Hi, I'm looking at buying some 18 x 7.5 rims and I'm not sure what size tire to use on them. I know that it needs to be X / X / 18 for the rim diameter, but which measurement on the tire shows whether or not it will be appropriate for the 7.5" rim width?

The current tires on my car are 235/55/17's (the current rims are 17 x 8), and I'm okay with how those fit in the wheel well relative to the empty space aorund them, so I'm not sure which tires I should be looking for to fit an 18" rim that's only 7.5" wide.

 

what is the year and model of your car?

 

It's a 2006 v6 Mustang.

I saw quite a few options at TireRack.com for 255/45/18's which I think would be okay, I just wasn't sure that those would mount well on a rim that's only 7.5" wide, given that Ford's stock rims for the 06 Mustangs are 8" wide.

 

The sizes we recommend for your car are 235/50-18 or 245/50-18. Both would mount fine on a 7.5"
rim. 255/45-18 would need at least an 8" rim.

 

Awesome, thanks for your help Colin!

 

i have a 98 GT that has been lowered but i don't know exactly how much it appears to be 1.5 in. lower than astockGTand has cobra 17's wraped with 245/40/17 with about a 1.5 in. gap between the tire and fender can you guess about how much it has been lowered? and will a 275/4/17 street slick fit under the back?