Mike96Coupe

I have a 96 LT1, 100% stock except for wheels and tires. My street tires are on larger rims than factory, 9.5x17 with 275s front, 11x17 with 315s rear. My race tires are the exact same size wheels and tires. When running in a NCCC autocross or a HPDE event am I a 1G in with my street tires and another class with the others? Thanks for any guidance.

Gman57

I belive that with other than stock size in NCCC you will be in group 2. In HPDE will make no difference since you are not competing.
G

avizandum

Correct II G with larger wheels.

Mike96Coupe

Thanks I appreciate it.

l98tpi

If running street tires you would be 1sg. If running race compound tires you would be 1g. You still have 17" diameter wheels, I don't think the 11" wide rears make a difference since the 96 Grand Sport which is a class G car had 11" wide rims on the rear.

Remember this, the only difference between Group 1S and 1 is the type of tires.

Gman57

Posted in NCCC rules
available on line

Refer to the Stock Wheel and Tire Size Chart posted on the Competition Section of the NCCC Website. (01/11)

1984-NEWER - Any type wheel with correct diameter & width for class & axle; adapters allowed
Req‟d.... group1s
Req‟d.... group1


1984-NEWER - any width wheel with minimum diameter of 16”, adapters allowed
No.... group1s
No.... group1

Tires
Notes:
1 - Cannot use recapped or Space Saver Spare tires.
2 - Cannot have cords showing.
3 - Refer to the Stock Wheel and Tire Size Chart posted on the Competition Section of the NCCC Website. (01/11)
1
Factory original tires, and replacement STREET tires with MINIMUM DOT wear rating of 110 manufactured with MINIMUM 8/32” tread depth NEW & HAVING 2/32” or more tread remaining (i.e., tread must be ABOVE wear bars).
+/- 10 mm tire width and/or +/- 5 aspect ratio allowed (01/10)
Group-1S tires not meeting minimum tread depth specification move car to Group-1
1984-NEWER - Tire size (diameter, width, & profile) MUST be correct for class & axle.
Req‟d.... group1s
NA.... group1

vettehardt

You would be a 1SG for your street tires.
Are your race tires DOT approved like hoosier or kumho's? If so you would be 1G.
If they are full slicks, that moves you all the way up to 3E.

You are allowed to run any wheels with the same size and offset as the stock wheels for your class for each axle (you cannot run your rears on the front). Since you are a LT1 you are in the G class. The G class includes the 96 grand sports with their 17X9.5 front and 17X11 in the rear. As long as your wheels are the same offset (50mm i think,) you are good to go. So with street tires, you are 1SG and with DOT race tires you are 1G.

Also in the street tire class, 1SG, you are allowed +/- 10mm from stock sizes. Since you are running 275 and 315, that is stock sizes. The tires must have originally been molded with greater than 8/32" tread depth and can not be lower than a 110 wear rating.

In 1G, you are allowed to run any DOT approved tire that safely fits on the stock rims.

In group 2 and 3 you are allowed to run any wheel you can fit on the car provided they are the minimum size stated in the rule book (16" for your car). Group 2 still requires DOT approved tires, but you can run any size. Group 3 is run what ever you want.

David
Pretty much the full time Indiana Region tech inspector.