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How to Read a Tire’s Sidewall Correctly

The series of letters and numbers on the sidewall of your tires (Broad River Columbia SC) might seem gibberish, but rest assured, you don’t need secret decoding software to understand what they mean. Each symbol stands for a particular aspect so knowing their meaning is all the more useful when it is time to replace your tires.

Type: If you spot a letter P at the beginning, it indicates P metric tires made to certain standards within the United States, intended for Passenger vehicles. The letters LT at the beginning or end mean it was designed for light trucks. If there are no letters at the beginning, it is a Euro metric tire. Consult your owner’s manual or tire placard for the recommended tire size and inflation pressure for your vehicle.

Width: Tires are measured from one sidewall to another, and cited in millimeters. The first three-digit number appearing on the sidewall is the width. For instance, in a size P215/65 R15, the width is 215 millimeters.

Construction: Citing the example P215/65 R15, the R indicates Radial, which means the layers run radially across the tire. B means belted bias, while D is for diagonal bias construction.

Aspect Ratio: It is the ratio of the tire’s cross-section height to its width. The numbers appearing after type and width is the aspect ratio. If the numbers say P215/65 R15, it means the height is equal to 65% of the tire’s width. The size of the tire’s sidewall is proportion to the aspect ratio.

Wheel Diameter: The size of the wheel is measured from one end to another – you get to know to the size of the wheel that the tire is intended to fit. A P215/65 R15 tire is designed for wheels of 15-inch diameter.

Note: Type, Width, Aspect Ratio, Construction, and Wheel Diameter make up the tire size.

Load Index: This is the maximum load the tire is able to support when fully inflated. This number appears after the tire size. If it says P215/65 R15 98H, the load index, in this case, is 98. For U.S. passenger car tires, the load limit is listed in pounds. European tires have the load limit listed in kilograms and sometimes pounds.

Speed Rating: This is indicated by letters ranging from A to Z. For example, the speed rating of a tire P215/65 R15 98H, is H. Each letter coincides to the maximum speed a tire can sustain under its recommended load capacity. You can look up tire speed ratings online.
Now that you know exactly how to read a tire sidewall, this information will come in handy when there is a need for a replacement of tires in the Broad River, Columbia SC area. Come see New Vision Auto LLC for all of your tires, oil changes, and auto detailing needs.