Abstract: A pseudo crank rotational speed determining unit for a bicycle includes a speed determining unit which determines a speed of the bicycle and a pseudo crank rotational speed determining unit. The pseudo crank rotational speed determining unit operatively communicates with the speed determining unit and determines a pseudo crank rotational speed from the determined speed of the bicycle. In a more specific embodiment, a front gear identifying unit identifies a front gear of the bicycle, and a rear gear identifying unit identifies a rear gear of the bicycle. The pseudo crank rotational speed determining unit determines a gear ratio from the identified front gear and the identified rear gear, and then the pseudo crank rotational speed is determined from the determined speed of the bicycle and from the determined gear ratio.