When it comes to replacing your inner tube, how do you know which size you need for your bike? There are a myriad of wheel sizes for road, MTB, touring and children’s bikes. MTB wheels, in particular, can be further categorised by 26 inches, 27.5 inches and 29 inches. To confuse matters further all tyres use the European Tyre and Rim Technical Organisation (ETRTO) system, so for a road, it would display 622 x nn with the nn value indicating the tyre width which is the same as 700 x nn. This value is displayed on the tyre wall, the first place to check for your tyre size. Once you know this you can then determine the size of tube you need. Some tubes will display 700 x 20-28c so this will fit tyres with a width between 20 and 28c.
You must make sure you replace your inner tubes with a tube that is the right size according to the diameter and width for your tyre. The size is almost always written somewhere on the sidewall of the tyre. Inner tubes typically state a wheel diameter and width range for which they will work, e.g. 26 x 1.95-2.125″, indicating that the tube is intended to fit a 26 inch tyre with a width of between 1.95 inches and 2.125 inches.
Another example might be 700 x 18-23c, which seems less obvious but 700c is the diameter of Road, Cyclocross, Adventure Road and Hybrid bike wheels, and the numbers relate to the width in millimetres, so 18mm-23mm wide. Many Road tyres are now 25mm and Cyclocross, Touring and Hybrid bike wheels may have tyres fitted that are up to 36mm so make sure you carry the appropriate width tube.
Post time: Jan-14-2021