Mountain Bike Inner Tubes Selection Assistant

The width of your tyre determines which inner tube size you need. You can find this size printed on the side of your tyre, which on mountain bikes is often indicated in inches. The sizing then includes the wheel size (e.g. 29 inches) and the width (e.g. 2.20 inches), as in this example: 29 x 2.20". If you don't see that but, rather, a size such as 55-622, the two-digit number (e.g. 55 here) refers to the tyre width in millimetres.