1. Do you know if the brake TT levers ST-R8060-R will work with the bar end shifters SW-R671 please.

    1. Author

      Yes they will work together, but check the Shimano compatibility chart linked in the post above to verify.

      1. Thank you for taking the time to reply.

  2. Hi, I have St-R8050 Shifters, SM EW90-B Di2 Cockpit Junction Box 5-Port, Di2 SM-JC41 Internal Junction Box (4 ports), FD 8050 Front Derailleur, RD 6870 SS Rear Derailleur, Di2 External Battery Mount SM-BMR1-S, Di2 External Battery Mount SM-BMR1-S. and somehow the Shimano E-TUBE doesn’t recognize the battery. It is brand new battery and brand new Battery mount but system can’t recognize them, shows “Unit is not detected”. Any suggestion or recommendation? Thank you so much.

    1. Author

      First, make sure everything has the latest version of firmware. Second, try connecting to just the battery and not everything else, with just 1 wire between the Junction A and the battery.

      1. Hello, Thanks for your reply.
        My current RD-6870 firmware is the newer 3.0 version, That I cant get it working with my old firmware SM-BTMR2 external battery, and ST-R785 shifter. That I have them downgraded to the old 2.5.2 version.
        However, I cant find any RD-6870 related file in the FW folder. Could you help to share that older version? Or is it using other file name in the FW folder. Thx

        1. Author

          Sorry, I’m not sure where to find that file. I only have the 2.5.2 software install package, not the individual firmware files.

          1. Hello, I have the eTube 2.5.2 version installed. But the SM-BTR2 firmware version is SMBMR2.2.3.1.
            My 6770 groupset is not working with my RD-6870 rear derailleur.
            Could help to inform where can I find the SM-BTR2 BATTERY FIRMWARE AT V2.0.6 OR EARLIER?

  3. Hey,

    I’m new to the whole di2 concept and getting lost in a maze of serial numbers online. I’m looking at getting my first triathlon and because where I live is quite hilly I like to have a certain setup with the shifters that I’m not sure is possible. Ideally, I would like 6 shifter buttons, dual buttons on the tt bars to control both the front and rear mech, and then shifters on the breaks to control the rear mech (or the other way round). I know Syncro shift would probably work for what I want but I’d like the ability to be able to drop the front mech when going from fast flat to a steep incline.

    So basically, I think my question is. Is it possible to have 6 different shifters on a tt bike and how what would the setup/junction boxes look like?


    1. Author

      JR, this the standard triathlon/time trial setup. There is no limit to the number of shift buttons. You need a left/right SW-R671 Dura-Ace 2-Button Time Trial/Triathlon Bar End Shifters (or similar), left/right ST-6871 Ultegra Time Trial/Triathlon Dual Control Brake Levers/Shifters (or similar), and a 5-port SM-EW90-B 5-port Front “A” Junction (or similar.)

  4. Hello, i have a bike with an older 6770 kit, that comes with an external battery.. It’s a second hand bike and didn’t come the charger. If i updated junction block a to the latest version that has the pc link and and charge port, would it be possible the use the latest charger to charge this battery? Or do i need to get the external battery charger. Thanks

    1. Author

      Al, you have to use the external battery charger for the external battery. Only the internal battery can be charged via the the newer A junction charging port.

    2. Hi Al, If your interested I have a spare charger for the external battery including a spare battery. Let me know if you are interested. I am living in the Netherlands.

      1. Thanks for the offer Jos, I am in the states so shipping may be a bit much. I’m considering just biting the bullet and updating to the newer battery with the associated hardware.

        1. Thanks for your reaction. One of the nice features of the new internal battery is Synchro-shifting. I am very pleased with it.
          Succes upgrading your bike.

          1. Hello Jos are you using a 6770 group with synchro shift? I searched and looks like i can’t use it for my group unless i do more upgrades 🙁 i may have to consider your offer

          2. I am using the 6870 11 speed front and rear derailleur.


  5. Hello Carlton…Thanks for your thorough and detailed summary. I have a Trek Domane SL road bike with a Shimano Di2 setup. I also have a Garmin Edge 810 computer. The Edge provides the option of displaying the Di2 Battery Life while I’m riding and I’d like to know that although it’s not critical. I’m also interested in the synchronized shifting, especially when I down shift from the big ring to the smaller ring, I’d like the rear derailleur to go up two gears, a fairly common option.

    My questions are: What additional components are needed to enable the Di2 to communicate with my Edge? I believe I will need the DN110 internal battery and the EW-WU101 and EW-WU111 ANT and Bluetooth Wireless Broadcast Modules. Is this correct? What is the difference between the WU1010 and WU111? Do I need both? Any cables? Assuming I installed this, or had it installed, will I need to use the E-Tube Project software to program the shifting?

    Thanks for your help.

    Regards, -Burton

    1. Author

      Burton, you are correct, you will need the DN110 internal battery and either the EW-WU101 or the EW-WU111 Bluetooth/Ant module. The two modules are identical in functionality; the only difference is the shape. You will most likely need on additional eTube wire to place either module inline. (You could install the SM-EWW01 ANT-only Wireless Broadcast Module if you just want Garmin gear selection display but need the new battery for SyncroShift.)

