1. PC only, sadly. When you see how easy it is to port from Object Orientated Programming it is surprising that both platforms are not addressed.
      However, I run a PC hard drive on my Mac Pro and it is used exclusively for Di2 diagnostics. This enables me to have the best of both worlds and run a dedicated drive which I can trust has no software issues when configuring Di2 systems.

      It’s a wonderful world.

      1. hmmm… ok then 🙂 just installed the DI2 and the SWr671 does.nt seem to work? think it’s software yes?
        everything else is working.
        Just LOOOOOOOOVE this website

        1. If you are running all 11-speed or all 10-speed FD/RDs then as long as the firmware on each component is updated you should be good to go.
          If you use the Shimano E-Tube software and the diagnostic unit you will be able to isolate any issues.
          It is important to follow carefully the Shimano procedures on diagnosing issues. Do NOT plug/unplug cables while running the E-Tube diagnostics. Patience will pay dividends.

          1. That’s why i need the software need microsoft for free somewhere if i need to update something running Mac no updates at all

  1. 7970 Di2 RD Issue

    Hi All, Great thread and a lot of great information!

    I have recently purchased a complete 7970 Di2 kit which when I collected it all appeared to be working fine and the seller seemed genuine and showed me it working.

    I have now transplanted the kit onto my bike and have an issue with the rear derailleur ghost shifting. What is happening is as follows:

    If I am on the largest gear, no.10, and drop down a gear to 9, it drops fine. If I do nothing for 5 seconds, it will then drop to gear 5 or 6 on its own without me doing anything. I then get two flashing red lights on the junction box as if showing a fault. If I try and shift down again, it will shift down, but reaches gear 1 and then because it is out of sync in the gears, it tries to keep shifting down but can’t because of the limiter.

    If I shift back up, it will get to 7 going gear by gear and then stop. I have to wait about 10 seconds before I can try and get to gears 8,9,10. It gets there in the end, but it can take up to 15 seconds of delay in trying to upshift.

    What is strange is that if I am in gear 10, drop to 9, wait 2 seconds, and then drop one by one every 2 seconds or so, it will shift up and down fine. It is only when I drop into 9 or 8 and want to leave in those gears that it ghost shifts.

    I have taken the rear wheel out and removed the chain, and it still does this, so I believe it can’t be a chain or alignment issue as there is nothing to resist it.

    I have tried to find info online, but it is virtually non existent when looking for two flashing red lights as an indicator.

    The kit came with an internal wiring kit, and I have purchased an external wiring kit new for it, and it does the same with both wiring harnesses, so I don’t believe this is the cause.

    Any help and advice would be extremely grateful as I am a bit stumped and don’t want to fork out for a new RD unnecessarily!



    1. You don’t mention whether you firmware has been checked and is up to date using the PCE-1 diagnostic tool?
      Have you tried using another [borrowed] RD to isolate the RD from the equation? Your local bike shop or a mate might oblige with that.

      1. not applicable, this is not an e tube system, its 7970.

        1. Correct, as it is 7970 I cannot update firmware.

          I have ordered online the Diagnostic checker for this Di2 model, but have to wait a few days for it to arrive.

          I am just after any advice and info that might help as well!

          1. from my experience that diagnostic box is worthless, as it cant seem to detect a RD about to fail, only after it fails completely can it detect a fault, see my previous post.

        2. Indeed. I read 68 rather than 79.

    2. OK… from you discretion this is what happens when the RD is about to fail completely. to verify that this is the case check for 3 things. 1, see if you can get it to do the fine adjustment bu pressing on the junction box button for ~4 seconds, it should show the red light solid, and allow you to adjust the RD position by the right lever buttons, if its not adjusting or flashes red when you try this its the RD about to fail. 2, Also if the RD will not reset in crash mode, i.e. remove the rear wheel, hold down the junction box button until the RD starts to reset… moves through the full range and stops at the highest cog position than, if it will not do this than its also an indicator that its the RD about to fail. 3, if the bike was ridden in the rain, or was washed, and needs to dry out, in this case it should be ok, but could still be about to fail if enough moisture has gotten into the RD.

      1. Hi. Really appreciate the feedback!

        I can get into the fine adjustment, but it only moves about 3 moves each way, not the 20 or so I am led to believe it can do.

        If I press and hold the junction box button, it does go through the range and stops at the highest cog, or maybe position 8 if not.

