The service description is a combination of the load index (81) and the speed rating (H). If there is only one letter or a dash (-) after the aspect ratio, then it indicates construction type and the speed rating will appear in the service description.
You might see an “R” for Radial or a “D” for diagonal bias. If there are two letters after the aspect ratio, the first will be speed rating and the second will be tire construction. The letter(s) after the aspect ratio, in our case a “ B”, indicate speed rating and/or tire construction. In this case, the tire is 65 percent as tall as its width.ġ6 = The last number, 16, is the tire’s rim diameter expressed in inches. Simply put, the higher this number is, the taller the tire will be. This represents the aspect ratio between the tire’s width and its height or how tall a tire is in relationship to its width. We’ll get to the letters in a minute but here is what the individual numbers mean:ġ80 = the 180 designates the tire’s width in millimeters, measured in a straight line through the tire from one edge of the tire’s tread to the other.Ħ5 = The second number, 65, is a bit trickier to understand. Our example is a motorcycle tire sized at 180/65B16. Metric sizing is the most widely used and has the most information. It is important to understand these codes to insure you are getting a safe tire that will work on your particular motorcycle.ĭunlop tire codes utilize metric measurements. The alpha numerical coding on the sidewall of Dunlop motorcycle tires can be confusing.