The invention relates to a rotor arrangement (4) for a drive motor (2) of a bicycle, comprising: - a cylindrical magnetic return path element (12); and - permanent magnets (8) which are arranged on the magnetic return path element (12) with a radial direction of polarity in the circumferential direction in order to form the rotor poles (14), characterized in that the magnetic return path element (12) has recesses (13) which are spaced apart from one another and in which the permanent magnets (8) are arranged, so that rotor poles (14) are formed by a region of the magnetic return path element (12), which region is situated between the recesses (13), and the permanent magnets (8).