I am looking for new shoes for my new ride (when i get it ) I am just curious as to what size will fit? I will have a 1999 mustang automatic. I am looking at the 18's with the car lowered about an inch, what width can i go up to with those without having to do any modifications to anything?

 

hard to tell that without the wheel width

 

Tirerack recommends 245/40/18s on 18x9 rims. Optionally, you could run 275/35/18s on 18x10s on the rear.

 

thanks, I was looking at the 275/35/18 for the rears and the 245/40/18 for the front, and i was hoping that they would work. thanks for all the info. B)

 

wont be able to rotate your tires. and my cobra rims are 9" and i can put 315 's on them

 

You don't specifically say what size you're using front and rear, but if you're running 18X9's all around, then go with 275/35/18 tires all around. I just put these on my new 18X9 white Saleen wheels, and haven't experienced any rubbing problems yet with a similar drop on my car as you described on yours. If you do get some rubbing (which some have reported on another forum site), then have steering rack limiters installed on your car. Saleen and Roush use them on their cars. They're cheap, and easy to install, but chances are, you won't need them. You can fit 245/40/18's on 18X9 rims, but it will be more difficult to seat the tires to the rims, and it won't have as aggressive a look. Trust me, 275/35's are your friend!

If you're running 18X10's in the rear with 18X9's in the front, try to stay with tires with the same profile ratio (35's), otherwise, the front and rear won't look balanced. Go with 315/35's in the rear for 10" rims.

Tirerack.com is a good web site, but their recommendations are based strictly on the closest oversized tire match to stock relative to revolutions per mile, not how well they will fit the rims or looks. If you're concerned about your speedo accuracy, check out http://www.miata.net/garage/tirecalc.html It's a great resource!

 

Thanks Pony Ride, that tire calculator is awesome! I have decided to take your advice and go with the 275/35/18, I think that will look great. I have also decided to go with the Steeda Ultra Lite Satin II wheels. Thanks to everyone for all the help!

 

consider upgrading your brakes. when you go from 15-16 to 18, thats a whole lot more 'rolling resistance'. Your stopping distance will go up, so make sure to take some time to get used to it.