Abstract: A safety device for use in combination with a bicycle wheel having a hub, a rim and spokes connecting the hub to the rim is provided. The safety device comprises safety light means and means for powering the safety light. The safety light means comprises socket means for receiving an electric light bulb, a housing for containing the socket means and light bulb, the housing having light transmissive side walls, and means for clamping the housing to the spokes of the wheel with the light transmissive side walls facing laterally away from the wheel. The means for powering the safety light comprises a housing for receiving at least one dry cell battery, means for clamping the battery housing to the hub, respective electrically conductive means attached to the housing for contacting the respective poles of the battery and means for electrically connecting the battery in series with the socket means.