Your car’s tires may seem like such a simple thing. But, they are more than just black wheels of rubber that keep you moving on the road. In fact, they are more advanced than you might ever realize. If you ever want to know more about the tires on your car, just sit down next to one and read the sidewall. There is a lot of useful information printed right on your tire, but it can seem like a random jumble of letters and numbers unless you know what you’re looking for.
We’ll help break it down, so you know how to read your car’s tires.
In addition to the tire manufacturer and brand of tire, you should be able to find the maximum tire pressure, temperature grade, traction, tire width, aspect ratio, tread wear, service description, and DOT number.
Let’s say you are looking at your tire and you see a code that reads P215/65R 15 95H. Here is what that means.
The first letter (P) indicates the tires service description. P stands for “passenger car,” LT stands for Light Truck, ST for Special Trailer, and T for Temporary.
The next number (215) is the tire width—the distance from sidewall edge to sidewall edge measured in millimeters over the tire’s tread.
In our example, 65 is the aspect ratio. This represents the sidewall height compared to the width. So, our tire’s sidewall height is 65% of the tire’s width. In general, lower aspect ratios (55 or less) are for performance-oriented tires.
The next part of the code is the internal construction. For our example tire, this is the letter R. The letter R stands for radial construction and it’s the industry standard. You will see this letter on practically all tires.
Next up is the rim diameter (15). This number measure tells you the rim size in inches that the tire was designed to fit. The rim is the metal wheel on your car that the tire attaches to.
The next number is one of the most important on the tire—it is the load index (95). This number tells you how much weight each tire can support. The higher the number, the more weight it can take. However, the actual number doesn’t represent the weight. You have to look up the number, 95 in this instance, and check a Load-Carrying Capacity Per Tire chart. The number 95 means this tire can support up to 1,521 pounds. Multiply that number by four to make sure your tires can support your vehicle’s weight.
The final letter in our code is an H, which indicates the tire’s speed rating. This is the speed the tire was designed to withstand for long periods of time (H = 130 mph).
Another extremely useful piece of information on your tire is the maximum air pressure. Keep in mind, however, this isn’t the recommended air pressure; that number can be found on your doorjamb and in your owner’s manual.
If you have any questions about your tires, come visit us at Rothrock Motor Sales and we can help you. Whether it’s as simple as checking your tire pressure or buying a whole new set of tires, we are here for you.