IT Wheel rules change?

[bobc_5]

I'm building an ITA Miata (stock 14 inch wheels), I just came across the rules on wheels and found the following:

7. Wheels/Tires
a. Any wheel/tire may be used within the following
limitations:
1. Cars originally equipped with twelve (12) inch wheels
may fit thirteen (13) inch wheels. Cars originally
equipped with metric 365 wheels may fit fourteen (14)
inch wheels, and cars originally equipped with metric
390 wheels may fit fifteen (15) inch wheels. The abovementioned
cars as well as those cars originally equipped
with thirteen (13) inch or fourteen (14) inch wheels
may fit up to a fifteen (15) inch wheel. Cars may not
fit wheel diameters smaller than those listed on their
spec line. All other cars shall retain the wheel diameter

Does this mean I can run a 15 inch wheel? I fear I'm missing something obvious.

Thanks for any input.

[lateapex911]

Yes, you may. But...it's not always better to run 15" wheels. Give some thought to the trade offs in ride height, circumfrence, available wheels, availble tire sizes, gearing,weight of tires and weight of wheels before you decide.

[JimLill]

be to explore what tires sizes are available in what types and compounds.

[Andy Bettencourt]

15x7 on a Miata are great. That is what I have had sucess with - that and the 205/50/15 Goodyear RS.

[bobc_5]

Thanks for the information!

[tom_sprecher]

What about on a 1st gen RX-7 running IT7? What tire does SM run? If it would happen to be the Toyo Proxes in 14" it would open up the possibility of some serious tire pile diving at the nationals.

[MMiskoe]

15x7 on a Miata are great. That is what I have had sucess with - that and the 205/50/15 Goodyear RS.[/b]

Have you ever run a 225 width? Thoughts?

[Andy Bettencourt]

The 205/50 RS is as wide (or wider) than the 225/50 GSCS. No room for more tire. Besides, at 2400lbs, that may be too much tire. Somebody at Goodyear went to the "Hoosier" school of tire width measurment...