      For SyncroShift, you’ll need a 6870 or newer derailleurs and the DN110 internal battery.

      You’ll need the Windows eTube software to update the firmware after installing the new components, to enable/configure SyncroShift, and to enter gear ratios.

      1. Thanks Carlton. Appreciate the update. Seems like a lot of time, money and effort. For now I’ll pass. Appreciate the education.

  6. Hi Carlton, I have a 6870 series (Groupset) 11 speed Di2 setup that has the external SM-BTR1 battery and SM-EW67 A-E junction. I just upgraded my RD to the XT M8050 to allow a 11-34 cassette. I am told the firmware needs to be updated as evidenced by the new 8050 does not work while plugged in, and the FD now fails to function. I purchased a EW-WU111 to assist me in the firmware updates and other bluetooth functions. I just read the SM-EW67-A-E is not compatible with the EW-WU111. I prefer to not upgrade the battery to a BT DN110. Is there a better was to:
    1. Achieve firmware updates?
    2. Achieve Gear display and battery % on my 510 Garmin via another wireless D-fly system?
    3. Can a SM-EW90 work with the SM-BTR1 battery?


    1. The DN-100 external battery holder has the memory function to work with the EW-WU111 Bluetooth.
      Avoid doing firmware upgrades via Bluetooth. You run a very high risk of bricking the system and will then need the PCE unit to restore any Di2 functionality. Typically a decent bike shop will have one of these.
      Just use the Bluetooth for setting changes, such as Synchro.

    2. Author

      Kevin, you’ll need to update the firmware on everything using the Windows eTube software and PC adapter. The Bluetooth module won’t work until you update all other firmware first. As mentioned, you probably should do future firmware updates via Bluetooth due to higher possibility of failure.

      Yes, the SM-EW90 will work with the SM-BTR1 but it won’t charge it.

      You can achieve Garmin gear selection display via the Bluetooth/Ant+ modules or the Ant module alone. For Bluetooth phone settings support, you will need the DN110 internal battery (or the new external battery) and either the EW-WU101 or the EW-WU111 Bluetooth/Ant module. The two modules are identical in functionality; the only difference is the shape. You will most likely need on additional eTube wire to place either module inline. You could install the SM-EWW01 ANT-only Wireless Broadcast Module if you just want Garmin gear selection display – it does not have Bluetooth and does not require the newer battery.

      1. Thank you Carlton for your advice. I am now looking at installing the SM-BTR2 with the SM-EW90-A to function with the EW-WU111. I will also pickup the SM-BCR2 charger with USB PC adapter to update the firmware to correct the current non-function/compatibility between the FD 6870 and the new XT M8050 RD. Hopefully this plan is sound.
        Thank you again.

  7. Hi Carlton, I am currently using DA 9100 on a Tri bike. I have the 9160 switches on the extensions, and 9180 shifter/hyd brake levers. My question is, can I use the 9150 climbing switches to work in conjunction with the 9160s to shift the rear derailleur, and program the 9180s to shift the front derailleur? Anything I need beyond wires or junctions? Thank you in advance.

    1. Author

      Bill, this setup should work fine as long as you add enough junctions and wires. You can configure all of the buttons using the Shimano eTube software.

  8. Hi Carlton, Can a BMR1 charger and the mount for external batteries be used for the SM-BMR2? And does the SM-BM DN100 used the same charger as the BMR1 and hardware or another set of components? Thank you.

    1. Author

      Kevin, I believe the batteries themselves are interchangeable but you will not get features of the newer firmware. But everything must be updated to the latest firmware version. I have not done this myself, so hopefully someone else can confirm.

  9. Hi! I have 6770 sti levers and front derailleur and a SM-EW67-A-E. They are not updated beyond 2.5.2 firmware.

    I must buy a RD and battery mount( already have external battery). I’m thinking about getting a rd-6870, as my parts isn’t updated it should work with 11-speed.

    Does it matter if I buy SM-BMR1 or SM-BMR2 (new from retailer), is there a risk that they will be updated beyond 2.5.2 and thereby making mixing 10 and 11 speed derailleurs impossible?

    1. Author

      You will almost definitely need to update everything to the latest firmware to get the new parts to work. They will come with the latest firmware. My recommendation is that if you want to update to 11-speed, upgrade both derailleurs.

      1. I have now got my system working with 11-speed using:
        SM-EW67-A-E. ST-6770, FD-6770, RD-6870 and SM-BMR2
        I have upgraded (and in some cases downgraded) firmware to e-tube 2.5.2 using SM-PCE02. No problems with this setup.

        Warning! I first used a SM-BMR1 battery mount and only the front derailleur worked. It could not be updated using the SM-PCE02. E-tube could not find the SM-BMR1. I suspect that to update the SM-BMR1 you need the Sm-PCE1. I bought a SM-BMR2 and had no problem updating that using the SM-PCE02.

        1. Hi, Martin, could you inform which firmware file did you used, on updating the RD6870? I cant locate a 6870 named dat file in the FW folder, in 2.5.2 firmware folder.
          Please help. THX

  10. I installed SW-R671 into my Di2 6870 road bike. It’s shifting okay but my etube does not recognize my SW-R671. What shall I do to make it recognize?

