Bike Tire Sizes Explained

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.

Bike tire sizes explained.

Tubes because they can stretch will list a range of widths. Because of the high pressure and desired low rolling resistance road tires come in narrow widths. Bike tube sizing essentially mirrors bike tire sizing with one exception. The same size tire would be known by different numbers in different countries.

Conversion tables for common bicycle tire sizes. Road bike tires generally come in three widths. When it comes to choosing width there are two major factors at play. Nowadays bike tires are typically marked according to iso standard a system originally developed by etrto european tire and rim technical organization but older english and french tire size dimensions are still used as well use the data from the following tables to determine interchangeability and convert between iso etrto english.

International organization for standardization. Bicycle tires come in a bewildering variety of sizes. 23c 25c and 28c their width in mm. After the speed rating there will be a b or r to indicate if it is belted or radial tire construction.

27 5 x 1 9 2 3 for example. If there is no speed rating the m will precede the metric size. Common road bike widths in millimeters come in sizes ranging from 18 to 23 with a typical road bike tire at 700 x 23. Some older road bikes still have the 27 inch size.

Check out the following for 20 year old bike tires 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.