        If it is failing or about to fully fail, are they repairable, or are they completely useless and not worth looking at?

        Many thanks again!


        1. when the RD fails its toast. the fine adjust only going 3 steps is not a good sign, also if the red light starts flashing two times this is also bad. the only other thing to check is the front harness, and the diagnosis tool MAY be able to detect that, or not. so far it’s looking like the RD is the problem!.

          1. Thanks again for the feedback!!

            I’ll wait for the diagnosis tool to arrive and see what it says.

            I don’t have a second front junction A box to test with, so it could be that.

            Here’s hoping it is the cheaper part of the two!!

            Thanks again

  2. Hi Carlton, Awesome bit of work, and helped greatly during my installation. However i have installed on my LOOK 675, but have found that drivetrain is not smooth – old mechanical was silent, di2 is not – its really getting on my nerves. I cannot work it out. Im running the GS cage on 11-25 cassette, followed all the guides, checked rear hanger and still noisy – any tips? cheers ash

    1. Hope my sleepy eyes have read you correctly.

      In my experience the GS does give comparatively more ‘feedback’ compared to the SS. However, it sounds [pun?] like your feedback is not normal as it is ‘getting on your nerves’.

      What series of Di2 are you running and a the components speed-consistent?

      The longer cage does leave less alignment room for obvious reasons.

      Don’t expect a Ferrari to sound like a Corvette. 😀

      1. Hi James, I’m running the 6870 group set all brand new. Not sure what you mean by speed consistent. What it sounds like is something is constantly rubbing,with the front mech but I know that this is not the case as the clearance is more than enough.

        1. I don’t know if this is your issue with regards to the rubbing, but check that the rear derailleur cogs are not meshing with your largest cogs on the rear. I had a similar issue and couldn’t work out the noise. Basically the B screw wasn’t long enough to extend the derailleur out enough on the larger cogs so the two gears were meshing through the chain.

          The noise going down the chain made it sound like the front derailleur was rubbing when it wasn’t.

        2. Thanks. I was asking about your Di2 just to get the total picture. Problem-solving is always helped by full information.

          Make sure the head jockey wheel is clearing the cassette properly when in the large ring of the cassette. If you don’t have sufficient clearance that would generate feedback [noise].

        3. Hi
          I was referring to the older practice of mixing 10 with 11 speed components. This can give drivetrain feedback.
          As your drivetrain is all new, wear and tear is excluded. I assume the new components are speed-consistent.
          That leaves us with two options; the issue can only be a faulty component or a bad setup.
          More than likely it is the latter.
          Be sure to carefully read the manuals and setup advice. It isn’t too difficult.

          1. so i have had the whole setup ‘reset’ by a qualified tech, seemed to work fine for a couple of days then got an annoying clicking again as if it was trying to overshift. adjusted. Went to a ride friday, and shimano were there so asked the tech to have a look – he said it was very slightly out. Rode it and it seemed fine, day after did another ride and started to get the same sounds. Now today, when i the smallest sprocket the chain is rubbing in the front mech, also noticed that it was making a horrible noise in the 5th sprocket from the bottom. Reaaly starting to get me down, i know i will get a mechanical noise riding in the extremes, but this is too much.

          2. I have setup dozens of Di2 drivetrains on a lot of different frames and found that the chain line is what determines how the bike rides small to small. Sometimes you just can’t ride small to small, if you get rid of the noise by just riding up one cog than that’s what you do. I have 3 bikes now, two I can not ride in the 39×11, one no problem it’s just the differance in chan line. Also chain tension can make a difference if it’s on the loose side big to small… this is a commen problem with a bike with a 53×11-28 since having it too tight on the 53×11 will not allow you to get to the 53×28. Since these are both extremes that should not be used just say no, and shift before you get crossed over. Also some crank sets do have more runout than others and this can limit how well you can setup the bike.

  3. Hi There, Great post.

    For the non-tech of us…
    I have a 2011 Di2 Dura Ace equipped bikes. i’ts a standard bike, non TT.
    It has the regular ST-9070 Dura-Ace Road Dual Control Brake Levers/Shifters combination.

