What Do the Numbers On Your Tires Mean?

It’s not something you notice every day, but have you ever thought about the letters and numbers on your tires? Although they might look Greek to you, they actually do have meaning.

Why Are There Letters and Numbers on Your Tires?

Ultimately, the markings on your tires are there to help differentiate one type of tire from the next. There are so many tire variations based on performance, style, vehicle size, and more. That’s why there needed to be a standard code that would make the differences between each easily identifiable.

Understanding Your Tires’ ABCs and 123s

The letters and numbers on your tires won’t do any good if you don’t understand what they mean. Even if you’re not an expert mechanic, you’re sure to have to buy new tires at some point during your time as a vehicle owner. And, having a basic understanding of the markings on your tires will help you know what to look for.

Let’s take a look at a sample tire code, P 205/65 R15 92H, and break down what it means:

• Vehicle type: The starting letter (P in this case) indicates what type of vehicle this tire is intended for. P stands for Passenger, LT stands for Light Truck, and T is for Temporary (typically your spare tire).
• Section width: Next, you’ll see a number like 205. This indicates the width of the tire at its widest point, measured in millimeters.
• Aspect ratio: The second number, which is two digits, tells you what percentage the height of the sidewall is when compared to the section width. In this example, the height is 65% of its width.
• Tire design: Next in the tire code is a letter that denotes the tire’s design. R stands for Radial, B for Bias Belt, and D for Diagonal. The letter you’ll see most often here is R.
• Rim size: The two-digit number immediately after the tire design letter tells you what size rim should be used with this tire.
• Load index: The 92 in our sample tire code indicates how much weight a tire is meant to safely carry when it’s inflated to a specific level.
• Speed rating: The last letter, H in this case, stands for the maximum speed at which this tire can be used safely. A variety of letters can be used here including L, Q, S, T, U, H, V, W, Y, and Z. Tires with a Q rating can be used up to 100 mph while a Y-rated tire can safely go up to 186 mph.

Using the Numbers on Your Tires in Real Life

Now that you know what the letters and numbers on your tires mean, you can apply this knowledge to real-life situations. For example, in the unfortunate case that you have a flat, you’ll be able to know how fast you can safely drive on your spare tire by looking at its speed rating. Or, if you think you need new tires, knowing what the markings mean can help you compare your options.

At Good Works Auto Repair, we believe that informed consumers are able to make smart decisions about their vehicle’s care. That’s why we never get ‘tired’ of answering your questions about any vehicle-related topic. And, it’s why we provide a FREE Comprehensive Vehicle State of Health Check at every visit. We’ll let you know if we see any problems with your tires or other vehicle parts and systems. That way, you can fix small problems before they become big ones.

Simply give us a call today or schedule an appointment online!