A bicycle electrical system is generally provided with a wireless communication unit, a movable component, an electric actuating unit and a support structure. The wireless communication unit includes a first housing and a wireless communication component arranged in the housing. The electric actuating unit comprises a second housing and an electric actuating device arranged in the second housing. The electric actuating device is configured to actuating the movable component. The second housing is different from the first housing. The support structure supports the wireless communication unit to the bicycle electric system in a dismountable manner.