    I would like to add an Aero bars equipped with Triathlon bar end shifter. Here it’s listed as SW-R671 Dura-Ace 2-Button, but i found them on Ebay listed as Di2 Dura-Ace 7900 ST-7971 (http://www.ebay.com/itm/Shimano-Di2-Dura-Ace-7900-ST-7971-TT-Triathlon-bar-end-shifter-pair-/262008082098?hash=item3d00e60eb2).

    I was told by my local bike shop that it’s not possible.

    I’m guessing that you would have a better answer, seeing the level of expertise you have here.

    Can you Tell me which parts i will need to accomplish this task?

    Thanks a lot.


    1. Author

      Arik, your question is answered in the original post above:
      “Because the first generation 7970 used completely different technologies than the newer 2-wire systems, none of the components are cross-compatible.”

    2. You need to make sure what system is on your bike. The Dura-Ace 9070 11 speed was not released until 2012. Prior to that, the Di2 Dura-Ace system was the 7970 10-speed system. The two systems are not compatible.

      1. I have an early version 2011, the 10 speed system Dura-Ace.
        I understand that the two are not compatible. Question is, are there compatible parts (TT Bar end shifter) to go with my 2011 9070 10 speed system.

        1. The confusion is because you are calling them 9070, but it sounds like you actually have the Dura Ace 10 speed shifters, if that’s the case than the ebay item will work. You will need exetention cables that can also be found on ebay.

          1. You are right, and maybe this is the source for confusion. i do have the 10 speed system STI shifter+breaks, Dura-Ace. its a regular road system. not a TT. So its really is a Di2 7970 STI 10 Speed. So going back to the original question. Will the ST-7971 bar end shifter do the trick for me? What other parts will i need? I guess i need a 5-ports junction box? which type?

      1. This is getting better. What you are saying is that i need the ST-7971 and the extension cables only?
        So the ST-7971 are connected directly to the STI Levers which are already mounted in my Bike? No need for a 3/5 ports junction?

        1. Yes that is correct. Besides the 3-5 port you are asking about will not work with your 7970 system. You will need to use a plug tool to plug the extension cables in.

          1. Great Answer and support. Thanks a lot. I feel quite confident now to buy these items. Have a feeling it’s going to be an easy one. Btw, do you have a recommendation for an Aero Bars that fit the TT Shifters?

          2. No.

  4. What is the trick to remove di2 shifters out of the TT bars. they went in ok but getting them out – mmmm . . . not too easy ?

  5. I make it from your answer Carlton, that TT Bar end shifter comes only as 2nd generation? i.e. 2-wire system?
    There are no components compatible with 1st generation?
    From the link i’ve provided (from Ebay), it does looks like this is a first generation. inst it?

    1. If they are first generation 79xx series they are not compatible with your second generation system. If they are second generation 97xx/67xx/68xx, they are compatible with your second generation system.

  6. Anything that allows you to insert a shifter into the end will work. The actual shape of the bars are an individual thing and mainly depends on how much you want to bend your wrists.

  7. Anyone able to tell me how to get the Bar End Shifters (digital) out of the aero bars ? Im afraid to “force” something is likely to break ?

    1. Instructions for all Di2 stuff can be found at the Shimano web site. I believe there is a link from this page.

      1. The manual that is linked on this page explains it very well. I just looked it up.

  8. Hi Carlton

    Sorry if this has been covered. If I want to change from the external battery to the interval do I only need

    The pipe style battery
    The 5 port connector to replace the one I have.
    The charger

    Also do you know if the battery will fit in the aero seat tube of cervelo S2. The reason to do this is too allow me to use 2 bottle cages again

    Also on my black and white p3 is it safe to drill the top tube to convert to di2. I think you have covered this but I’m nervous about drilling as there must be a cable guide in the top tube for the brake cable. I think I will also need to use an internal battery because of the frame shape

    Sorry to bother you with all this but you know your stuff.



    Sent from my iPhone

    1. Author

      Hi Ian. Yes, those are the only components you need.

      I’m not positive that the battery will fit in the seat post, but if not, it will almost definitely fit in the seat post down tube in the frame. For my Cervelo P2, I originally squeezed it in the seat post, but didn’t like that I had to disconnect the battery every time I remove the seat (for travel purposes.) I much prefer having the battery down in the frame, with some extra tape around the wire and battery to make sure it doesn’t disconnect.

