If I want to compete in time trials as Showroom Stock, then I have to adhere to the following:

1) Any type wheel may be used provided wheel size (width and diameter) remain stock. Wheel offset may be +/- 5mm from stock. Sounds like OEM might be my only option here, I don't know of any 16 x 7.5 rims out there...

2) Wheel spacers are not allowed

3) Tires shall be of "as delivered" construction, DOT approved with no undertread showing (for safety reasons), and either be listed in THE TIRE GUIDE or be available in three or more rim diameters.

4) Any size tire that fits on the stock rim is allowed provided it meets the following:
a) The tread fints within the stock fender and wheel well (without modification) as measured by a vertical line dropped down from the fender lip while the car is at rest on level ground with the wheels pointing straight ahead.
b) The rim width used is among the rim widths recommended by the tire manufacturer for that particular tire size.

THAT BEING SAID:

If I'm "stuck" with OEM wheels, then I could go with what sizes are already on my wheels, which are 205/55 and 225/50 BUT I understand that 245/50 might give me a bit more patch in the back.

COMMENTS APPRECIATED!!!!

Thanks

 

I believe you can go with JDM 6-spoke rims (much lighter) and Hoosier tires, 225 and 245. However, with that tire setup, most people replace the stock front sway bar with a bigger one, so to neutralize the handling a bit.

 

As has been stated in other threads,
the rear 225 S02 Potenza for the S2K
is the same width as a 245
in any other brand or model of tire.
I compared an old 245/45-16 A032R
on an NSX rim to the stock rears and they
are the same width.

MG