How to Choose the Right Inner Tube

You have started cycling and have heard a couple of times about how important it is to carry an inner tube, especially if you are riding in remote areas where you might not get assistance in case of a flat tyre. But the question remains: How do you get the correct inner tube for your bike?

Inner Tube Size

To choose the correct inner tube size for your bike's tyre, you must consider both the diameter and width of the tyre. While bicycle tyres are specified with a particular width, such as 700 x 23, 700 x 25, or 700 x 28, inner tubes are typically classified within ranges. 

For example, an inner tube designed for a 700-diameter wheel might be labelled 700 x 23-32, indicating compatibility with tyre widths ranging from 23mm to 32mm. This flexibility in inner tube sizing allows for greater versatility and compatibility with a range of tyre widths. 

You can find the information regarding the tyre size by looking at the tyre's sidewall. For instance, on the Merida Scultura 100, the tyre displays "700x25c". Here, 700 represents the tyre's diameter in millimetres, while 25c represents the tyre's width in millimetres. The "c" indicates that the tyre's width measurement is in the ISO sizing system used for bicycle tyres. By matching the inner tube's width range to the tyre's width, you can ensure a proper fit and reliable performance for your bike.

Inner Tube Valve

Tyres have different types of valves. The most common are Schrader valves and Presta valves.

Schrader Valves

These are commonly used in lower-pressure tyres, such as city, mountain, or kids' bikes. Schrader valves have a small internal spring that keeps the valve closed when no external pressure is applied. You can depress the central pin with a narrow object to release air from a tyre with a Schrader valve.

Schrader valves have a larger diameter than narrow Presta valves, also known as French valves. Consequently, Schrader valves will not fit rims designed explicitly for narrow Presta valves.

Presta Valves

Presta valves are narrower and are commonly used in high-pressure applications, making them well-suited for road bikes, specific city bikes, and other wheels where pressures exceed 60 psi. Their narrower design necessitates a smaller valve hole, making them particularly popular for rims with narrower profiles, such as those on road bikes.