Use an online tire selector, like the one available at DunlopMotorcycle.com or DennisKirk.com, to find the right size of tire for a motorcycle. These tools help riders discover exactly what sizes the manufacturer recommends for the motorcycle and offer accurate results.
Entering the make, model and year of the motorcycle returns the original equipment manufacturer, or OEM, tire size. This size provides a large amount of information in a concise and easy-to-read format. The tire size delivers a formula, such as 180/60R16, that provides the information needed to ensure riders get the right size. In the example, 180 refers to the width of the tire in millimeters, and 60 is the aspect ratio, which appears as a percentage of the total width. The letter R is a speed code, in this case meaning mechanics should only install the tire on vehicles with a maximum speed of 106 miles per hour, and the number 16 refers to the diameter of the rim in inches.
Older tires and some specialty tires may still use other codes than the metric version. These codes, which resemble ML60R-16, provide the same information in a different format. ML is a code that translates to a 90-millimeter width, 60 refers to a 60 percent aspect ratio, R is the speed code, and 16 is the rim diameter in inches.