    1. Re: steps #3 & 4 on adjusting rear derailleur trim-are you saying push the lever that normally moves the chain to a higher gear & use it to move the chain toward the 4th cog. Then after you hear it rub, hit the other lever 4 times. The 4 times -does it calibrate or realign and make the shifting all fixed? I am struggling, my shifting is off & when I fix one area on the back cogs, another area starts messing up. Thanks for any help.

  11. I have a 9070 Dura Ace full groupset. My question is can I install or add wifi cable to make it wifi capable? Because I brought it to my local bikeshop and they said it is not possible due to compatibility issue of 9070 rear deraileur. But before I guve up, I still want your oppinion and knowledge on di2’s specifically on this issue.



    1. Author

      Carl, I assume you mean Bluetooth and not WiFi (there is no WiFi module.) If you have the newest battery, you can use the Bluetooth module. All of the details are in the article above and have been discussed recently in the comments.

    2. Hi Carlton, I have a dura ace 7970 tt system which has developed a fault. The rear derailleur changes through all the gears on one press of a shifter button ( up or down). It would also seem it shifts more times than it should followed by a lot of clicking. Can these derailleurs be reset or am I looking at a new system.

      1. Author

        It could be that there is an issue with your shifter button or wiring, but it’s more likely that the derailleur is the issue. A used replacement part off ebay would be the potential cheap solution. But a full upgrade may be the best bet.

  12. Hi, my bike is equipped with Di2 9150 and the battery is constantly discharging. The bike shop I purchased the bike from have replaced two batteries and all the wires and the problem continues to persist. Currently the battery life is less than 6 hours after a full charge.
    Note, the bike is still just over 12mths old and I known Shimano warrants these components for two years. The shop have been great support but the problem is beyond frustrating. I suspect it is the front derailleur..?

    What are your thoughts?

    1. Author

      It’s hard to say it’s the front derailleur for certain, but at this point, the bike shop should start swapping parts to make the problem go away. That is crazy low battery life. I’m assuming they have made sure everything has the latest firmware version. It should be possible to measure current draw on the batter with a multi-meter; there should be a drop in current draw when the offending component is disconnected. You will need to sacrifice a Di2 wire (cut one of the leads and place multi-meter in series) to measure the current draw from the system battery. https://youtu.be/7lwZkl0yBqA?t=94

  13. I have one of these leads. I had a Fluke DMM connected in series with it, it did not read great, and it effected the calibration of the rear derailliuer. I then used a clamp on mA meter and this worked fine. I found my rear derailliuer was drawing 2.0mA . Changed the derailliuer and all ok since. You could always check the voltage drop twice a day for a few days, this will point you to the faulty item. Firstly disconnect the rd, then the fd. As your battery is dropping quickly, it should be fast to pin point the problem. Mine was not and it looked like a battery problem .

    1. Hi, just some feedback I have tried the basics and disconnected the front and rear derailleur and the fault tends lead to the front unit. What I have also noticed the battery discharges quickly when the system is in semi or auto mode which again makes no sense..? As previously mentioned, the bike shop has replaced all the wiring and charging unit but the problem still persists. After a full charge, I have done just over 100kms and my battery power is on 70% and this is when the power discharges rapidly after each use.

  14. Hi, hope you can give me some guidance here. When I charge my Di2 it lasts less than 4 rides (30/40 miles each) and 2 weeks. I charge following your recommendation until lights turns off. I noticed that when I “test” the battery it shows green and 3 seconds after it shows green and red together.
    What do you recommend me doing? Something is not working well because I read it should last at least 1000 miles or so.

    Thanks in advance!

    1. Any recommendation to my question Carlton? Have you seen that before?

    2. Author

      Eduardo, your battery might be bad. But it’s more like that one of your derailleurs is bad and is continuously pulling power. Trial-and-error is the only way to figure out which component it is. Read through the recent comments on this post for others who have experienced the same problem.

  15. What about changing a older sm-btr1 to the btr2 so I can get synchronized shifting what’s the process? Tried looking online but really can’t find anything. I know firmware but will the battery just plug in with the same connector?

    1. you need the DN-110 battery for synchronised shifting. BTR-1 and BTR-2 do not have the memory function to support synchro.

  16. My bike has ultegra Di2 6770 system, may I ask can I replace the RD 6770 by Dura Ace RD 9070? Thank you.

    1. Author

      No,both the front and rear derailleurs need to both be 11-speed (or both 10-speed). Upgrade both front and rear, or get a new rear to match the front.

  17. Hi Mr Bale. Do you know if is possible I become a 7970 di2 10v road groupset to 11v speed only changing the rear derailleur to 11v (like a 6870 or 9070 for example)? thank you

    1. Author

      Cesar, this conversion is not possible. 7970 components are not compatible with anything else. Full details are in the article above.

    2. Dura-Ace 7970 10s is completely incompatible with any of the 11 speed E-TUBE system.

      If you want an 11 speed setup you will need a completely new 11s group

  18. Hi and thank for an extremely informative page!
    I have a system with st6770, sm-bmr1, sm-ew67 and I’m changing from 10 to 11-speed derailleurs. To do this I have updated firmware using sm-pce02.

