A bicycle electronic system including: a manual command management unit, having a casing configured for being fixed at a handgrip of a bicycle handlebar, that includes at least one first manually actuatable switch and a first processor; a derailleur management unit comprising a second processor; and, a first direct communication channel that connects the first processor and the second processor. In response to the manual actuation of the at least one first switch, the first processor emits a derailleur command signal addressed to the derailleur management unit, and the second processor receives the derailleur command signal from the first processor through the first direct communication channel.