How to Read a Tire Sidewall

There is valuable information in that code on the side of your tire. Learn how to read it so you can use it when you need it.


  • Step 1: Consider the first letter Consider the first letter in the code. A designation of P means the tire was designed for passenger cars. LT indicates a light truck.
  • Step 2: Consider the bracketed numbers Consider the next set of numbers, separated by a slash. The first number is the width of the tire in millimeters from sidewall to sidewall. The second number is the ratio of the sidewall height to the tire's width as a percentage.
  • Step 3: Consider the construction code Consider the letter that follows the pair of slashed numbers. It indicates how the tire was constructed.
  • TIP: The letter R stands for radial and B stands for a tire whose layers run diagonally.
  • Step 4: Consider the maximum load Consider the next numbers in the sequence. This is the maximum load in pounds that the tire can support when properly inflated.
  • Step 5: Consider the speed rating Consider the final letter in the code. This is the speed rating or maximum service speed for the tire. The letter S indicates a maximum service speed of 112 miles per hour. A rating of A1 corresponds to 3 miles per hour.
  • Step 6: Drive according to indications Drive according to the specifications indicated on your tires, and you'll be safer and need less maintenance.
  • FACT: The U.S. Department of Transportation rates tires on the basis of tread wear, traction, and temperature resistance.

You Will Need

  • Tire

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