      Don’t be nervous about drilling your carbon fiber frame. It’s no big deal. Just stay away from the points where the tubes come together. So on the top tube, at least an inch away from the head tube. Start with the smallest drill bit you have, and work up one drill bit size at a time, until the hole is large enough to pass the wire through and then install the grommet.

      1. Thanks Carlton. Much appreciated. Ian

  9. Hi I am busy setting up dura ace 9770 di2 on my bike so i thought i would connect it all together and check to see if everything is functioning before installing it. I am using an external battery as it is going in a cervelo P5. I charged the battery first then connected the system up but it appears completely dead and there is no response from the Junction A. I have checked all the cable terminations and they are all well plugged in. Have i missed something obvious?

    1. What does a battery check show?

  10. Hi .I have just purchased Ultegra6870 di2 with external btr1 battery and mount.when connecting everything up there is no lights on junction a (3 port type) just nothing ??? there is power from the cables as it lights up a bulb at every point but when you plug in the A junction there is nothing wondering if it needs a diagnostic please can you help on this

    1. All sorted.. just needed a firmware update. Glen I am pretty sure that is all that is wrong with yours

  11. I have been riding a Jamis with Di2 shifters for a year with no problems, Recently, when I tried to shift from the small to the large gear in the front the shifter threw the chain off the gears to the right. I took it in and guy guy said that was because I was not pedaling while shifting . Is that the cause ?
    He “adjusted” it and now it still throws the chain off to the right at times but also
    will not shift from the big front gear to the smaller one unless I am in the third
    biggest gear in the back. This results in my being in a too easy gear ratio so I have to immediately shift the back gear to a smaller gear in order to apply force to the bike. What is going on?

    1. Get a new mechanic guy guy has not set it up correctly. There is a link on this site to shimano and instruction for setting up the FD & RD are easy to follow.

    2. Di2diy is correct.

      Assuming your components are not damaged/worn your Front Derailleur should NEVER drop the chain off the right of the chainset. Dump the junk mechanic. And what a pain slicing your great kit with a mis-installed FD! Slap him HARD [metaphorically speaking].

      Adjusting the Di2 is something you should be able to do on your own. Download the Shimano manual and follow carefully the instructions. This done, your drivetrain will run beautifully.

  12. di2diy – it wont let me reply to your reply. What do you mean by run out?

    1. Like the trueness of a wheel, side to side movement. The issue with the 5th position noises is fine adjustment it needs to be adjusted. There are link to instructions on this site, go over them and read it all step by step, it’s not that hard. Di2diy at gmail dot com

    2. Like the trueness of a wheel, side to side movement. The issue with the 5th position noises is fine adjustment it needs to be adjusted. There are link to instructions on this site, go over them and read it all step by step, it’s not that hard. Di2diy at gmail dot com

  13. Hi, Curious about where in the system the firmware is actually stored. Is it in the battery? Can I just get the part and not update it to go back to an older firmware for the whole system?
    Whats the easiest way to find out what firmware my system is on?

    1. The firmware is stored in each componts FPGA and is unique to each component. The only way to see what version in installed on each component is to plug it in to the e tube updater PCE1 or BCR2 connected to a PC. Firmware can not be over written with older versions and all components must have the latest version for that component to function properly in the system.

  14. hello,
    I leave a question here because I can’t find information, or when I found it can’t verify it.
    I bought a BMC SLR02 with Ultegra Di2 6870, with 52-36 rings and 11-28 cassette.
    I plan to ride in the Alpes like Alpe d’Huez, and I would like a bit more comfort with a Miche light cassette 12-30.

    My rear derailler is a 6870 SS – short cage – and I could find in one site that it’s compatible up to 30 tooth.
    But I can find this info only one one site, not others. Other sites don’t say any thing or they say the limit is 28 because of course the standard Shimano cassette is 11-28 …

    but as Miche provide other cassettes will this work with a 12-30 ?

    I understand I would need a GS – mid cage – with a 11-32 … but does the 30 works with a Short Cage ?

    I don’t want to change my rear derailler.

    thanks for your opinion or any info on that topic.


    1. Stephane,
      Miche’s cassettes do not determine what your Shimano RD can cope with. There is good reason Shimano advise you will need a 6870-GS if you want to run rings larger than 28t. If you are riding away from base it is wise to run a secure system in order to avoid issues.

