How to Read Tire Size


Have you ever glanced at that series of numbers and letters on the sides of your tires and wondered what that all means? That string of symbols actually contains a sequence of information referred to as the tire size code. Because this information is so important, the tire shop here at Faulkner Volkswagen thought it would be a good idea to take the time to review each aspect for our Mechanicsburg, Camp Hill, and Harrisburg area drivers.

Here’s an example tire size to refer to as you’re following along: P165 / 65 R14 79 H.

Type of Tire


Beginning all the way over on the far left of our example tire size, we see that this one starts with the letter P. The P stands for P-Metric. A P-Metric tire is one that has been manufactured according to the passenger vehicle guidelines of the United States. If there was an LT at either the beginning or the end of this code, you would know that it was designated to be used on a light truck.

The Tire’s Width

Following the P is the number 165. This is the width of the tire measured from sidewall to sidewall in millimeters.

Aspect Ratio

The 65 on the right side of the slash mark is the tire’s aspect ratio. It lets you know that the height of the tire is 65% of the width.

Tire Construction

The letter that comes next tells you how the tire was put together. The R on this tire means that it’s a radial tire. Radial tires are the most common type of tire on the road today.

Wheel Diameter

Next up is wheel diameter. For this tire, you know that it is designed to fit onto a wheel that has a 14-inch diameter.

Load Index Number

How to read tire size

The load index number on our example tire size is 79. This number corresponds to the tire’s maximum load capacity in the load index and tells you the highest amount of weight that the tire is designed to hold.

Speed Rating

Finally, there’s the speed rating. Similar to the load index number that comes before it, this item matches to the tire’s maximum speed. As you can see, our example tire has an H as its speed rating. This lets you know that it is designed to go no faster than 130 miles per hour.

Be Sure to Maintain Your Tires

From your tire’s width to its speed rating, there’s a lot of information contained within that single line of letters and numbers. If you have any questions about the tire size code on your tires, feel free to email, call, or stop by.

If it’s time for a new set of tires, you’ve noticed that your tires appear to be getting pretty worn down, they don’t seem to offer that same level of traction that they used to, or you’d simply like to have them rotated, contact the Faulkner Volkswagen tire shop serving Mechanicsburg, Camp Hill, and Harrisburg to schedule an appointment.