Bicycle Tire Sizes Explained

23c 25c and 28c their width in mm.

Bicycle tire sizes explained.

While you can find a variety of bikes with wheel sizes ranging from 16 to 27 5 inches the most common sizes include 26 inches 27 5 inches 29 inches and 700c. Read the size carefully. Nowadays bicycle tire sizes are all marked according to etrto european tire and rim technical organization standard. Size variations of tubulars are covered in sutherland s handbook for bicycle mechanics 7th edition available from sutherland s and on the mechanic s bookshelf at better bike shops.

A hybrid of road and mountain tires cyclocross tires are labeled as 700c and have widths indicated in millimeters like road bikes yet are knobbie like mountain bike tires. When it comes to choosing width there are two major factors at play. 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. The etrto size specification 37 622 indicates the width of 37 mm and the tire inner diameter of 622 mm.

Sizes written as decimals such as 2 75 are different than sizes expressed as fractions such as 2 3 4. The table below lists most of the sizes of tyre that are likely to be found in the uk. A tire size you might see on a road bike. International organization for standardization.

Road bike tires generally come in three widths. There are five tire diameter sizes that are in common use on modern standard adult bicycles. Sizes of 26 and 24 tubulars are not well standardized. Where you see a block of two or more compatible sizes having the same bead diameter you can assume that intermediate sizes exist that will also fit the same rim.

A tire size you might see on a mountain bike. 27 iso size 630 is an older size that was used for road bikes but since so many bikes were built with this size it is still readily available. 700x25c indicates a tire with a 700mm outer diameter and a 25mm width. Finding the right inner tube depends on the size of the tires on your bike.

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. Take the rim with you when buying a tire and vice versa. Conversion tables for common bicycle tire sizes. 26 iso size 559 is the most commonly used size for modern mountain bikes and is also used by many hybrid bikes.

29 x 2 3 indicates a tire with a 29 outer diameter and a 2 3 width. However older english and french tire size dimensions are still used as well. A third type of tire size might appear on either a mountain or a road tire.