      There will always be users who love to ‘fiddle’ with their setup.
      Shimano short cages are NOT designed to run with cassettes larger than 28t. If you want a larger ring on the back, say an 11-32t cassette, you are well advised to use the 6870-GS to avoid mechanical issues. See here:http://productinfo.shimano.com/#/spec/2.3/ROAD%20Di2%20spec/Rear%20Derailleur?q=RD-6870&popup=

      Froome is on record as running large rings even when he does’t need them, ‘just in case’ you find yourself looking for a larger ring on the back. Check out YouTube and the Giro where you will see numbers of Pro’s running the Ultegra GS so that they can run 30+t on the cassette.

      If you do swap out your SS for the GS you will need to adjust your chain length accordingly.

      Enjoy the climbs with their descents and stay safe.

  15. Problem: 7970 will not go into adjustment mode. Took to local shop/shops and told can’t be fixed. Would a new front wire kit SM-EW79A hold the solution?

    1. This is what happens when you’re RD is about fail… soon, if it has already started skipping shifts it will soon and will fail ultimately of course you can always try to replace the front harness I doubt that that’ll fix it.

      1. As with most things, I don’t give up easily. So, I contacted Shimano, spoke with a tech, did some troubleshooting and boiled it down to a problem w/front harness – SM EW 79A. Bought one and installed this afternoon. We’ve got a fully functioning Di2 system.

        1. Well than that’s a good thing, and although I was doubtful sounds like it was worth a try, and an easy fix that hopefully it’s really the fix you needed.

  16. I used your help to convert my 6770 to an internal battery and its been working great until two weeks ago when the rear derailleur started acting sluggish. I thought it might have been the battery since the indicator on the junction box was blinking red. I recharged the battery when I got home and it worked great on the bike stand. The next ride after about 10 shifts the rd stopped working. E-tube recognizes all the components and all have the latest firmware. I tried your recommendations on rd testing and the micro adjust only work some times, the recovery mode does not work at all. The bike doesnt have a lot of miles on it. I assume from what I have read the RD is toast. My question is do the 6770 fail this often? I am hesitant to buy one off ebay if the next one is going to fail as well. Am I better to spend $$$$ more money to upgrade to the 6870 for more reliability? Lastly, I like to ride the big chain ring and with the local roller I do cross chain 50×28, Would this have any effect on the premature death of the RD?
    Thanks, Tom

    1. I assume you’re talking to me I have no idea what causes The RD’s to fail normally they’re pretty reliable but when it’s time it’s time I’m curious about your comment about the cross chain could actually maybe do something however I really think it’s an electronic issue with the servo some just last longer some just don’t last long at all I would recommend you do go to the 11 speed just because I think if the shift better I do find them to be more reliable. Glad the battery kit is still going strong.

  17. Hi Carlton,
    I’ve purchased a 2014 BH Aerolight with Dura-Ace Di2. It currently only has a pair of SW-R671 and a 5-port junction. I assumed I could get a pair of ST-9071, plug straight into the junction and away I go. Alas, no shift from the new ones. I am correct in thinking I’ll now need to get hold of an SM-PCE1 and hook this up to a PC to update the firmware to include the ST-9071 shifter addition? Thanks for the article.

  18. Hi, I ride a Merckx EMX1 with ultegra setup. RD6870 FD6870 6770 shifters sm40 junction external and sm ew90 5 port junction. and SM BTR2 external batterymount and external battery. The last few weeks I have had trouble wiht shifting. One moment all works well the next moment it does not shift at all. Today I tried to do a test with the pc interface. Nothing is recognized. When I charge my battery it is full off charge withing half an hour, so I asume it is not empty. When I replace the battery the problem is not solved. I changed the batteryholder and sm ew90 bit that does not help. It has a D-fly wireless unit. What could’t be the problem?

    1. Author

      Jos, you could have a shorted wire. I recommend disconnecting the wires from the junctions, one at a time, and see if removing one of them fixes the problem. You need to isolate the one wire or component that’s causing the problem, and eliminating them one by one and then reconnecting the PC interface, is the best way to do that.

      1. Hi Carlton
        I tested all the components one by one and there where no problems. The E-tube software told me I could have a defect battery. I tried antohter battery and now all is working well for the last two days. If the problem returns I am thinking about changing my external battery for a internal battery.

