Bicycle shifting method

A bicycle shifting method suitable for controlling a gear ratio of a front chain ring and a rear chain ring of a bicycle, the bicycle having a front electronic derailleur, a rear electronic derailleur, a controller, and a controlling switch, the controller storing a gear-ratio table, the bicycle shifting method comprising:

• triggering the controlling switch to generate a corresponding signal;
• controlling the front electronic derailleur, the rear electronic derailleur, or both of the front electronic derailleur and the rear electronic derailleur by the controller according to the signal, wherein
• when the signal is a speed-increasing signal, the controller controls the front electronic derailleur, the rear electronic derailleur, or both of the front electronic derailleur and the rear electronic derailleur, so as to increase the gear ratio along a speed-increasing path of the gear-ratio table,
• when the signal is a laborsaving signal, the controller controls the front electronic derailleur, the rear electronic derailleur, or both of the front electronic derailleur and the rear electronic derailleur, so as to decrease the gear ratio along a laborsaving path of the gear-ratio table, and the speed-increasing path is different from the laborsaving path;
• and
• wherein the bicycle has a plurality of the front chain rings and a plurality of the rear chain rings respectively controlled by the front electronic derailleur and the rear electronic derailleur, the bicycle has a chain located on one of the front chain rings and one of the rear chain rings, and the step of controlling the front electronic derailleur, the real electronic derailleur, or both of the front electronic derailleur and the rear electronic derailleur by the controller according to the signal comprises:
• controlling the front electronic derailleur to move the chain from the one of the front chain rings to another one of the front chain rings, controlling the rear electronic derailleur to move the chain from the one of the rear chain rings to another one of the rear chain rings, or simultaneously controlling the front electronic derailleur to move the chain from the one of the front chain rings to another one of the front chain rings and controlling the rear electronic derailleur to move the chain from the one of the rear chain rings to another one of the rear chain rings.