I have a 2007 GT California Edition with the factory 18" polished bullitt wheels (currently running 235/50zr-18"). I'm not sure but I think the wheel diameter is 8.5" (maybe someone knows for sure). I like the looks of the factory wheels. However, I want to go with wider tires without messing with the TPMS (tirerack wants $450+ to fit new ones). What tire size options do I have with the stock wheels?

Thanks!
Steve

 

255s.

 

I think George meant to say 255/45-18s

 

Yep that's the closest to the stock 235/50 - 18's diameter.

235/50 - 18 = 27.24" diameter
255/45 - 18 = 27.03" diameter
245/45 - 18 = 26.66" diameter
255/40 - 18 = 26.02" diameter

And I do belive we have the 8.5" rims and 255's will fit 8" through 10" rims IIRC. with 9" being the preferred rim width for a 255 tire.

 

Yup, 255/45R18's I checked out the BFG data page, they measure 10" overall on a 8.5" rim (the measuring rim width listed o nthe data page).

 

Your 18" wheels are 8.5" wide, so you are limited to 255 wide rubber.

 

Ouch I guess I better take my BF Goodrich KDW 265/40/18 back. But I sure do love the way they look on my Black 07 GT/CS. No sidewall budge and as soon as I get the lower springs and Tokico D-spec's on it will look sweet.

 

Thanks Guys!

 

275s will fit and is about the biggest you will want to go on the stock rims. But Ive seen people with 285s, there is a slight buldge.

 

got some pics?

255/45 is the ""recommended"" widest for 8.5.
But since when do we do whats recommened!

 

Since installing a tire that isn't designed to fit a specified rim width can lead to tire failure. While the repurcussions for the driver of the vehicle may include property damage, injury or death, the real problem is when it goes beyond the vehicle and driver and invovles the motorist around you. Fortunately such occurances are probably small (I say probably because the tire industry looks at this stuff like dancing around a frigg'n nuclear time bomb and alot of information is kept off the radar so that the money vultures and feds dont have a field day with it). None the less, if you take your vehicle to a shop and they install a tire that isn't engineered to fit a particular rim then they have opended themselves up to serious liability, if they do it and insist that you sign a waiver (which is norhing more than an admission of guilt) the waiver only covers the person which agreed to have the improper tires installed, everybody else is exempt from this waiver. Now if the tire shop has some sort of certification which is derived from procedures developed by thier tire supplier the improper installation may also involve the tire supplier if anything bad should come of it. So right there, if somebody installs the improper tire on an improper rim, the driver, the installer and the possibly the tire supplier could have to deal with the legal implications.

My advice! Do some research (the internet is okay, but highly unreliable when it comes to real and accurate information) get the engineering data from the tire manufacturer and possibly the rim manufacturer and fit the proper tire on the proper rim.

 

I agree 100%

 

And I only drive my Mustang 55mph too!!!

dly