Bike Tire Sizes Explained

While the first number the diameter of the tire is most important in identifying size there s a little more to how tires are measured with a more globally unified approach.

Bike tire sizes explained.

To make matters worse in the early days of cycling every country that manufactured bicycles developed its own system of marking the sizes. International organization for standardization. If there is no speed rating the m will precede the metric size. Road bike tires generally come in three widths.

When it comes to choosing width there are two major factors at play. 23c 25c and 28c their width in mm. Tubes because they can stretch will list a range of widths. Check out the following for 20 year old bike tires sizes explained.

27 5 x 1 9 2 3 for example. Because of the high pressure and desired low rolling resistance road tires come in narrow widths. After the speed rating there will be a b or r to indicate if it is belted or radial tire construction. Bicycle tires come in a bewildering variety of sizes.

Bike tube sizing essentially mirrors bike tire sizing with one exception. Metric tires are most commonly used and can work for sport bikes cruisers touring bikes and others. The same size tire would be known by different numbers in different countries. The letter at the end of a tire size is a throwback to an old french system when the letters a b and c designated different inner tire diameters it does not stand for cm.

Common road bike widths in millimeters come in sizes ranging from 18 to 23 with a typical road bike tire at 700 x 23. Thus you need to be sure any new bike tube has sizing that has a width range that aligns with the sizing on your bike tires.