How to Read the Size and Model of a Motorcycle Inner Tube?
2 Answers
215 indicates the tire section width, measured in millimeters. 70 is the aspect ratio, representing the percentage ratio of the tire sidewall height to the tire section width, with 70 meaning 70%. R stands for Radial, indicating that the tire has a radial structure. 15 is the rim diameter, measured in inches.
I often encounter fellow riders asking about this during repairs. The most straightforward way to check a motorcycle inner tube size is to look for the numerical markings on the tire sidewall, usually in three sets of numbers, such as ‘3.00-17’. The first number, 3.00, indicates the tire width in inches (3 inches), and the number after the hyphen, 17, is the rim diameter in inches (17 inches). Some tubeless tires may be labeled as 90/90-18, where 90/90 refers to a width of 90 millimeters and an aspect ratio of 90%, and 18 is the rim size. It’s crucial to check the sidewall for wear or stains that might obscure the numbers. If the markings are unclear, you can measure the width and diameter of the old inner tube with a tape measure. The inner tube model must match the outer tire; otherwise, it may lead to blowouts or air leaks. If you’re unsure, the safest option is to take a photo and show it to a tire shop owner—they can instantly identify the correct model.