      2. hi Carlton
        Last sunday I took my bike and went for a ride. after 35 km the system stopped working. I installed the battery in my other bike and all worked well on that bike. I recharged the battery and installed it back in my merckx emx1 but nothing works. I replaced the wire between the front junction and and the the bottom junction but nothing works. WhenI test the components on the pc all is ok. I don’t know what to do next.

        1. Check all the plugs starting at the levers, unplug them and than plug them back in using the plug tool, be shire you hear the snap when you plug them back in.

  19. Morning Carlton,

    I have an 11 speed Di2 9070SS rear derailleur using the R600 shifters on a racing recumbent bike. I’m having a problem with the rear derailleur moving the chain from the first to the second second cog after a few seconds. This basically eliminates second gear, not good for climbing. I have the bike on a trainer for resistance and have followed your set-up instructions, but the problem still exists. I hope you have a moment for me, as I have an event tomorrow.

    Many thanks,

    1. Author

      Bill, my recommendation is to read through the Shimano installation/adjustment instructions, linked in the post above. Make sure you don’t have an issue with the limit screws or adjustment position/procedures.

      Aside from that, go into adjustment mode, and move the rear derailleur outwards by 1 or 2 button clicks. Exis adjustment mode, and see how it shifts. It sounds like the rear derailleur is very close to being in the correct position, and just may need to mover outwards ever so slightly.

      1. Thanks, got it to stay in first cog. I’ve been tweaking the low limit, but it still occasionally contacts the disc wheel.

  20. Hi!

    Great overview of Di2 issues and opportunities.

    I have a Tri bike with the following set-up:
    – ST 6871 Ultegra Tri brakes/shifters
    – SW R671 Ultegra Tri Bar end shifters
    – SM EW90B 5 port control box/junction
    – SM BTR 1 External Battery (might be ver. 2)
    – RD + FD 6770

    This gives a very bulky front end that I would like to clean up (difficult to “hide” teh 5-port box from the wind).
    In addition, I would like to “upgrade” to 11-speed.

    My idea is to exchange the 5-port-junction with an old SM EW67AE 3 cable control and 2 x SM JC41 Junctions (these will be inside the base bar or extensions).

    Will the “old” SM-EW67-A-E Ultegra 3-Cable Junction work in this set-up?

    Will I be able to exchange my RD + FD to the 6870 11-speed versions with such a set-up (SM-EW67-A-E + External battery)?

    Can I do this without buying the SM-PCE1 PC link?

    1. And if this works out, I am happy to do a trade with you. I have an EW67 that I want to upgrade to the 5 port.

    2. Yes that setup will work, and you will likely need to update the firmware. You may be able to find a LBS to do the update and not buy the PCE1. If you have soldering skills you can splice the front wires together and have just one wire coming from the front, you can use the EW90 and place it anywhere in the system, there only needs to be one wire going to the EW90, or EW67, as the system just needs to see the junction for the system to work. If you do use the EW67 and want to go with a seatpost battery I sell a custom system including inline charger that will work the the EW67, or EW90.

  21. So 11 speed rear derailleur will not work with a 10 speed cassette? This means that I would have to replace my Zipp Sub 9 if I want to upgrade to the new Di2 group set. Will the Di2 11 speed rear derailleur work with the Campy 11 speed Cassette? It sure would be a lot cheaper to change the rear hub to a Campy than to buy a new Disc.

    1. If you have a campy free hub body that will fit on your Zipp, a 11 speed campy cassette may work with your 11 speed Di2. I never tried it, but have read some riders have done that set up without issue. I think Velonews did a little report on it as well.
      There is this 11 speed cassette that will fit on a 10 speed ( http://www.trisports.com/edco-monoblock-11-speed-cassette.html ). Haven’t tried it but thinking about it.

      1. A friend is running Campy free hub and cassette with 9070 groupset. Campy cassettes and chains are generally more expensive than their Shimano equivalents though.

    2. Author

      I’ve heard the same, that Campy and Shimano/SRAM 11-speed rear gear spacing is almost identical. Not exactly the same, but close enough that you can get it to work.


      “the spacing between a Campy 11 and Shimano 11 is close enough that you can use the cassettes interchangeably. If you get a Campy free hub body, the 2 shims (part# is on the Zipp website, just search for campagnolo 11) and a Campy cassette and you’re ready to ride with all 11 cogs available to use.”

      1. I have read of a 11sp Shimano cassette reduced by one cog to 10 being used on older Zipps with 11 speed D12 Dura-Ace, presumably, with the range of movement reduced.

