Tires must meet the following requirements to be eligible for use in Max Category. No tire model will be eligible for Time Trials competition until it meets all requirements of this Section. Tire models not meeting the requirements by January 1 are not eligible for Time Trials competition until after the Time Trials National Championships of the year.

1. Original Equipment (OE) Tires
OE DOT-Approved Tires may be run providing the following conditions are met:

A. The tire size and model is as delivered from the factory on that model and trim level car. (E.g., The 100UTQG GoodYear Eagle F1 Supercar 305/30ZR19 (Front) and 325/30ZR19 (Rear) on the 2018 Chevrolet Camaro ZL1 1LE.)

B. The car is not prepped beyond Sport Category rules. (The car does not have to be classed in Sport Category, but its modification may not be beyond those rules.)

C. The tire must not appear on the following exclusion list, which may be altered at any time by the Time Trials Board (TTB) upon notification of membership.

There are no tires currently listed.

2. Aftermarket/Non-OE Tires

A. Specification

1. Minimum UTQG Treadwear Grade of 200.

2. Minimum molded tread depth of 7/32 inch as specified by the manufacturer.

3. Listed in a current year or prior two years of the “Tire Guide®” and/or the “Tread Design Guide®” (www.tireguides.com).

4. US Department of Transportation (DOT) approval.

5. Tires must be designed for highway use on passenger cars.

B. Eligibility Requirements:
The following are prerequisites before a tire can be used in competition at National Time Trials Events.

1. Tire availability: Tires are considered available when competitors can take possession through retail channels. Pre-orders are not considered available.

2. Tires must be equally available to all competitors. Tires that are in short supply do not specifically violate this Section. Extensive shortages may result in the tire being placed on the exclusion list until supply is replenished. Tire variations differing from standard specification, delivered only on a limited basis, or only to selected competitors may not be used.

3. Tire models must have tires available in at least four (4) rim diameters and in at least six (6) sizes which meet these requirements.

4. Material Change: Tires which previously met the eligibility requirements that undergo a significant compound change, tread pattern change, or other significant redesign reset the requirement for eligibility described in this Section.

5. A tire model which was previously allowed by these rules continues to be eligible for competition until specifically disallowed.

6. Reintroduction: Models that were once discontinued will be considered a new model once reintroduced and must meet all the requirements of this Section.

7. The tire must not appear on the following exclusion list, which may be altered at any time by the Time Trials Board (TTB) upon notification of membership.

- Kumho V720 ACR (less than minimum molded tread depth)

- Vitour Tempesta P1

3. Tire Use

A. Scored Sessions
Unless a “wet session” is declared by event officials, vehicles must run on the same set of tires for all scored competition rounds, and the tires should be marked with a stamp on grid of the first competition. Tires may also be replaced at the discretion of the Technical Chief in cases safety issues such as damage or excessive wear. (Entrants are warned that damage caused by deliberate abusive handling or deliberate shaving should not be given a replacement allowance.)

B. Unscored Sessions
Vehicles are required to practice on tires which are legal for scored sessions in their class, but do not have to be the same set.

4. Other

A. Tires may be shaved evenly and parallel to the axis of rotation, but may not otherwise be siped, grooved or modified.

B. Tires must have a minimum tread depth of 2/32nds at two (2) points 180 degrees apart.

C. No recap and/or retread tires may be used.

D. Excluded tires: Tires may be excluded for, but not limited to, low volume production, extensive availability limitations and specialty design.