.5.

 

[be-doubleyou]

I run 18x8.5's because it gives me the versatility of running anywhere from 225's to 255's. 225 on and 8.5 isnt very stretched at all. I run 255's square for DD/spirited driving and am very happy with it.

 

[Solidjake]

I would get 8.5 all around with 235 tires, good for rotating them as well.

 

[Speed Density]

I run 18x8.5's because it gives me the versatility of running anywhere from 225's to 255's. 225 on and 8.5 isnt very stretched at all. I run 255's square for DD/spirited driving and am very happy with it.

What offset?

 

[nix330ci]

i take it square means all the way around? im looking into getting a different style wheel, all the same size, so i can rotate, as i put 150 miles a day on my car, I'm just not too familar with the wheel / tire science..

 

[Speed Density]

Squarred does indeed mean the same wheel size all the way around.

 

[Snik]

8.5... 8" wide is tho thin, not enough rubber for our cars.
ypu could even got 9s.