# How to Read Motorcycle Tire Sizes

by Tamara Runzel

Keeping good tires on your motorcycle is one of the main safety precautions you can take. If anything is wrong with either of your tires, you could end up in a serious accident. Putting the right tire on your motorcycle is just as important as maintaining your motorcycle tire. There are a variety of numbers on your motorcycle tire. These numbers represent the rotation direction of the tire, the load and pressure codes, when the tire was made and the tire size. Picking out which one represents the tire size is not too difficult.

### Metric Designation

1

Look at the outside of your motorcycle tire. You will see a series of numbers and letters, but the biggest numbers and letters represent the tire size. It should look similar to this set of numbers: 130/90 16.

2

Notice the first number. In our example, 130/90 16, the first number is 130. The 130 represents the width of the tire in millimeters. The width is measured from the outer edge of one side of the tire tread to the other.

3

Find the second number in that series. In our case, that number is 90. This number represents the ratio of the height of the tire to the width of the tire. You will look up the tire size using the 90, but if you wanted to find the height in millimeters, you can take: 130 X .9, which equals 117 millimeters. So, the height of this tire is 117 millimeters.

4

Locate the last number in the series. In our case, this number is 16. This number represents the diameter of the tire’s rim. The number is expressed in inches, rather than millimeters like the other two measurements.

### Alphabetical Designation

1

Locate the largest set of numbers on the side of your motorcycle tire. The first letter should be an “M”. Your code should look similar to this: MT90-16

2

Make sure the first letter is “M”. The “M” is used to denote that the tire is a motorcycle tire.

3

Identify the second letter. In our case, it is “T”. This letter is the tire width code. You can find the corresponding width in millimeters on any motorcycle tire chart.

4

Find the third number in the series. As in the metric designation, this number represents the ratio of the tire height to the width. In this case, the ratio of the height to the width is 90 percent.

5

Locate the final number in the series. This number, as in the metric designation, represents the diameter of the rim in inches.

#### Tip

• check Check your tires regularly to make sure they are in good shape. You should check for punctures, slashes and air pressure.