We’ve seen and talked about Shimano’s Synchro Shift for both the new R9100 series Dura-Ace and M9000 XTR, where you can essentially program Di2 front & rear derailleur pairs to move in a synchronized manner in response to a single set of shift button inputs instead of separate shifters for each derailleur. While it certainly isn’t for everybody, there are some good rationales to automating the point where the front derailleur shifts to match the position of the chain on the cassette, with any time trial setup coming to mind. Well Shimano realized that they could bring that same functionality to their previous E-Tube based Di2 road groups if riders simply updated to the latest battery that packs the additional processing power required for the automated shifts. So now if you have an Ultegra 6800 or Dura-Ace 9000 Di2 setup, you can get Synchro Shifting by upgrading to the latest internal battery, and updating your groups firmware through the E-Tube app…

The latest Di2 battery that you need is the BT-DN110, which has more memory that the previous generation and can handle the additional processing load & storage needed to manage the multiple shift patterns of Synchro Shift. To get the new functionality allowing Shimano to decide when to match front & rear shifts, users with the new battery and compatible front (FD-6870/FD-9070/FD-9150) & rear (RD-6870/RD-9070/RD-9150) derailleurs just need to upload the latest E-Tube firmware to their battery. You can do that either through the wired connection to your PC or through a Bluetooth connection to the E-Tube App if you already have a wireless controller installed.

Once updated, you can cycle through modes much like you do on the new Dura-Ace with the bar-end button, but with the regular control button on the external junction box under the stem on most Di2 bikes. A new sequence of flashing lights tells you what mode you are in, as you double click to cycle through modes – solid red light indicates manual shift, twice blinking red indicates the 1st Synchro mode, & thrice blinking red indicates a 2nd Synchro mode.

Shifting the rear derailleur from 28T towards 11T, the system recognizes the preferred gear ratio step should be made between the 15T and 17T sprocket. Shifting the rear derailleur from 11T towards 28T, the system recognizes the preferred gear ratio step should be made between the 25T and 21T sprocket.

That would usually mean – Manual, Full Synchro & Semi-Synchro – although you can customize each mode in the E-Tube app as well if you prefer more adjustability of when and how shift synchronization occurs. For a quick refresher, Full Synchro shift allows the rider to only think about shifting up or down and automates the shifting of the front derailleur to stay in an optimal chainring:cassette gearing combination. Semi-Synchro shift makes corrective rear shifts to match your front shifts so you get maintain a smoother transition when you shift the front derailleur and can keep a more consistent cadence.

In either Synchronized Shift mode the rider still maintains control over both derailleurs, and can use the regular buttons to control or correct shifts as needed (assuming you don’t remap shift function away through the App.) Synchro Shift was designed to complement regular Di2 function, and is intended to improve usability when paired with auxiliary sprint, climbing, and time trial shifters.


  1. Chader on

    Please replace all incorrect 6800 & 9000 references (cable/mechanical versions) with the correct 6870 & 9070 references (electronic versions) in the title and content.

    Eds. In fact the 6800 & 9000 numbers are correct as they are the series denoting the generation of products. 6870, 9070, and now R9150 & R9170 are more specific Di2 product numbers, which still fall under the overall Shimano series numbers.

    • Kyle on

      What’s incorrect? The 6870 parts is still 6800 series parts. If the title said “FD-6800” or something to that effect it would be wrong.

      • PabloE432 on

        “In fact the 6800 & 9000 numbers are correct as they are the series denoting the generation of products”

        If you are making specific statements about specific products and their traits, using the series name is incorrect. Ultegra 6800 doesn’t have synchro shift compatibility.

    • Chader on

      Everyone makes mistakes. I suspect this is driven from the MFG notification since I see the same error in the FB post on this topic. Might be misleading text from the origin in this case?

      Eds. Sure, we sometimes make mistakes. This isn’t one of them, though. But you are correct that it results from Shimano referring to their road series by 6800, 9000 & R9100 to delineate one generation of Ultegra & Dura-Ace from the next.

    • David R. on

      No need to wait. Just do it!

      Ultegra synchro shift has been here a while, if you use MTB derailleurs. I set my wife’s touring bike up with 26-36-48 front rings and 11-40 cassette, Ultegra shifters, XTR display, and the MTB water bottle battery case. Works really well with a 7:1 gear range. Also enforces shifting discipline — no cross chaining — without getting into big arguments!

  2. bryan on

    i like the use of the word “thrice” in the article… very classy

    on another note, never having used electronic shifting in my life, could someone please explain something to me- why wouldn’t you want to use this system? it seems like automatically shifting to the next hardest/easiest gear (even if that means changing the big ring) makes the most sense of anything. What is the drawback?

    • Kyle on

      The main one that comes to mind would be sprinting over the top of a climb when you’re in your small ring. If the front shift doesn’t go smoothly under the load it could cause some decent sized problems for you.

      For regular training rides I’m sure it’s perfectly fine. If my bike comes with the new battery I’ll probably use it.

  3. Mayhem on

    Beware Shimano’s (deleted) software, when last attempting a firmware update (two weeks ago) my Dura-Ace 9070 system was bricked. The updater application destroyed the firmware in four out of eight components, including two which were not supposed to be touched as there was no new firmware available. Thankfully a friend had the SM-PCE1 diagnostic tool with which I managed to get everything working again. Shimano really need to hire some better software and QA engineers…

    • Bryan Palmer on

      The potential for this was actually noted in the release notes. It’s even more common on Ultegra. Shimano has recommended mechanics wait to upgrade Ultegra bikes until the next version unless they have the PCE1 available.

  4. Marin on

    Hahaha more processing power in a new battery. What a joke. Like it actually requires significant processing to choose when to shift up or down the front cog.

    It’s just milking money from owners of the new group and planned obsolescence.

    Let’s see what happens to 11s when 12s di2 comes out…

  5. phildurham on

    I purchased a new battery DN110 and the bike shop installed it an updated my firmware. Do I also need the D-Fly attachment to make this work?

    • Cory Benson on

      @Phil, no need for a D-Fly, per se. You can just plug the system directly in with E-Tube for its firmware updates. If your derailleurs are compatible (see above in the article), you can access the new Synchro Shift functionality with the button (& lots of instructive little flashes) on the external junction box strapped under your stem.


COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.