1. I have my fav c34 wheels which are 10 speed, I just got hold of a RD-6770 shifter (10 speed).. I assume I can operate that shiter with my Dura ace 11 speed levers? (ST-7970)

    Or will I run into some firmware issues (I tried to read a bit in the other comment fields, but unfortunately got lost)

    Thanks for a great article here

    1. Author

      Nothing from the first generation (4-conductor / 5-conductor) Dura-Ace Di2 7970 system is compatible with any other newer system. It was replaced by the (2-conductor) E-tube systems. No parts are inter-operable between 7970 and any other Di2 System. The wires are completely different.

      1. My mistake here! I’m mixing up two of my projects.. im trying again!

        Will 11speed levers (ST-9070!) fit an 10speed RD 6770 – they do both run on e-tube.. but not sure if it will work..

        In short i have a fully working 11 speed di2 setup, and I want to replace my 11 speed rear dereailuer with the 10 speed RD-6770, due to my wheels…

        Will that work?

        1. Author

          The levers will work with the 10-speed rear derailleur. However, a 10-speed rear derailleur will not work with a 9070 (11-speed compatible) front derailleur. The front and rear derailleurs must both be 11-speed or must both be 10-speed compatible. This limitation is built into the Shimano firmware.

          1. Great thanks for your answer, do you know if they will work automatically or do I need to program something in the e-tupe app/software?

          2. Author

            It should work automatically. If it does not, you will need to update firmware via the Shimano eTube app (Windows + USB adapter or Mobile + Bluetooth component.)

    2. Some (many?) 10 speed wheels can have 11 sprockets put on them and that might be the easiest solution. In some cases using the wheel as the lathe and a dremel to grind the freehub body works. This does not work well with actual Shimano freehub bodies because the spline slots are not well-formed inside of the original mounting face. In some cases new freehub bodies are available and a bit of redishing the wheel works; this is true for some Shimano 10 speed wheels. In some cases machining the inside of the inner rear sprocket cluster works, noting that the same money to buy a 10 speed electronic system could purchase a harbor freight mini-lathe to do such work. And there are probably still a few commercially available 11 speed casssettes that fit 10 speed rear wheels, for example I believe the Shimano 11-34 mountain 11 speed cassette, and I believe Recon still makes one that may be in a hidden menu somewhere. In the case of Mavic no extra work is needed. And in some cases there is not enough room and there is no easy way to make the room.

      1. Thanks for good comments here, I agree there are some solutions which can make it work-ish… dremel through those beautiful DA hubs is not an option. I have had succes of simply remove a sprocet from the 11speed cassette and space my way out of it…

  2. Hi,

    What a wonderful resource this is. Thank you.

    I have a simple question you may be able to help me with.

    I have an Pinarello F12 which I wired myself using the 9150 wiring and the in-frame charging point on the down tube in the normal way.

    I want to change the frame to the new F (F14) which does not have the in-frame charging point and is designed for the new 9250 wiring with the charging point located on the rear derailleur.

    I remember the 9150 coming with connectors that allowed the installation of the charging point to be located at the bar ends, which I still have and might offer me an alternative if I move to the F (F14).

    As I don’t really want to go to the expense of buying the new 9250 rear derailleur, would it be possible to convert my existing 9150 in-frame wiring set up to the bar end type?

    I can’t remember exactly what length cables I used nor what all the connections looked like.

    Presumably there were two connectors from each of the shifters that ran through the integrated handlebar and stem and then connected to a junction box which I positioned below the stem in or near the head tube.

    This was then connnected to the in-frame charging point half way down the down tube. I also think that I connected the EW-WU111 somewhere around there, as well.

    This was then in turn connected to the front derailleur, rear derailleur and seat-tube battery via one cable.

    Any help or simply a positive acknowledgement of the feasibility of what I’m trying to do and what extra parts (cables) I might need (if any) would be gratefully received.

    1. Author

      Hi Carlos, you can definitely switch to the bar-end charging port. Worst case, if you don’t have an extra unused port, you can add extra ports. To do this, you will use the 4-port SM-JC41 Internal Junction. You will also need 2 additional e-tube wires (one from the front junction to the SM-JC41, and the other from the SM-JC41 to the bar-end charger. And if you do already have an open port, you only need one e-tube wire and the bar-end charger. Good luck with your bike swap!

      1. Thanks for that information. I won’t be sure how many free ports I have until I strip the bike but even if I have to buy one cable, it doesn’t seem too much of a task.

        I’ll let you know, for other people’s benefit how I get on.

        Best wishes,

  3. Reverse engineering the Di2 protocol isn’t as hard as that last entry makes out.

    The whole E-tube bus is in parallel – you just need to cut a spare wire and stick it in a spare port to read all the signals with a scope.

    1. Have you tried that? I did not understand what I was seeing on the scope, and did not pursue the project further.

  4. I have an entire Ultegra di2 6770 group/kit, do I need to buy only the Ultegra di2 6780 11v rear and front derailleur, to transform my kit into 11v? would that be it?

    1. Author

      Correct, that’s all you need. Plus maybe a firmware update. And a new chain and rear sprocket.

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