A bicycle display apparatus comprises a display device adapted to be mounted to the bicycle, wherein the display device displays various types of information to a rider; a light sensor; and a display control element operatively coupled to the display device and to the light sensor for controlling the display device in accordance with signals from the light sensor. An apparatus provided for shifting a bicycle transmission having a plurality of gear positions comprises a running condition detector that detects a running condition of the bicycle; a light sensor; and a gearshift control element operatively coupled to the running condition detector and to the light sensor and providing a control signal for controlling the bicycle transmission in accordance with signals from the light sensor.