How do car manufacturers determine the size of your car’s tires? The following information should be helpful. First, know that a tire section width is different from its tread width. Tire section width is the distance from the sidewall edge to the tread area of the tire. It implies that the tire is installed on the rim under inflation pressure. In some cases, people who think their car’s tires are undersized measure the tread width. They install a wider tire than the one specified, expecting it to match the figure they’ve read. They are a bit upset when they don’t get the desired result. Also, you should know that tire manufacturers have a tolerance range of +/-3%.
The recommended tire size is listed in the door jamb of your car. Adding a larger tire to your car’s wheels may throw off the gearing and cause the car to have a slower acceleration rate and change the speedometer reading. You can also consult your vehicle’s owner’s manual for the recommended tire size. If you’re unsure, try a tire size calculator online or visit a local tire shop.
The load index of your tires is another important metric for choosing the correct size of tires. Light truck tires are classified according to their load index. This number varies from B to F, with most falling into the load ranges C, D, and E. You can use the load index table to determine the maximum load each tire can support. For example, if your car’s tire has a load index of 95, it can hold up to 1,521 pounds. On the other hand, a tire with a load index of 126 can support up to 3,748 pounds.