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When it comes to selecting the right tires for your vehicle, knowing how to read tire sidewall markings and tire sizes can be incredibly beneficial. This knowledge can help you choose the correct tires that fit your rims, meet your driving needs, and comply with safety standards.

Which Tires Fit My Rims?

To determine which tires fit your rims, you need to look at the tire sidewall markings. Here are a few examples of tire sizes so you know what to look for: 205/55R16, P215/55R17, 215/55-17, and P215/65R15 95H. We will use these as examples as we move on.

Tire Type

The first part of the tire size may include a letter, which signifies the type of tire. For instance,

• "P" stands for Passenger Car Tires
• "LT" for Light Truck Tires
• "C" for Commercial Truck Tires
• "T" designates a temporary spare (often called a donut)
• "ST" is a special trailer tire

If there is no such designation, it is a metric size, often known as a Euro-metric size, as these sizes originated in Europe.

Section Width

The three-digit number that follows the tire type or the first letter is the Section Width. This number measures the width of the tire in millimeters. In the tire 205/55R16, the width of the tire is 205mm.

Aspect Ratio of the Sidewall

The next two-digit number represents the height of the tire, expressed as a percentage of the width. For example, in a 215/55-17 tire, the width is 215mm, and the height is 55% of that width.

Construction Type

This second set of numbers may be followed by a letter that indicates the construction type of the tire.

• "R" signifies Radial Tires, the most common type of tire sold since the 1970s
• "RF" stands for a special type of tire known as Run Flat Tires
• "D" indicates a bias-ply or Diagonal construction.

Wheel Diameter

This number, which is listed in inches, is the diameter of the wheel the tire is meant to fit. For example, in a 205/55R16 tire, the tire is meant to fit a 16 inch wheel.

Load Index

The two or three-digit number following the wheel diameter indicates the maximum load the tire can carry when properly inflated. For instance, in a P215/65R15 95H tire, the load index of 95 typically supports 1,521 pounds per tire.

Speed Rating

This is a letter on the tire which indicates the maximum speed at which the tire can safely operate. Using the same example as above, the H corresponds to a maximum speed of 130 mph.

For more questions about your specific tires, use our online tire finder or give us a call at (301) 585-2740.