    The update process work well for all parts but the sm-bmr1. E-tube can not find it and I get a message saying I need a sm-bcr1/sm-bcr2/sm-btr2 for the system to work.

    Shifting works like normal when using the old 10-speed derailleurs.

    Any Ideas how to get e-tube software to find and update the sm-bmr1?

    1. Now I also tried clicking on the “cable icon” in e-tube and connect just the sm-bmr1 but with the same result. Hm….

      1. It was my understanding that 10 and 11 speed won’t work together with the latest firmware and this needed rolling back, your 11 speed rear will undoubtedly have the latest firmware? I presume you’ve used the sm-bcr02 to plug into the sm-bmr1 via the etube cable?
        The article also states that

          1. I have now solved the problem. It seams that the sm-bmr1 cant be updated with the sm-pce02. I got a SM-BMR2 instead. Updated it and everything works ok.

  19. Hi
    I tried to run an update on 6670 groupset. During the uptate it failed and now e-tupe wont reconize the left lever. I have tried to connect in both ports in the lever on its own, and also via other components. But it do not appear 🙁 Is there a solution, or do I need to get a new left hand lever 🙁
    Thanks in advanced

    1. Sorry its a 6770-L lever and groupset of course

      1. You should be able to re-flash the firmware to the shifter using a PCE1 adapter. That’s what I would try first.

  20. Is there any documentation of the overall protocol used on the e-tube bus for the STEPS systems, specifically the D5000 gear? I assume it’s the same for the D6000 etc. I have seen comments on some forums that suggest it’s encrypted.

    1. Author

      I’ve never seen it fully documented, but it’s a standard CAN protocol and it’s not encrypted. You can attach an oscilloscope to the harness and read the commands. The most common commands are right shifter upshift/downshift and left shifter upshift/downshift that are sent when activating the shifters.

      1. I have put an oscilloscope on the wires. 30 years ago I was an oscilloscope ace, but clearly not now. There are only 2 wires, power & “ground”, the signal is modulated onto the power wire, and we were not able to see any distinguishable patterns with the different shifter commands. We saw movement. We were using a scope without any additional bus protocol software. Then Shimano came out with syncro-shift and I stopped investigating. And I never added syncro-shift anyway.

        1. Once the lever is pressed the voltage rises by, I think 0.3 to 0.5 volts on the wire. This is not from the derailliuers because with both plugged out, the voltage still increased with the lever pressed. This test was done with 2015 year battery on a 6870 system.

  21. Hi Carlton

    first thank you for your site and info on DI2. it has been very helpful and informative.

    i have a question:
    have you ever dealt with an error message in etube saying there was an issue connecting to the PCE-02? And that if the problem persists it could be a faulty PCE-02?
    i was trying to revert my firmware to mix and match RD-6870 and FD-6770. Halfway through the process (i believe when i was updating the battery to the “new version”) it gave me the fault, and now i can’t even connect

    any thoughts?

    thank you very much for your time

    1. Author

      I’ve never heard of this before. I’d be surprised if there was a hardware failure during the update. It seems more likely that there is a PC software problem. I’d try uninstalling and reinstalling everything.

      1. Hi Carlton, so I figured out it was the battery mount, SM-BMR2, that is causing the “faulty PCE-02” message.
        So, i ordered a new one, and now the PCE-02 wont even recognize the SM-BMR2. It goes through the process of trying to recognize the device, then just goes back to the home page of e tube. THis happens both when i connect to the whole system through the shifter or directly to the battery mount (with and without battery installed).

        I read online thaat someone only was able to resolve this by finding someone with a PCE01 and having them update it as the PCE02 sometimes has issues. I dont think i have this option.

        Would you happen to have any suggestions?
        Again, thank you for your time


        1. Hey Dex,

          I think that is the case for the SM-BMR1 only, but I’m not 100% sure on that..
          My suggestion would be to phone a couple of bike shops and ask them to check it with their SM-PCE1 – most of them should still have that.

  22. Hi Carlton,

    I’m running Ultegra Di2 6870 and I’m finding the rear shifting not smooth under load when it’s on my Tacx Neo Turbo trainer. I’m not getting hesitation or any clicking but it’s changing quite abruptly and interrupting my pedal stroke. There’s also quite a ping when it changes gear under load. I think all the limit screws are set OK – it’s shifting into all gears and no noise when it’s in a gear. I tried a spare cassette to rule out the cassette and same issue with both cassettes I tried. I’m at a bit of a loss with why it won’t shift smoothly when under load. Any suggestions please?



    1. Hi, I had the same problem with my Tacx Neo and my Trek Madone with Shimano Di2 6870. It turned out that the cassette hub was placed too close to the flywheel of the /tacx. Through the Tacx website I ordered a spacer which I placed on the Tacx Neo. Instructions can be found on the Tacx website. Hopefully this will solve your problem.

      1. Thanks Jos.
        Struggling to find what you refer to on Tacx website. Do you have a link?

        1. Here https://tacx.com/nl/spare-parts/neo-smart-nl/ you can buy the S2800.01 sparepart set. containing following parts.

