The following information relates to the system developed by the United States National Highway Traffic Safety Administration (NHTSA), which grades tires by treadwear, traction, and temperature performance. This applies only to vehicles sold in the United States. The grades are molded on the sidewalls of most passenger car tires. The Uniform Tire Quality Grading (UTQG) system does not apply to deep tread, winter tires, compact spare tires, tires with nominal rim diameters of 10 to 12 inches (25 to 30 cm), or to some limited-production tires.
While the tires available on General Motors passenger cars and light trucks may vary with respect to these grades, they must also conform to federal safety requirements and additional General Motors Tire Performance Criteria (TPC) standards.
Quality grades can be found where applicable on the tire sidewall between tread shoulder and maximum section width. For example:
Treadwear 200 Traction AA Temperature A
All Passenger Car Tires Must Conform to Federal Safety Requirements In Addition To These Grades.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one-half (1½) times as well on the government course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate.
Traction
The traction grades, from highest to lowest, are AA, A, B, and C. Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance.
Warning: The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics.
Temperature
The temperature grades are A (the highest), B, and C, representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law. Warning: The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.
Finish Care
Application of aftermarket clearcoat sealant/wax materials is not recommended.
If painted surfaces are damaged, see your dealer to have the damage assessed and
repaired. Foreign materials such as calcium chloride and other salts, ice melting
agents, road oil and tar, tree sap, bird droppings, ...
Driving on Wet Roads
Rain and wet roads can reduce vehicle traction and affect your ability to stop
and accelerate.
Always drive slower in these types of driving conditions and avoid driving through
large puddles and deep-standing or flowing water.
Warning
Wet brakes can cause crashes.
They might not work as wel ...
Cruise Control
If equipped with cruise control, the vehicle can maintain a speed of about 40
km/h (25 mph) or more without keeping your foot on the accelerator. Cruise control
does not work at speeds below 40 km/h (25 mph).
Warning
Cruise control can be dangerous where you cannot drive safely
at a steady s ...