Bicycle wheel rim with surface region for brake unit

摘要

The bicycle rim has an indicator to indicate when the wall thickness of the rim (1) has been reduced to a preset minimum value, due to material removal (3,3) by the use of the brakes. The indicator can be a depression provided in the rim, which has a hemispherical or conical shape. Several indicators can be provided, such as three spaced apart at 120 degrees. The indicator can be a layer under the surface of the rim which changes colour, or it can be an electronic sensor located in the rim wall, or its interior. This measures the distance to the applied brakes by electrical capacity or inductance examination.