Abstract: An electronic odometer and speedometer for bicycles computes distance and speed based upon input signals generated by interruption of a light beam by each spoke and the valve stem of a wheel of the bicycle. The interruption time of the light beam caused by the valve stem is substantially greater than that caused by the spokes; accordingly, it is readily detectable and the signal produced may be treated as a reference signal upon which the computations are based and the signals generated by the spokes provide a continuous real time update. Alternatively, the number of interruptions of the light beam per time, may be employed to compute the speed and the aggregate period of the number of interruptions may be employed to compute the distance. The light signal generating and detaching elements have non-movable parts and are mounted upon the frame of the bicycle without interfering with the normal removal and mounting of the wheel.