What Do The Numbers On Tires Mean?

If you’ve ever looked at the sidewall of a tire, you’ve probably noticed a series of numbers and letters. This tire code provides important information about the technical specifications of the tire. However, to the average person, this code can seem like an indiscernible language. So, what do the numbers on tires mean? Let’s break it down.

The number sequence on a tire usually appears in this format: P215/65R15 95H. Let’s deconstruct it:

1. The first letter “P” stands for passenger vehicle. This indicates the type of vehicle the tire is designed for. If there’s no letter, it means it’s a Euro-metric tire. Other letters you might see include LT (Light Truck), ST (Special Trailers), and T (Temporary Spare).

2. “215” is the tire width in millimeters from one sidewall to the other sidewall. In this case, the tire is 215 millimeters wide. The larger this number, the wider the tire.

3. The two-digit number following the slash mark “/65”is the aspect ratio, which represents the height of the tire sidewall as a percentage of the tire width. So in our example, the height of the tire is 65% of its width.

4. The “R” indicates the construction of the tire, with R standing for radial, which means the layers run radially across the tire. Other letters used are D for diagonal construction and B for belted.

5. “15” is the wheel diameter. This indicates the size of the wheel from one end to the other. The number is measured in inches, so a “15” means the tire is made for a 15-inch wheel.

6. “95” is the load index, which indicates the maximum load that the tire can support when properly inflated. Higher numbers indicate a higher carrying capacity.

7. The last letter “H” is the speed rating, which tells you the maximum service speed for the tire. An H-rated tire, for instance, has a maximum speed capability of 130 miles per hour.

Understanding the numbers and letters on a tire allows you to choose a tire that meets the specifications of your vehicle and also to compare tires for purchase. By knowing the meaning behind these numbers, you can ensure that you choose the right tires for your vehicle, resulting in a better and safer driving experience.