Various electronic accessories, such as on-board computers, communication devices, and wireless sensor nodes, have been installed on bicycles for several years. A powering scheme from ambient energy could avoid the use of batteries and improve the availability of these devices even when the bicycle is unused for a long time. This paper reports on vibration resources detected in a bicycle as a potential energy source for supplying these on-board devices. Measurements showed that the bandwidth of energy vibration is reduced with speed and that the vibrations at any location in the bicycle are nevertheless sufficient for useful vibration harvesting. For this application, a piezoelectric vibration harvester was designed and equipped with a voltage switching interface circuit. Sufficient energy is harvested during the field test.