        1. To do that you need to set the stop screw so the RD won’t go to the cog that’s not there, and after a few of months the survo will fail from trying to shift, so do it if you can afford to buy a couple of RD a year. If you want to run 11 on a 10 speed wheel there are much better options, change the carrier and use a campy 11 or buy a Edco mono lock cassette.

  22. I’ve managed to accidentally cut through a Di2 cable for my Dura Ace TT rear mech shifter – stupid mistake, my fault entirely. Can I get the cable repaired/replaced without having to buy a new shifter entirely?

    1. Author

      yes, you can replace just the cable. It will cost about $30 USD. The problem is that you’ll need to get one of identical length. So you’ll need to disassemble your bike to get to the Junction B near the bottom bracket, remove the cut cable, measure it, and order a replacement of the same length. If you don’t have one, be sure to also get the cable remove/install tool and make sure you snap the replacement cable fully into place on each end.

      1. Forgive me if I’ve misread this Carlton but I think Numpty meant that he has cut through the shifter cable around the handlebar area in which case he obviously only needs to replace the cable from the shifter to Junction A?

        1. Author

          After re-reading the comment, I think you’re right Jeff.

          The only way to recover from cutting a cable attached to a shifter is to get out the soldering iron and splice it back together, and then seal it up really well.There are only 2 wires to join back together (after stripping off some of the insulation.)

    2. Cut, solder and seal [carefully]. Use some high quality silicone sealant and you will be good to go. You can also cover the sealed joint with a low-temperature heat-shrinkable sleeve [available from your electrical wholesale].

      Alternatively, replace the shifter.

  23. Hi Carlton. Great site and this article helped me change from 10-speed to 11-speed without having to buy. A new front derailleur. I just took my bike in to replace the front chain ring ring which was worn after over 15000kms of use and without me asking, bike shop plugged my di2 into their computer and upgraded the firmware rendering my 10-speed front derailleur useless with the rest of the di2 set up. They didn’t tell me that they had done this. They told me that 10 speed derailleurs dont work in an an 11-speed set up. They installed an 11-speed RD and charged me $360 Australian dollars. I subsequently worked out what had happened and confronted them about it. They admitted that he they’d accidentally updated the firmware to an incompatible version but refuse to cover the cost of fixing their mistake.
    Can you tell me if the update in indented your article with the warning about updating is from an official Shimano release? This one :
    Important Notice 2014-07-14: There is a compatibility issue with Shimano e-Tube software version v2.6.0 that prevents 10-speed front derailleurs (FD-6770) from working with 11-speed rear derailleurs (RD-6870) and 11-speed front derailleurs (FD-6870) from working with 10-speed rear derailleurs (RD-6770). DO NOT UPDATE FIRMWARE using Shimano e-Tube software v2.6.0 if you are running an FD-6770 front derailleur and a RD-6870 11-speed rear derailleur, or a FD-6870 with a RD-6770.

    1. I was the first to identify this issue some time back to this forum, and as a contributor to this very helpful site made Carlton aware, and he posted this warning. Shimano officially identified the non compatibility at the time of releasing the newer version, as well as in the previous version, but not until the new firmware release was there a effort to make them functionally incompatibly. Shimano warned users some time ago about the incompatibility, so you cant blame them, however you can blame the shop for doing something you did not ask them to do, but if they say tough luck, than there is not much you can do except take your business elsewhere. that is the reason I have always advised people on this site not to try and mix 10 & 11 speed FD/RD because it will eventually come to grief… I wonder if I look back would you be one of those people who were forewarned? 🙂 BTW a Ultegra FD from RIBBLE is AU$226.33, so you may want to ask why they charged you 360. unless its a Dura Ace.

      1. How sad that the LBS ‘admitted’ to causing the problem by upgrading the firmware without your asking them to do so! You have a legal remedy, if you think it is worth pursuing. Or, you could strong-arm the LBS by warning them that you will alert the users in Social Media. Name and Shame can work. If the LBS does not see the value of the customer then the LBS will never flourish. Name ’em and Shame ’em, I say.

        Kudos to Di2diy for flagging up Carlton and Kudos to Carlton for post it here.

        Shared knowledge helps us all.

