Reading the info on the side of a tire

TransAm

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Reading A Tire

Everything You Need To Know — Your Sidewall Has It
The side of your tire — known as the sidewall — contains all of the information you need to know about your tire. Whether your tire comes from Goodyear or some other manufacturer, all tires are required to show this information.
For examples of sidewall abbreviations,
Tire Type defines the proper use of the tire. For example, the “P” on the tire shown here means that this is a passenger car tire. If the tire had an “LT” designation, the tire would be for a light truck.
Tire Width is the width of the tire measured in millimeters from sidewall to sidewall. This tire width is 215 millimeters.
Aspect Ratio is the ratio of the height of the tire's cross-section to its width. On our example, 65 means that the height is equal to 65% of the tire's width.
Construction tells you how the layers of the tire were put together. The “R” stands for Radial which means the layers run radially across the tire. A “B” stands for bias construction which means that the layers run diagonally.
Wheel Diameter is the width of the wheel from one end to the other. The diameter of this wheel is 15 inches.
Load Index indicates the maximum load in pounds that the tire can support when properly inflated. You'll also find the maximum load elsewhere on the tire sidewall, both in pounds and kilograms.
Speed Rating tells you the maximum service speed for a tire. “H” means that the tire has a maximum service speed of 130 mph. This rating relates only to tire speed capability and is NOT a recommendation to exceed legally posted speed limits.

Speed Ratings*

Many Goodyear tires are available in speed-rated versions to match the speed capabilities of the world’s fastest cars. Generally, it is recommended that a speed-rated tire be replaced with a tire having an equivalent or greater speed rating.
However, if you never drive at speeds near the limits of your speed rated tires, you may choose to replace them with tires having a lesser top-speed rating.
In situations where tires having different top-speed ratings are mixed on a vehicle, the maximum speed certification is limited to the top-speed certification of the tire with the lowest speed rating.
Speed ratings do not indicate how well a tire handles or corners. They certify the tire’s ability to withstand high speed.
*The Goodyear Tire & Rubber Company does not recommend the use of its products in excess of the legal speed limits.

DOT means that the tire complies with all applicable safety standards established by the U.S. Department of Transportation (DOT). Next to this is a tire identification or serial number — a combination of numbers and letters up to 12 digits.
UTQG stands for Uniform Tire Quality Grading, a rating system developed by DOT. For more information on UTQG,

Tire Grades: Uniform Tire Quality Grading System (UTQG)

Except for snow tires, the DOT requires the manufacturers to grade passenger car tires based on three performance factors: tread wear, traction, and temperature resistance. The UTQG rating of each Goodyear passenger car and light truck tire is listed in the Car/Light Truck Tire Catalog.

Tread Wear
  • More Than 100 - Better
  • 100 - Baseline
  • Less Than 100 - Poorer
The tread wear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. A tire graded 200 would wear twice as long on the government test track as one graded 100. Your actual tire mileage depends upon the conditions of their use and may vary due to driving habits, service practices, differences in road characteristics and climate. Note: Tread wear grades are valid only for comparisons within a manufacturer's product line. They are not valid for comparisons between manufacturers.

Traction
  • A - Best
  • B - Intermediate
  • C - Acceptable
Traction 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. The Traction grade is based upon "straight ahead" braking tests; it does not indicate cornering ability.

Temperature
  • A - Best
  • B - Intermediate
  • C - Acceptable
The temperature grades represent the tire's resistance to the generation of heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperatures can cause the materials of the tire to degenerate and thus reduce tire life. Excessive temperatures can lead to tire failure. Federal law requires that all tires meet at least the minimal requirements of Grade C.