7. Wheels/Tires
a. Any wheel/tire may be used within the following limitations:
1. Cars may not fit wheel diameters larger than those listed on their spec line. Knockoff/quickchange type wheels are prohibited. Wheels must be made of metal.
2. Tires must conform to 9.3.45.
3. Track may be changed to accommodate larger tires, provided that there is safe tire/fender/chassis clearance under all conditions of steer, bump, and rebound. Wheel spacers are permitted.
4. Tire tread (that portion of the tire that contacts the ground under static conditions) shall not protrude beyond the fender opening when viewed from the top perpendicular to the ground. To determine compliance, the vehicle should be rolled through a powdered substance, as raced with driver, in order to indicate the tire tread contact patch under static conditions.
5. Any wheel stud, bolt, and or nut is permitted.
6. Maximum allowable rim widths: ITR - 8.5 inches, classes ITS and ITA -seven (7) inches; classes ITB and ITC -six (6) inches.