Guide to Tire Size Markings and Tire Markings

Markings on American Tires

In the United States, every tire is required by federal law to receive approval by the Department of Transportation (DOT) before entering the market. Accepted tires meet the minimum standards for safety. This process involves receiving unique markings to denote size, age, manufacturer and other criteria to inform the consumer about where their tires came from, and whether or not they need replacing because they’re growing too old. All drivers must be made cognizant of the required tire markings in order to maximize their chances of staying safe while on the road.

Tire Size Markings

In the image below, the tire size is listed as 185/60R14. Markings such as this break down in the following manner:

How Uniform Tire Quality Grading Marking Works

By law, all tire manufacturers are required to grade their tires under the DOT’s Uniform Tire Quality Grade (UTQG) labeling system. Temperature resistance, treadware and traction comprise the testing rubric, which is applied independently on a manufacturer-by-manufacturer basis. These involve assigning values to the federal tire safety guidelines and comparing the test tire with a control. It is important to note that treadware ratings are set by the manufacturers rather than the DOT, so only temperature resistance and traction get held to a standard performance level. Because of this, treadware numbers are best compared to other tires produced by the same company.

Tire Markings Indicating Tire Size

When trying to glean a tire’s size, look for the markings on its sidewall. In this example, we’ll break down P185/60R14 82H.

Steven J. Sharp
Public Service Award

Mr. Willis received this award for his work in uncovering the truth behind the 2001 Ford Explorer and Firestone litigation that resulted in millions of tire recalls.

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