Synchro-Shift - the synchronised operation of the rear derailleur and front derailleur with just one shift lever - was previously only available to road cyclists who had Shimano's new high-end Dura-Ace Di2 R9150 groupset fitted to their bike. Thanks to a firmware update and the installation of the new BT-DN110 Di2 battery, the older Shimano Dura-Ace Di2 9000 and Ultegra Di2 6800 groupsets can now also be retrofitted with Synchro-Shift. The new battery has a memory chip that controls the various shifting modes and customisation options that are possible with Synchro-Shift.
With Synchro-Shift, the rider only has to decide whether to change to a lighter or heavier gear. The rest is done by the electronics, which automatically decide whether the front derailleur or the rear derailleur needs to be activated for the right gear ratio. In addition, the front derailleur automatically recognises the position of the rear derailleur and shifts to the gear with the most favourable chainline. This simplifies the shifting process for the rider. Operation with Synchro-Shift only requires one shift lever, the other becomes obsolete. However, the rider can intervene at any time and shift gears manually as usual in order to outwit the system, so to speak.
Two modes can be set for the Synchro-Shift function. In "Full Synchro-Shift" mode, the front derailleur reacts to the shifting operations that the rider performs on the rear derailleur. Essentially, this means that only one shift lever with two shifters is required to shift the rear derailleur and front derailleur. In "Semi Synchro-Shift" mode, the rear derailleur reacts automatically to gear changes made by the rider on the front derailleur. The rear derailleur automatically performs the necessary equalisation shifts for small jumps in cadence as soon as the front derailleur is shifted up or down.
