Article series: What do the numbers on the bicycle tire mean?

Tire inch size and English designation

Last updated: 2022-08-27

Tire label example

The specification 28x1.60 in the above example tire is the so-called inch size or English designation.

English short designation

Example: 28 x 1.60

The English short designation consists of two numbers. The first number, 28, means that the tire has an outer diameter of 28 inches (28" for short).

The second number, 1.60, indicates that the tire is approximately 1.60 inches (1.60" for short) wide when inflated, which is about 4.1 cm. The tire width is measured at the widest point of the tire, as shown on the following graph.

Measuring tire width

English long designation

Example: 28 x 1 5/8 x 1 3/8

The English long designation consists of three numbers. The first number, 28, also stands here for the tire outer diameter of 28 inches.

The second number, 1 5/8, indicates the tire height, i.e. the tire casing is approximately 1 5/8 inches high when inflated. Instead of the decimal places, a fraction is specified here. In decimal notation, this is 1.625 inches and is equivalent to about 4.1 cm.

The third number, 1 3/8, indicates the tire width, i.e. the tire is approximately 1 3/8 inch = 1.375 inch wide when inflated, which is about 3.5 cm.

Where does the tire show the inch size?

If you want to read off the "inches" from the bicycle tire or you are speaking of the inch size of the tire, the first number is always meant in the above examples, so in this case 28 inches (28" for short). So here we are talking about a 28-inch tire.

Note on buying tires

The inch specification is usually inaccurate and should not be used as the sole size specification when buying tires. The reason lies in the history: In the past, the inch specification was occasionally deliberately misstated for marketing purposes, for example, to be able to offer an even lighter tire than the competitors in the "same" size.

In addition, the inch specification does not indicate the matching rim size, so this can only be estimated indirectly via tire outer diameter and tire height. So there is a risk that the tire does not fit the existing rim.

So when buying a new tire to fit the existing rim, I always additionally pay attention to the ETRTO specification, as this indicates the exact rim size.

What do the other indications on the bicycle tire mean?

This article is part of a series of articles. For the other information on the bicycle tire see:

  1. ETRTO size of a bicycle tire
  2. Tire inch size and English designation (this article)
  3. Tire French size
  4. Bike tread specification

References