Tire Quality
You must not only be certain you purchase the correct size tires, but you must also try to obtain the best tire quality for your money. All tires are not created equal because tire quality is based on three characteristics: temperature, traction, and tread wear. Manufacturers use the Uniform Tire Quality Grading System (UTQGS) to indicate specific quality attributes of their tires. The UTQGS grades are used to rate the tires as follows:
Temperature: A, B, or C grade represents ability to resist heat buildup under laboratory conditions, since heat can shorten a tire's life or lead to tire failure. A is the highest grade while C is the minimum acceptable. This rating is based upon a normally loaded and properly inflated tire. Improper tire conditions such as overloading, underinflation, and/or extreme speed can cause heat generation and tire failure. That is why heat resistance is important.
Traction: A, B, or C grade represents traction ability, or skid resistance, as measured in straight line braking on wet asphalt and concrete. A is the best and C is the minimum acceptable. This grade does not measure traction in cornering. Traction ability is important for control of your car.
Tread wear: A number representing the durability of the tire tread. The rating is on a linear scale relative to 100, which is defined as being average. A tire rated at 150 tread wear should last 1.5 times as long, under normal driving conditions, as the average tire. However, tread life is difficult to estimate because your actual road conditions, climate, driving habits, and tire maintenance activities may differ from test conditions.
The UTQGS marks can be found on the tire sidewall too. The letter grades will be enclosed in a circle. UTQGS grades do not apply to temporary spares, winter tires, deep tread tires, or smaller tires with 10-12 inch rim diameters.
Always try to purchase tires with UTQGS marks of A for temperature, A for traction, and at least 100 for tread wear.