Tires are a significant part of your vehicle. They are the only parts that come into contact with the road, and they play a crucial role in the vehicle's handling, performance, and safety. If you've ever looked at a tire, you may have noticed that it has a series of numbers and letters on its sidewall. These numbers and letters provide important information about the tire's size, type, and performance capabilities. In this blog, we will explore what these numbers mean and how they can help you choose the right tire for your vehicle.
Tire Size
The first set of numbers on a tire's sidewall represents its size. The size is usually expressed in a format such as P215/60R16. Let's break down what each part of the size number means:
- P: This letter stands for the tire's service type. In this case, P stands for "passenger" tire.
- 215: This number represents the tire's width in millimeters from sidewall to sidewall when measured on the widest point of the tire - the tire is 215 millimeters wide.
- 60: This number represents the tire's aspect ratio, which is the ratio of the tire's height to its width - the tire's height is 60% of its width.
- R: This letter stands for "radial," which means that the tire has radial construction.
- 16: This number represents the diameter of the tire in inches. In this case, the tire's diameter is 16 inches.
Load Index and Speed Rating
The next set of numbers and letters on a tire's sidewall is the load index and speed rating. These numbers and letters indicate the maximum load capacity and speed capability of the tire. For example, a tire with a load index of 95 can carry a maximum load of 1,521 pounds, while a tire with a speed rating of V can go at a max speed of 149 miles per hour. You can find spreadsheets with all other numbers online.
Treadwear, Traction, and Temperature Grades
The final numbers and letters represent its treadwear, traction, and temperature grades. These grades are assigned by the tire manufacturer and indicate the tire's performance in three important areas:
Treadwear grade: This number indicates how long the tire is expected to last. The higher the number, the longer it lasts.
Traction grade: The tire's ability to stop on wet roads. The grades range from AA (highest) to C (lowest).
Temperature grade: This shows the tire's ability to dissipate heat. Grades range from A (highest) to C (lowest).
The numbers and letters on a tire's sidewall provide vital information about the tire's size, load capacity, speed capability, and performance characteristics. By understanding them, you can choose the right tire for your vehicle and ensure that it performs optimally and safely. Be sure to consult with the tire experts at Dave's Automotive if you have any questions about choosing the right tire for your vehicle.