What size tire for these rims

On 17x8 you can do 245/45R17, like stock '94-'04 Mustang GT size, or 255/40R17 or 255/45R17 or 265/40R17.

On a 17x9, don't do less than 255 or more then 275. Anything less looks too skinny for the wheel and anything more looks too big for the wheel.
 
:scratch: about those numbers, just was on SVT site and looking at the replacement for the lightning, says it has 21x9 rims, that having been said, they also have a 295/45 on that, which leads me to believe that a 295 can fit on a 9 inch wheel, just seems kinda backwards from what ive heard/seen.
 
J_Squared said:
:scratch: about those numbers, just was on SVT site and looking at the replacement for the lightning, says it has 21x9 rims, that having been said, they also have a 295/45 on that, which leads me to believe that a 295 can fit on a 9 inch wheel, just seems kinda backwards from what ive heard/seen.


Tire measurements don't work like that. They aren't just what you see. I wish I was awake enough to try to explain it correctly...but it is too late anyways :bang: It's all about the combo of tire sizes.

The SVT's 99-03's Lightnings are 18in. wheels I believe.

I have seen 285's on stock 17x8 wheels. Not cool...look too wide and don't handle very well.
 
Here's a basic rule of thumb. If you divide the tire width by 25.4 it converts to inches.

295/25.4 = 11.61 inches

Now if you take a wheel width and add 1 inch to it you get it's true wheel lip to wheel lip measurment (approximately). On the lighening that would be 9.5+1 = 10.5

So the difference between the tire width and the wheel width in this exampleis barely more than 1 inch. Any difference up to around 1.75" (give or take) is ok.

But you gotta look at sidewall as well. A 275/50R15 has about 5.5" of sidewall, while a 275/40R17 has about 4.3" of sidewall. The shorter sidewall is less tolerant of excessive sidewall buldge.