New Dura Ace R9150 has bought with it Shimano's synchronised shifting... but there's some great news, if you're using previous generation DI2 Dura Ace or current DI2 Ultegra then moving to a new battery & a firmware update is all it takes to open the door to Synchronised Shifting.
So, first up, what is Syncro shift? It's basically the ability to just shift up and down using the rear derailleur only. For each shift the box of tricks instantly works out the front and rear combination to give you the next ratio. To further refine this you can use Shimano's E-Tube Project that is app or website based so you can preset your gear changes.
There's also semi-synchronised shifting. This works by the rear derailleur automatically shifting when you shift the front derailleur to help you keep smooth.
There's also a manual mode that takes you back to how you shift with DI2 Ultegra 6870 and Dura Ace 9070 currently that just provides an automatic trim of the front derailleur to keep things quiet.
Finally, you can switch between these three modes just by double clicking on the junction box switch. Easy.
We've been playing around with some Synchro Shift configuration and we can see a lot of benefits. Synchro Shift can remove the awkward cadence jump when moving between the chainrings if you're on a climb. No more dropping to the small ring and then fumbling to change the cassette to normalise your cadence to comfortable levels. Say your climb flattens off, you just need to move up the cassette until you get high enough and Synchro moves you onto the big chainring.
It'll help anyone looking to keep a nice straight chainline too - we're looking at you time-triallists! No more wasted watts cross-chaining before interrupting your rhythm trying to rectify it. Think about a rolling road race. Your Synchro Shift will allow you to just focus on shifting the rear derailleur and take care of the front. As the road pitches up and turns down, the chainring changes are sorted for you. You just need to keep the power down since Di2 has no problems with shifting under load.
Synchro Shift is like an attentive butler quietly cleaning up your cross-chaining and poor gear selections. Trust it. It'll take care of you so you can get on with the job of riding fast.
To get going with Synchronised Shifting you'll need to grab a new battery, part BT-DN110, that will set you back between $150 and $180 AUD. The new battery has a memory chip that is used to make all the magic happen.
Once you have the battery, you use E-tube software to give your DI2 a firmware update using Shimano's PC diagnostic box, or a Shimano bluetooth wireless unit part EW-WU101 (RRP $139). Or you can, like we fully intend to, go and annoy your local bike shops and get them to do it!