A bicycle wheel rim can be worn down by rim brakes, leading to serious accidents. The present invention relates to a novel bicycle rim that provides direct and clear indication to a rider when a braking surface on the rim has been worn off. The novel bicycle rim comprises a base portion, two lateral flanks forming an outer braking surface, and a longitudinal hole. The braking surface has a first portion and a second portion. The first portion of the braking surface has a thickness that is designed to be worn off down to the longitudinal hole so as to form a visible slit, while the second portion, situated radially outwards with respect to the first portion, has a thickness such as to prevent deformations of the second portion when the first portion is worn off down to the longitudinal hole.