          Ouick release, rear wheel (1)
          Spacer 5mm for discbrake (1)
          Free hub body spacer 1mm (1)
          Free hub body spacer 0.5mm (1)
          Fill ring Shimano 10 speed (1)

          When you dissaassemble the cassette you find a little black tube. Remove that tube and then place T2805.11 or T2805.12. Then place the black tube back and then your cassette. It’s a matter off trial and error. I hope this will solve your problem.

  23. I have a 5 or 6 year old 11 speed road di2 setup, mostly Dura-Ace but the rear derailleur is the wider range Ultegra. In the past few months the system has started to forget the rear derailleur adjustment settings. Originally it seemed to happen only when charging the battery, but it has progressed to happening while riding at 30F. Is the adjustment memory in the derailleur or in the battery? My guess is rear derailleur because the front appears to be fine, but I seldom shift the front.

    1. Author

      I would assume that the setting is stored in the rear derailleur itself, but I can’t say for certain. My guess is that your rear derailleur is starting to fail and that is causing the problem. I’m not sure if it’s a mechanical or electronic failure, but either way, trying a replacement derailleur is probably your best best.

  24. This problem has been with one of the Di2 bikes in the family.On the big ring I cant shift onto the smallest sprocket. Can move onto the largest sprocket. On the biggest sprocket tube shows that the chain is on spokes 2 when in fact its on 1. Using custom shifting one tube it’s impossible to show the chain on the correct sprocket ie No2. This logically explains the inability to get the mech to move onto the number 11 sprocket. How can I make tube recognise the correct chain position?

    1. Author

      This is not a software problem. This is a physical alignment problem. You probably need to adjust the limit screws on the rear derailleur. And then recalibrate the trim via eTube after getting the limit screws adjusted properly. Instructions for doing this are in the Shimano installation instructions. There is a link in the article above (or do a Google search.)

      1. Yes software I suppose. I cured it by backing off both limit screws – the high limit screw was well baked out in fact. Then moved setting to manual and was then able to move the chain onto the smallest sprocket. . Still on manual onto largest sprocket, now into adjustment mode to adjust the rear mech to correct changing between sprockets. Seems ok now and E-TUBE shows the correct actual sprocket selected.

        1. Hi There – a new question. I’m in the middle of converting an old bike (without internal cable routing) to Di2. Would you happen to know if an SMBTC1 (and BT DN110) can be used instead of BM DN100 (plus SM BTR1) plus SM JC40

          1. Author

            There should be no issues with using the external battery mount with the BT DN110 Battery. (I would personally use that instated of the other external battery mount.)

          2. Just by way of an update I have now assembled externally routed cables with the BTC1 and BT DN110 – it works perfectly and in my opinion results in a much neater and better integrated solution that the old style battery mounts

  25. About Short bottle cage battery mount, SM-BMR1 and SM-BMR2
    Would you have any idea for a short length external battery mount, to be placed under the existing bottle cage closer to the BB?
    Is there any rod or extension mount could be used to adapted to perform like a long length mount?

  26. Hi Carlton. I have 7970 Dura Ace Di2 on my trusty 2010 Felt Z2 which i love. The gears have recently gone on the blink and even after buying a new battery it still discharges quickly even when not riding. I read in a previous post that possibly either the FD or RD is continuously pulling power. Is there anything i can do if that is the case?

    1. Author

      James, the first thing to check would be the wiring. Make sure that there are no shorts between any of the cables. But my guess is that it’s probably one of your derailleurs. Disconnect the front and see if there is still battery drain. Then do the same with the rear. Ebay.com is probably the best place to find replacement parts. If it’s in your budget, upgrading to one of the latest Di2 systems would probably be worth it.

      1. I had two issues, both were battery drains. The first I thought it was the cold garage that was draining the battery, changed the 5volt charger and all ok since, that was four years ago. Then three years ago the same thing happened. Traced it to the rd drawing 2mA constantly. I had a rd and changed it. Things gmhave been perfect since……some day, I might just plug the cable into the old rd and see if the fault is still there.

        1. Thanks Kevin. I was hoping that if i left my bike alone for a while it might miraculously repair itself! Sadly hasn’t.
          I’m going to test whether i might have the same problem as you. I’m on my second rd after a crash. They’re not cheap!

          1. Hi James, I had a cable that I cut and measured the voltage level. I also measured the current with a meter inline was not great and it put the rd out of calibration. I used a small clamp on DC ammeter and this was ok. But if you have none of these, time is another tool. See how long it takes to discharge with everything connected. Then disconnect the rd and see if the battery lasts beyond the time with everything connected. ..The faulty rd I had, still changed gears, but was draining.

          2. I have successfully combined 2 broken rear derailleurs into one working rear derailleur. Maybe you can fix the crash-damaged derailleur with parts from the one with broken electronics. Or vice versa.

          3. Hi James I was looking for a screwdriver to open the locking screws they use, but have not found one yet, that would be the next move. That would allow one to swap the motor out.

      2. Thank you Carlton. I did buy a diagnostic tool and know that both derailleurs work but i didn’t wait to see if one was draining the battery. i also bought a new battery and Junction A as the latter didn’t seem to be signalling the battery level at all. I also checked out upgrading to a later system but i believe that as the bike is old i am limited to which series will fit.

