What information is in a tire rating guide?


Quick Answer

Tires carry a coded marks on their sides that give the tires' load carrying capacity and maximum speed capabilities. In some tires, the inside contains information not found on the outer sidewall.

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What information is in a tire rating guide?
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Full Answer

The rating guide system has the ISO metric tire code consisting of a string of letters and numbers. An example of a tire code is P195/60R15 87S. This rating index must be in all tires manufactured from 1991 to date.

87S refers to the load index of a tire. This is an assigned value indicating the tire’s relative load carrying capabilities. In this case, 87S indicates that the tire can carry up to approximately 1201 pounds. Tires with a higher index can carry higher amounts of weight than those with low indexes.

The tire rating guide also gives the speed rating. In the figure 60R15, the "R" symbol shows that the tire can run at a maximum speed of 170 kph and is suitable for light trucks. In different tires, there are different symbols that indicate the different maximum speeds of each. Over time, tire ratings are evolving to better identify a tire’s capability, allowing drivers to match the speed of their tires with the top speed of their vehicle.

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