How to Determine Tire Load Ratings
- 1). Determine the tire load index. The index will be two numbers and it appears with the speed rating which will be one letter in the service description. The load index ranges from 70 to 110.
- 2). Convert the tire load index number to the number of pounds the tire can support using a rating chart (See Resources). For example, if the tire's load index equals 97, the tire could support 1,609 pounds.
- 3). Locate the load range at the end of the service description on passenger tires or by locating the isolated letter in the middle of the service description on light truck tires. On passenger car tires, the load range may not appear, meaning it is a standard load tire, or it will be signified by "LL" for light load or "XL" for extra load. Light truck tires use a letter of the alphabet, usually between "B" and "F."
- 4). Convert the load rating to psi using a rating chart available online (See Resources). For example, a tire with "C" rating would need a load pressure of 50 psi.
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