To find the right size inner tube for your bicycle tire, look at the sidewall of the tire to find the ETRTO and metric or imperial sizes, and examine the valve type. The type of bike you own allows you to determine the best size measurement to use.
- Examine the sidewall of the tire
Bicycle tires give two measurements: ETRTO and metric or imperial. The ETRTO size was developed by the European Tyre and Rim Technical Organisation, and it is a more accurate measurement of the width and rim of the tire in millimeters. An example of an ETRTO size is 54-559. The metric or imperial size follows the ETRTO size. Examples of metric sizes are 26x2.1 and 700x23c.
- Determine your valve type
Bicycle tire tubes comes in two valve types, Presta and Schrader. The Schrader valve is the same type found on cars and is commonly used for bikes that require lower-pressure tires. The Presta valve is popular for racing and road bicycles, which require a higher-pressure tire. The Presta valve can be identified by the valve cap at the top.
- Select the best size
The metric or imperial measurements are slightly less accurate but are typically much easier to remember. The ETRTO size is especially recommended for touring, folding and older 3-speed bicycles. To ensure the best fit, use the ETRTO size for inner tubes.