        1. Author

          James, you should be able to upgrade to a newer Di2 version, but you probably will need a new rear wheel and sprockets (to go from 10-speed to 11- or 12-speed.) You should not have to upgrade your front rings or crank if you to an 11-speed system, though I think the 12-speed system has a narrower chain that may require replacing the front rings. All new cables will also need to be run. It’s a major undertaking and not for the faint of heart. Identifying and replacing just the component that has failed is your best bet.

          1. That job is well above my pay grade Christian. I have taken the bike into a few good bike shops but to be honest they’re not really interested in seeing if it can be fixed.
            I will test the RDs as you suggested first i think but many thanks for the advice. I really appreciate it.

          2. so i fully charged the battery, unplugged the rear derailleur and waited to see if the battery discharged. It did in two days! Thought that was my issue until i recharged the battery, plugged in the rear and unplugged the front. Rear doesn’t work at all.
            Think i need new gears!!

  27. Hi Carlton. I’m building a new bike with DA9150. my RD-R9150 and FD-R9150 have been shipped and are somewhere in the world right now. i thought i could use an RD-9070 and a FD-9070 temporarily. I’ve upgraded the firmware to the latest but there’s no response from either FD or RD.
    are there compatibility issues?

    1. Author

      I don’t have direct experience with 9150. I’m not aware of any protocol changes that would make your setup incompatible. It theoretically should work. Perhaps the issue is the computability updates are not out yet for newer components?

  28. Great site! I run DI2 with XTR RD-M9050 rear, FD-M9070 front, and a SC-M9051 display, I am running full syncro shifting. Not sure if it is a programming issue or what, but it is programmed to move up one gear in back when dropping down into the small front ring. About 10 percent of the time it only up-shifts the rear no downshift up front, it may or may not downshift the front after maybe 10 seconds. I have not been able to duplicate this on a bike stand but it is devastating on a ride. Battery is fully charged any ideas?

    1. Author

      My guess is that it’s a mechanical problem and not electronic. Try readjusting the set screws and front derailleur positioning.

  29. Hi, I have an early di2 set up Ultegra 6770 with SM-EW67-A-E Ultegra 3-Cable Junction, I find some people can not resist playing with the paddles, as there is no off switch I can come back from work and find things not right so to speak, how can I add a hidden off button so nothing works at all till I switch it all back on? as for where IO hide it I have lots of options I just want to know how to do it without causing damage to the system.

    1. Just disconnect a wire to the battery. Just remember to reconect before you ride off. Easier obviously with external battery vs innternal

    2. Author

      I agree that unplugging one of the cables is the easy solution. But it is a bit difficult to plug and unplug the cables – they are designed to not come out of the connector accidentally (and are difficult to reinstall.) Shimano has an Etube connector tool that makes this much easier.

      If you want to install a switch, it’s simple to wire. Di2 is a 2-wire system. Splice into the wire going from the front junction to the rear junction, or from the rear junction to the battery. When the switch is “open/off”, there will be circuit will be open, and communications and power will not work. When the switch is “closed/on” it will function normally. I would put the switch in the ground wire, but it doesn’t really matter which of the two you pick. Cutting the wire and splicing/waterproofing the will be the most difficult part. I recommend adding an additional cable (with inline switch) and a SM-JC41 Junction to your existing install instead of cutting/splicing an existing already-installed wire.

      1. I was hoping to avoid splicing wires, so untidy, I will take a look at the problem now I know I can disrupt power without damaging the system, I will probably just remove the battery for now but putting a switch into the earth line looks promising, if someone has a destroyed di2 brake lever I can buy cheap to rob of parts to make a plug in diversion I would appreciate it. G J Power
        – email is powerclocks at hotmail (dot com).

        1. I am looking into your idea with the SM-JC41 plug, I will have a chat with my local mechanic and see what he has in his box of tricks, one other question, I want to add wireless EW-WU111, I was going to put it before the bottom junction box inside the frame before I get my local mechanic to tune the system so he could set it up properly, he has said don’t do it, it could cause unexpected problems with the shifters, am I going to the wrong mechanic?

        2. Author

          That’s how I’ve had my wireless module mounted for years without issue.

          Each additional connector you add to the system slightly increases the risk of some type failure, but not significantly. I wouldn’t worry about mounting it there.

  30. My legacy Dura-Ace 7970 groupset came with a BTR1 and BMR1. I’ve just purchased an FD9070, RD6870, EW67A-E, and a JC-40 to upgrade to an 11 speed setup. Will I need to replace the BMR1? Thinking that the E2 cables won’t be accommodated because the BMR1 currently uses the 5-port cables. Thanks in advance for your reply.

    1. Author

      Nothing is compatible between the 2 systems. You’ll need to purchase all new cables.

  31. Thank you for a great article. My TT bike has a 10 speed 7970, which is not working well after crash. Unfortunately, it is not possible to get a new derailleur. On ebay I found 10speed 6770, which I am considering to buy, but based on your article 7970 cannot be replaced by any other derialleur. Is that right? What would you recommend me to do to get my bike functioning? Thank you very much for advise! Tomas

    1. Author

      Tomas, you are correct, you cannot use 6770 components with 7970. The cheapest solution is to create a search notification on eBay and wait for the part you need to be listed. If you have the budget, replacing everything with a more modern system is a worthwhile investment. You may need a different rear wheel/hub to go to 11-speed or 12-speed. That’s the route I’d take.

