What are the options for legal Non OEM 17x7" rims for G-stock class SCCA autocross events????

Would Kosei K1 TS be legal?
Size Selected: 17x7
Price: $199 (each)
Estimated Availability: Low Stock
Recommended Tire Size: 205/45-17
Wheel Offset: +42mm
** Lightweight: 14.1 lbs. **

And what options for competitive tires would there be to fit 17x7" rims?
What size tires?

Are wheel studs legal for G-stock??

 

Wheels studs are legal. Wheels have to be the same diameter and width as an available stock wheel, so you have to find out if any of the factory MINI rims are 17" X 7". Offset has to be the same as stock, +/- about 6mm (1/4"). Spacers are legal (if you need them) to get the offset within allowable specs.

You can run street tires or DOT-legal R-compound tires in G-Stock. I know the Falken RT615's are popular for street tires, and I think there are some R-compounds that will fit. Probably not the ever-popular Kumho V710, though - I think the narrowest 17" V710 is a 245/45, and I think you'd have rubbing problems going that wide.

Even though the "recommended" tire width you posted from Tirerack is 205mm, a 7" rim could handle 215mm or 225mm with no problems.

 

OK, but looking at the Kosei K1 TS with offset of +42mm.
Do you think spacers can be used here to move the wheel to a more legal offset? Or is +42mm close enough (no spacer needed) to the stock +50mm to be deemed legal for SCCA autocross G-stock? I know that if it was +45mm it would be OK.

Anyone try 225/45-17 tires on a G-stock car and get any rubbing?
That size seems workable.

Otherwise 215/40-17 seems OK for a 17x7" rim.

 

I just looked up the stock R90 wheels on wheelspecs.com, and that site lists them as being 17" x 7", with a 48mm offset, so the width of the Koseis you're looking at is fine, and you're within 6mm on the offset, so you shouldn't need spacers to be legal. As far as the offset goes, you don't have to be with 1/4" of the stock wheels that came on YOUR particular car, as long as you're close enough to a stock wheel that COULD have come on your car.

I don't have any experience with 225/45-17 tires, so I can't help there.

 

The R90's (ET48) are accessory wheels.

The R85's (ET50) are the stock 17" wheel.

However, the "stock" 17" wheels on the cabrio, the R91's are ET48, as are the 17" "Checkmate Horseshoe" style wheels (ET48), and the web-spokes R98 (ET48).

So it would seem like ET42 would be acceptable without spacers.

 

If you ordered the R90's with your car, when would they have been installed on the car? My (possibly mistaken) understanding was that if a part was installed at the factory or at the distro center, then it was "stock", but if it wasn't added until the car reached the dealer, then it was an "accessory". I think this is why the G-stock MINIs at Nationals still had the big honkin' cupholders in them - even though they weren't added until the cars reached the distro centers, they were considered "stock" and couldn't be removed.

Regardless, it sounds like the 17" x 7" with an offset of 42mm should be legal without spacers.

 

My understanding is the R90's are dealer installed.

My R90's were at least (back in 2002). I'm not absolutely positive that that remains the only way to get them installed though.

 

Aren't spacers used to increase the offset? If the aftermarket rim has an offset of ET58, which would move the center of the contact patch further under the car. You could use a spacer to move the contact patch out to a normal position.

With an ET35 the contact patch would be further out already and spacers would only push it even further out. See this Tire Rack article:
http://www.tirerack.com/wheels/tech/...jsp?techid=101

The larger the ET number the closer the hub is to the outside edge of the rim. So with large ET numbers a spacer can be used to reduce that figure to the stock range. But, if you have an ET number that is already lower than a stock number, spacers can not correct it.

 

Ok, this is what I thought. So if you have a wheel with greater than +48mm offset like +55 offset and you wanted to use spacers then you could which moves the wheel slightly more outwards.

But with a rim less than +48mm offset then if you can stay about 6mm from this then you can use the wheel with no spacer and it's OK for stock autocross.

So for +42 or +45mm offset in a 17x7 rim it's OK for G-stock.

In my region R90 wheels are not factory installed, they are a dealer option.

However the only time I know that R90s were factory installed was with the special MC40 limited edition MINIs. I guess those would be G-stock and be able to use the R90 wheels.

Thanks all the information helps. I still think that the biggest disadvantage is the tire selection for 17x7 isn't the greatest.

Competition tires are much better in 16" or even 15" sizes.

 

Sometimes, the SCCA will allow you to switch wheel sizes if a different spec wheel was made available on any model of your car in any year. At least I think I read that somewhere. Maybe I am thinking of something else.

But you are very correct about the choices of tires 16" vs 17"

 

The rims would have to be offered as a factory option for your model/year. There is no update/backdate provision in the stock class rules.