How to Read a Sidewall

Finding the tire size for your vehicle can be a little intimidating, but after reading this brief guide you will have all the info you need to find the right tire size for your vehicle.
Step 1 – Learn to recognize a tire size.  Most tire sizes appear in the following format: 225/60R16. The “225” is the section width (distance across the tread) measured in millimeters, the “60” is the aspect ratio (this is the measurement of the sidewall height as a percentage of the section width) and the “16” is the rim diameter measured in inches (or the diameter of the hole in the middle of the tire).  Most vehicles in the United States have a tire size that conforms to this tire size format.

Step 2 – Find your tire size.  Now that you know what to look for, we will tell you where to find it.  The best place to find your tire size is on the vehicle itself - your vehicle load and tire information placeard is usually located on the door jamb of the driver's door and will have the manufacturer recommended tire size(s) for your vehicle.  You can see an example of this below.



The second place to find your tire size is on the tire itself.  See image below to see where your tire size appears on your tire.

That wasn’t so bad was it!  Now that you have your tire size you are ready to shop for new replacement tires.

Step 3 – Additional Information.  In addition to the size described in “Step One” there are other important pieces of information that you can find out about your tire size. A. Service Description The tire service description is made up of two parts. The first is a two or three digit number indicating the "load index" of the tire. This determines the weight the tire can carry. When replacing tires, you should select a tire with the same or higher load index than what is listed on the tire information placard (not necessarily what is listed on your current tires). Following the load index number is a letter called the "speed rating". This letter determines the top speed this tire can handle. (In addition, higher speed ratings usually mean better handling.) In general, you should select a speed rating that indicates the same top speed or higher than what is listed on your tire information placard (not necessarily what is listed on your current tires). In the case of snow tires, it is ok to use a lower speed rating than what your vehicle indicates. (Note that speed rating top speeds do not follow alphabetical order, click here for speed rating values.) B. Mud & Snow Rating If your tire has the marking “M&S” on the sidewall this indicates that your tire is mud and snow rated.  Mud and snow rated tires meet the Rubber Manufacturers definition of a mud and snow tire – typically these tires are more aggressive and made to provide increased handling in mud and snow conditions. C.  Severe Snow Marking If your tire has the severe snow marking (see picture above) this means that the tire meets the Rubber Manufacturers Associations definition of a tire designed for use in severe snow conditions.