How to Read Tire Size

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Regular maintenance appointments are strongly advised to help the chances of your car running as smoothly as intended for a long period of time. Tires are one part of the vehicle that may require the occasional replacement.

But unlike buying a new shirt,  Toyota tire sizes vary more than just small, medium, and large. So how do you know which size tire you should get for your vehicle? Looking at the markings that are located on the tire itself is a great place to start.

Even then, you may not fully comprehend what each letter and number represent. Here at Waldorf Toyota, we broke down each part of the tire size so drivers in Waldorf, Saint Charles, and La Plata can accurately read their tire size and purchase the correct tires for their vehicle. So if you need to change your Toyota's tires, or any vehicle, read on!

For visual purposes, we want to use an example tire size of “P245/65R17 98S” as a reference for each section below.

Tire Type

The first letter simply tells you which class your tire falls under. “P,” in the case of our example, means Passenger Car. You may also come across “LT,” or Light Truck.

Tire Width

The next three digits tell us the distance from one sidewall to the other. This measurement is expressed in millimeters. For our tire, you would record its width as 245 millimeters.

Aspect Ratio

The two digits following the slash mark are read as a percentage in relation to the tire’s width. So, since ours says 65, that means the height of the sidewall is 65 percent of the width of the tire.

Construction

The letter after the aspect ratio more times than not will be the letter R. This stands for radial, meaning the layers of the tire are arranged radially across it.

Wheel Diameter

Immediately following that letter, the next number tells us the wheel diameter. Measured in inches from one end to the other, this lets us know the size wheel that the tire is meant to fit. In our case, that would be 17 inches.

Load Index

Next up is finding out the maximum load your tire can support. The majority of passenger-car tires have a load index that ranges from 75 to 100. That index can then be converted to pounds by looking at the Tire Load Index Chart. Our example tire has an index of 98. After a quick glance at the chart, this equates to 1,653 pounds.

Speed Rating

The final letter found on your tire size marking is the maximum speed for a tire. Each letter correlates to a given speed in MPH. Ours has the letter S assigned to it, which the Tire Speed Rating Chart lists as a maximum speed of 112 MPH.

It’s important to note that no matter what the speed rating is, that doesn’t mean it is recommending you exceed the speed limit of the road or take corners at a fast speed.

Need More Information?

You may come across other things listed on your tire that you are unsure about. If that is the case or you need any more clarification on the information above about how to read your tire size, contact our team or come see us at Waldorf Toyota. We will be happy to answer any questions drivers in Waldorf, Saint Charles, and La Plata have!