Why check the correspondence of a tire and a bike rim ?
The compatibility of a bicycle tire with the rim on which it will be assembled is one of the criteria for choosing a tire. Indeed, a rim that is unsuitable for the tire it supports can have an impact on your safety because a rim that is too wide or too narrow will not allow the tire to hold properly in the rim hooks, especially when cornering, the risk of Toe-in of the inner tube will also be increased.
Methodology for matching bike rim tire size:
Whatever the type of bike or the level of riding, it is necessary to choose a tire compatible with the rims of your bike. A bicycle rim is designed with hooks in which the tire locks under the effect of pressure. the width of the rim determines the width between these hooks which will receive the tire. You must therefore ensure that the width of the rim and the width of the tire are designed to fit together.
1/ Determine the width of the rim:
Generally the width of the rim is written on one of the exterior faces of the rim, the value followed by a C corresponds to this width. If no inscription is present, it is in this case necessary to measure the rim using a caliper.
2/ How to identify the width of the tire:
The width of the tire is written on its sidewalls.
3/ Understand the ETRTO standard and bicycle rim tire size correspondence table
The ETRTO (European Tire and Rim Technical Organisation) standard is an international reference which guarantees compatibility between tires and rims. It expresses dimensions in millimeters, unlike traditional systems such as inches, which are often subject to confusion. This is how an ETRTO reference reads:
Tire width: expressed in millimeters.
Inside diameter of the tire (or rim diameter): also expressed in millimeters.
For example, a tire with the inscription 37-622 means:
37 mm: tire width.
622 mm: inner diameter of the tire, corresponding to the outer diameter of the rim.
Here is a simplified correspondence table based on the standard dimensions of the ETRTO standard.
ETRTO rim-tyre correspondence table
| Rim with (en mm) | Recommended tire width (en mm) | Examples of ETRTO tire dimensions |
|---|---|---|
| 13 | 18 à 25 | 18-622, 23-622, 25-622 |
| 15 | 23 à 32 | 23-622, 28-622, 32-622 |
| 17 | 25 à 37 | 25-622, 30-622, 37-622 |
| 19 | 28 à 47 | 28-622, 40-622, 47-622 |
| 21 | 35 à 50 | 35-622, 42-622, 50-622 |
| 23 | 40 à 62 | 40-622, 50-622, 57-622 |
| 25 | 45 à 76 | 45-622, 50-622, 70-622 |
| 27 | 50 à 89 | 50-622, 60-622, 80-622 |
Bike tire rim size matching tool
Important points to remember
Essential Compatibility: To avoid safety or performance issues, always respect the compatibility range between rim width and tire width.
Pressure and width: A wide tire on a narrow rim can cause excessive tire deformation, while a tire that is too narrow on a wide rim reduces comfort and grip.
Practical use:
Narrow tires (18-25mm) are suitable for road bikes and offer low rolling resistance.
Wide tires (40 mm and more) are designed for mountain bikes or urban bikes, favoring comfort and grip.