So I've decided on a set of rims in 18x10 (rear) and 18x9 (front). What tire size are you finding will fit best on this rim on our car?

 

why 18x9 in the front? If you go 18x10 in the rear, put 285/40's on it. They will be 27" in diameter so your speedo won't change. I put 18x8 on the front with 255/45's. They were also 27" in diameter. Stock tires are 27.2" in diameter.

Edit: Perhaps this should be moved to Exterior mods. It really has nothing to do with performance for the GT since these rims will also fit on a V6. There are a lot of tire threads under the exterior mods that you may want to do a search on.

 

I have a choice of 18x10 or 18x9 in the front. I don't see the point of 18x10 all around so I might as well save the weight/cost of the larger rim/tire from the front.

This can be moved if you would like, but I see this as a necessary "performance increase" for a GT with more power than stock, like, oh, say a supercharger?

 

Check sig. for the setup i'm going with.

 

check out the Roush - 18 x 10's on each corner with 275 X 40/ 18"s. looks goooooood! Also - check out tire rack's web site - good data wrt manufacture's recommended rim width by each tire size.

 

I'll have to agree with that

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No reason not to put 18x10 on all 4 corners w/ the 275/40's. U could rotate...same side that is w/ the comp tires.
I love it, handles great.
SS-