  32. Hi, I have been here asking questions previously and have a new inquiry, I have had my Ultegra Di2 10sp set up for me at the local bike store but there was a problem and it will not go to the large cluster, I am told the derailleur is badly worn and the slack in the derailleur itself is the problem, I can accept that as it does feel loose, are these repairable, I thought I would ask before I started down the track of removal and attempting repair. perhaps I should be looking for a better one or a damaged one for parts?

  33. Do you know if the internal junction box can be replaced by a diy harness cable?

    1. Author

      Yes, it’s just 2 wires inside each cable. Connect them in parallel and it will work the same. There are no electronics in the internal junctions.

    1. Author

      If it was working properly and now it’s stopped working, then it’s probably a failed rear derailleur. You need to replace the derailleur.

  34. I had a road bike with Di2 set up and working perfectly. I decided to switch to a different bike, bought a new frame and paid a mechanic to move everything from the old frame to the new frame. Now the wireless connection to my Garmin is not working. The mechanic left for vacation right after I picked up my bike and won’t be back for a week. I tried pairing the Garmin with the wireless unit based on the existing sensor stored in my Garmin multiple times, then removed it from the Garmin screen and tried discovering it, but no success. The Garmin is still working with the wireless Di2 on a different bike, so it’s not the head unit. I plugged the problem bike into my Windows laptop and the E-Tube software lists the charging port/junction box, the battery, both derailleurs, and both shifters on the left side of the screen that has the inventory. It does not list the wireless unit. In the diagram, it shows the above components and has a row in the table for “wireless” which (strangely) says “1 units from this group” but no model number, the right column of the table is blank (unlike the other rows which have the model number for each device). Does that indicate the wireless unit is plugged in and not recognized? Or is it missing or not plugged in all the way? If I could diagnose and resolve this myself, I’d like to, I don’t really want to wait for him to get back. Thank you!

    1. Author

      It’s hard to tell what’s going on here, but it sounds like maybe the Ant+ unit isn’t plugged in. You definitely need to check to make sure it’s there and connected properly. There’s also the possibility that there was a failed firmware update by the mechanic? This is just a guess, but something to consider.

  35. Hi Carlton. Great site. I have an Ultegra DI2 setup on my Trek Domane. FD-R8050. RD-R8050. BT-DN110-A. SM-EW90-A. EW-WU111 BT Module. When I connect to the eTube mobile app I can NOT select my 11-34 cassette (only 11-28 or 11-30) . my Trek shop did upgrades to firmware last week and the mobile app says all components have “latest” firmware. Is there a way to add the 11-34 cassette? I like the Gear display it creates on my Garmin 1030 but I would like it to be accurate. Y
    Thanks again for great site…

    1. Author

      I think the issue you are having is because you have the SS short cage length rear derailleur. Shimano requires the GS medium cage length version for official compatibility with an 11-34T cassette. In my experience, the short cage derailleur generally will work with 11-34 cassettes, but it is not something officially supported by Shimano. You’ll need to get a RD-R8050 GS (medium cage length) derailleur for that 11-34T gearing option to become available in the eTube app.

      Cage Length [SS] short, [GS] medium
      Capacity [SS] 33T, [GS] 37T
      Cassette Range [SS] 11-30T, [GS] 11-34T

      1. Does the rear derailleur have different programs for the different cassettes? I had always assumed not, but it is a possible tuning parameter that Shimano could have chosen to implement.

        1. Author

          The rear derailleur isn’t calibrated specifically to the gear diameters/ratios. It moves a fixed distance side to side, regardless of sprocket sizes. The only time the rear gearing is a factor is SyncroShift coordination between the front and rear derailleur. For SyncroShift to work properly, the front derailleur will move down to the smaller sprocket and the rear will move up a few positions to a larger sprocket. The resulting gear ratio should be one step “easier” than the previous gearing combination. To calculate this properly, the Di2 controller needs to know your front/rear gear ratios and when/how many gears to skip during front/rear combo SyncroShift to give the next appropriate ratio.

          For SyncroShift to work properly on your bike, you either need to use a supported rear sprocket size, switch to a GS long-cage derailleur, or just deal with SyncroShift not working perfectly (or disable it completely.)

          1. Does eTube show the option of a larger than 28 rear cassette if you have what Shimano thinks is a compatible rear derailleur? I run a rear 32 with my DuraAce short cage setup and it works with synchroshift but of course only shows the 28 on eTube. It shifts well but I guess the combination after synchroshift isn’t optimal. Nevertheless it seems OK. Also, my frame builder said the DuraAce short cage rear derailleur working well with a 32 depends on the dropout. Mine works great with the 32.

          2. Author

            eTube will show a different (approved) cassette range for the short cage vs. the medium cage derailleurs. eTube won’t let you manually specify anything other than their approved sprocket sizes…because that’s the Shimano way.

          3. Can one use a newer Ultegra 8050 GS rear derailleur in an otherwise Dura Ace 9070 setup to get that extra cassette capacity? Are the shifters compatible between these generations and will eTube be OK with it?

