What is the best rim width for gravel bike wheels?

Understand that rim width has “inside rim width” and "outside rim width

First of all, you should know that rim width has two values in the specifications. The first thing to know is that rim width has two values in the specifications: “inside rim width” and “outside rim width”.

“Inside rim width” is the width of the area where the tire is fitted.

When selecting a tire, the “inside rim width” is the width of the part of the rim where the tire is mounted (or the width between the hooks if the rim has hooks).

For example, when we say “19C wide rim,” whether it is wide or wide depends on whether it is inner or outer width. For example, a rim with an outer width of 19 mm would have an inner width of about 17 mm, so it cannot be called a wide rim today.

On the other hand, a rim with an inner width of 19 mm can be considered a relatively wide rim that can accommodate tires up to about 35C.

“Outer rim width” is the width of the entire wheel rim.

On the other hand, “outer rim width” is the width of the entire rim, so it refers to the distance between the outside and inside of the rim. If you are concerned about rim width when choosing gravel bike wheels, it is most likely that you want to install wider tires, so you should not be too concerned about the outer width of the rim.

However, if there is a numerical difference between the inner and outer widths of the rim, it means that the wall of the rim is thicker, so the weight of the rim is heavier and the overall wheel is likely to be heavier.

The rim width of a wheel is best determined based on the width of the tire you want to install

Currently, the most common wheel rim widths for road bike wheels are 17mm (17C) or 19mm (19C), which are wide rims. However, 17mm and 19mm rim widths are designed to maximize the aerodynamic effect when fitted with narrow tires such as 25C and 28C tires, which are not fitted on gravel bikes.

On the other hand, wheels designed for gravel bikes place more emphasis on increasing air volume with larger tires than on aero effect, so they have a much wider inner rim width.

For example, Mavic’s KSYRIUM SL DISC road aluminum wheel and its gravel version, the ALLROAD SL DISC, are similar wheels, but while the KSYRIUM SL DISC has a rim inner width of 19mm, the ALLROAD SL DISC has a rim KSYRIUM SL DISC has a rim inner width of 19mm, while ALLROAD SL DISC has a rim inner width of 22mm, 3mm wider.

These differences are also reflected in the recommended tire size: KSYRIUM SL DISC has a recommended tire size of 25 to 32 mm, while ALLROAD SL DISC has a much wider tire size of 28 to 64 mm.

If you want to mount a slightly narrower tire (for a gravel bike) of about 30C on a gravel bike, the KSYRIUM SL DISC with a rim inner width of 19mm is fine, but if you want to mount a larger tire of 38C or 40C, which are chosen for gravel bikes, the ALLROAD SL DISC You will have to choose the ALLROAD SL DISC.

In this way, the inner width of the rim that you should pay attention to when choosing a wheel depends on the size of the tire you want to install. Therefore, it can be said that the decision should be made based on "How big a tire do you want to fit?

Wheels with a “rim inner width of about 22 to 23 mm” are best for gravel bikes

The biggest advantage of gravel bikes is that they can be equipped with large tires, such as 40C, to increase their running performance and enjoy gravel and other rough terrain, but when riding on paved roads, large tires can also be a hindrance. It is more convenient to have tires mounted on gravel bikes with a certain width.

For example, if you use a gravel bike for everyday use or cycling, install a narrower tire (28C) to reduce rolling resistance and lighten the ride, and replace it with a larger tire (40C) only when you know you will be riding on gravel, making it a versatile bike that can do multiple things on a single bike. If you use a larger tire such as 40C only when you know you will be riding on gravel, you will have a versatile bike that can handle multiple tasks.

If you choose a wheel with an inner rim width of 19mm, you can optimize it for light and thin tires, but you will have the disadvantage of not being able to mount a larger tire such as 40C (not impossible, but not recommended by the manufacturer).

Currently, the most common wheels for gravel bikes are 22 to 23 mm inside rim width, and you can be sure that you will be able to choose the best wheels for your needs.