How to Understand Motorcycle Tire Sizes

At first glance, you may think of a motorcycle tire code as nothing more than a strange jumble of letters and numbers. If you take a closer look, though, you will see a pattern among the chaos. In fact, the motorcycle tire code is designed to tell you everything you need to know about the tire. Since using the wrong size or wrong rating can be deadly, it is important to be able to read and understand the tire code when you purchase your tires.

Things You'll Need

• Motorcycle tire code

Instructions

1. Read the first number in the code. This is the tire's cross section width, or the maximum distance across the tire's cross section in millimeters. It may be presented in inches, although this is rare.

2. The second number is the aspect ratio given as a percent. This is the ratio between cross section height and the cross section width.

3. The third entry is the tire's construction code and will usually be one or two letters.

4. The fourth entry is the tire's rim size. Even if the cross section width is given in millimeters, the rim size will be given in inches.

5. Some tires will use "M/C" or similar abbreviation to indicate the tire is for a motorcycle. It will not always appear as part of the code.

6. Load and speed ratings as well as tread pattern codes may also be included in the overall code after the rim size or "M/C" if it is used.

Resources

• Motorcycle Tire Markings Chart
• Motorcycle Tire Speed Rating Codes
• Motorcycle Tire Cross Section Measurements