  36. Hi Carlton, Thank you for the years of advice and information. My question today is: Can I disconnect my front derailleur from the DI2 system without causing havoc? I plan on racing an IM (flat course), using only the 39t chainring (39-53t), and I figured why have the extra hardware, if not needed. Thank you.

    1. Author

      Yes, you can disconnect and remove the front derailleur without issue and the rear will still work. These 1x setups are becoming more popular, especially with wide ratio 12-sprocket rears becoming common.

  37. Hi Carlton,
    Can I use an Ultegra Di2 8050-GS mid cage rear derailleur with my Di2 Dura Ace 9070 setup to get extra cassette capacity?
    thank you in advance

    1. Author

      You have to upgrade both the front derailer and the rear derailer if you want to change to a different cassette capacity (10 to 11, 11 to 12, etc.)

      1. I think the OP just meant a wider range cassette with the same gear count.

        1. Yes I am only talking about a changing cassetteto a wider gear capacity (max 28 to max 34) but still keep 11 speed system.

          1. Author

            Thanks for the clarification. I should have looked closer at the part numbers. Yes, you can change from an 11-speed short-cage to an 11-speed GS long cage rear derailleur without changing anything else. This will give you compatibility with a 34T cassette (the short cage only supports up to 30T.) You may need to update everything to the latest firmware to get it to work.

          2. FYI: I have been using a 11-40 Shimano MTB cassette with the Ultegra Di2 8050-GS mid cage rear derailleur and 50/34 on the front. Two extra links in the chain. I am using synchronized shifting just to make sure I will not go big/big.

          3. Author

            This is good information. In my experience, all the Shimano rear derailleurs work with larger cassettes than what Shimano officially supports. Shimano just wants to rule out any possibility of an issue, so their recommendations are very conservative.

          4. I have been using 46-26 chainrings on my Di2 setup for 5 or 6 years. Shifting is acceptable but not great.

            And if I knew how to reply to Bob Goodman, the single button TT 11 speed shifters are apparently software upgradeable to 12 speed. Unfortunately the R671 2 button tt shifter is not listed and that is how my main EPS conversion shifters are constructed. I do not own any single button shifters, but it appears that the R671, the corresponding tt brake lever shifters, and the standard road bike 11 speed shifters all use the same circuit board, with some manufacturing option to tell the system what it is. For example, the system knows that I have 3 R671 shifters on my bike, the 2 boards in the EPS shifters and the one actual R671 on the aero bar.

            I read somewhere that the 12 speed di2 cable brake shifters are reworked 11 speed shifters, and they are wired into the battery instead of being the new wireless. I have not bought those either (or any other Di2 12 speed stuff) so I do not know.

            Time to get a job with Shimano on the Di2 software team to make my own bootleg 12 speed setups.

          5. Guys,
            I have been running an 11-36t cassette for ages now and it works perfectly.
            Some hangers MAY need to use an additional extender like the Wolftooth but many don’t.
            That larger ring is fantastic on those big hills.

      2. Are the 11 speed shifters compatible with 12 speed? The compatibility charts imply that they are not. It would be nice if they were, because then my EPS shifters converted to di2 would still work.

        1. Author

          As far as I know, all shifters work across all 10-speed/11-speed wired setups. They all send the same simple “gear up” or “gear down” commands. Wireless (semi-wireless…no wire between shifters and derailleurs) is a different story.

          1. You can’t use older 11 speed shimano di2 shifters with the newer shimano 12 speed system. They are quite different, including the semi wireless capability of the shimano 12 speed di2 system components

        2. Only the R9150/R8050 TT/tri shifters are compatible, and the SW-R9150 satellite shifter.

          All other 11-speed shifters / switches will not work, unfortunately.

  38. Hi Carlton.

    I have two bikes setup with 6770 10 Speed. I have lots of spares, RD’s, FD’s, junctions, shifter etc. I have only ever used the external battery.

    One of my bikes, the RD and FD will not respond. Tried swapping out the FD, RD, junction box and Shifters.

    It is possible I swapped batteries between the two bikes at some stage. Have also tried dffferent battery holders and different batteries.

    The junction box shows a charge and a change signal coming from the shifters.

    Where is the firmware for the system? Is it in the battery or the battery holder?

    Thanks for continuing this great site – esp for people like me who like to keep old gear working!


    1. 5 minutes after posting this I realised what I had done wrong – all of the cabling is internal, and I use and external junction box mounted under the bottom bracket. I had removed the wires from the junction box to replace a rubber grommet in the down tube where the wires poke through. When replacing them, I had placed both ends of the battery wire in to the junction box and connected the battery directly to the SM-EW67-A-E Ultegra 3-Cable Junction. So obviously nothing was happening!

      1. As it turns out I also had a faulty battery holder (SM-BMR1) – swapped out for a different one and it all works fine.

        Do these go ‘bad’ for a reason? Are they sometimes incompatible with individual batteries? Do they hold any ‘firmware’. or is that all in the battery itself?

        1. Author

          I hear of these external battery mounts failing fairly frequently. I’m not sure why, but there is some design deficiency.

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