Solo Rules for stock class section:

13.4 WHEELS
Any type wheel may be used provided it complies with the following: it
is the same width and diameter as standard, and as installed (including
wheel spacers if applicable) it does not have an offset more than
+/- 0.25 inch from a standard wheel for the car. The resultant change in
track dimensions is allowed.

So for Mustangs equipped with 19 inch rims can they be changed for 18 inch rims of same width?

Here is the dilemma - '12 Boss 302 is equipped with 19x9 front and 19x9.5 rear rims.

18x9 rims are an option on '12 Mustang GT, but you can't order a Boss with 18 inch rims? by "standard wheel for the car" does it mean Mustangs in general or specific option packages?

Reason for question; Hoosier only has a 9.6" wide tire for 19x9, 19x9.5 rims, but has a 10.3' wide tire for an 18x9 rim. I would like to run the cheaper and wider tire on all four corners of the car.

Model specific. If the Boss wasn't optioned with it, that car cant have it unless it is converted to a regular GT in whole.

That specific wheel must be a factory option for your option package car. Was the Boss 302 offered with the 18" wheel as an available option, or only with the 19"? If you can find it as an option in the brochure, and can show that it was a factory option, you should able to make a case for it if you're ever protested.

As said above, if it is not an option for THAT model car, than NO. The Boss 302 is a model, so the question is on what model Mustang do you want to change wheels?

I thought that might be the case, seems I really screwed up by buying a Boss thinking it was a cool car.

So now its in a class where it cannot be competitive (A-stock?) and I have to run narrower tires because it was not available with 18 inch rims.

Dang did I waste a bunch of money....but the car is still cool.

I'm confused... what's wrong with Hoosier 265/35/19 fronts & 295/30/19 Rears?

Seems like those would work fine on the OEM wheel sizes.

Or just run the 295's all around...that's what I'd do.

In any case, get that car out and run it! Based on current AS times, it should be right in the mix and it is guaranteed to be fun.

ItemNumber Tire Size TreadPattern TreadWidth Approx.Dia Circ Recom.Rim MeasuredRim * SectionWidth
46925 P265/35ZR19 E 9.6" 26.2" 82.25" 9-10" 9.0" 10.4"
46935 P295/30ZR19 E 10.4" 26.1" 82.1" 10-12" 10.0" 11.5"

295's not recommended for 9.5" rim? or you think it will be ok?

Definitely be ok... it's what 'live axle' was made for. :) You can try the 265's all the way around... but to put it in perspective... all the Mach 1 mustang guys of 2003 2004 model years... ran 275/40's on 8" wheels!

Enjoy the beast!

Dave

I run Hoosier 295/30R18s on 8" wheels. The recommended rim width is just that -- a recommendation.

Thanks for the Help, I will run the 295's all around. And yes I will enjoy it.