  24. hi could you inform me if the bcr2 charger can configure the di2 via e-tubeproject.shimano.com is it official .As I’ve done firmware updat to my ultegra di2 6780 which is a 2015 model and the front deraileurs is not recognised in the software and my lbs doesn’t I can and won’t be a warranty claim .

    1. No such thing as a 2015 6780 Di2. Do you have 10 speed 6770, or 11 speed 6870? Are both FD and RD 10 speed or 11 or are the mixed. Have you ever done an update before now?

  25. Is the bcr2 di2 charger officially able to do firmware updates by shimano Co I might have a warranty issue

  26. Whats the difference between the BMR1 and the BMR2 battery mounts?
    Does it make any difference which one I get?

    1. BMR1 is the first mount released with the 6770 ultegra 10 speed. BMR2 mounts were released with the 9070/6870 components. If the BMR1 is updates with the latest firmware it will be the same as the BMR2, and will work with any series of e tube stuff. BTW it will most likely be necessary to update a BMR2 as well before it will work with any of the current versions of e tube components.

    2. Keep in mind if you are running the SM-EW90 with the BRM1 or BRM2 you may need to update your firmware to remove incompatibilities. If this is so, update them independently using the the Shimano ETube software.’

    3. denwol; NOTE 2: The SM-PCE1 PC Interface is needed to upgrade the firmware on the external battery/mount. That may be a factor on whether you opt for the internal battery set up or the external.

      1. That is incorrect. You can update the the BMR1 with a BCR2 and a EW90, or a PCE1.

    4. NOTE on NOTE 2: One cannot update the firmware on the BMR1/2 using a USB>PC>E-Tube Software via the SM-EW-67-AE as the port on the EW90 is not available on the earlier 3-cable junction.

      Di2diy is correct, ‘ You can update the the BMR1 with a BCR2 and a EW90, or a PCE1 ‘.

      Sharing with a smile is the way to go, guys; its the way to go.

      1. Thanks,
        So you can use the BCR2 with a BMR2 and BTR1 as long as you have the EW90?
        I can then charge through the charger port rather than take the battery out of the mount each time to charge?

        1. You cannot charge through the EW90, but you will be able to update the firmware.

  27. Hi,

    Any luck running a Ultegra 10 speed rear mech, and Dura Ace 10 speed front mech with Ultegra shifters? I only ask because I am currently running 1x ultegra, looking to go back to 2x and eBay has Dura Ace front derailleurs cheap for some odd reason.


    1. They are in no way compatable.

  28. Is it possible to mount the long cage of a mechanical ultegra or 105 rear derailler on a ultegra Di2 6870 rear derailler. I want to use a sprocket with 30 or 32 teeth

  29. Greetings:

    Learned a lot after accidentally landing on this site.
    I am a newbie w.r.t. Di2 and not well-versed with tech terms used here.

    1. Can I use an SC-M9050 Display Unit on my basic Di2 System which is 11-speed Shimano, three-port junction and internal battery. Bike is a 2015, manufactured late 2014; everything is dealer installed. Yes, all three ports are occupied.
    2. Is hardware update performed using the same USB cord that connects SM-BCR2 charger to junction box for battery charging?

    1. Yes you can replace whatever junction box you are now using with the SC-M9050.

      1. Then, based on your reply, I assume that SC-M9050 is both, a junction box as well as a digital display . Correct?

        1. Yes, and you can only have one junction A in the setup.

  30. Any reason a 6870 front mech would come up as incompatible in etube software (other than mech being fried). Running 6870 rear mech and happy with all other components in the system

    1. The only reason would be that it’s not the same version as the other components.

      1. Thanks for the reply. Are there different versions of the 6870 front mech?
        I’m running a 6870 rear but 6770 shifters which I know are compatible
        Everything works fine with two 6770 mechs and with a friends 6870 front mech
        I’ve picked up a 6870 front from eBay that comes up as incompatible

        1. You will need to update the firmware on the FD, it will work as long as both FD & RD are both 6870, but the FD firmware must match the RD.

          1. Many thanks again for the reply but with the FD coming up as incompatible, it does not allow me to update the firmware (the option to do so is ‘greyed out’ in the etube software) – am I doing something wrong?

          2. are you using the PCE1 or BCR2?

          3. I am using a BCR2

          4. With the PCE1 you can do one component at a time, with the BCR2 you need to go through the junction, so try disconnecting everything but the FD and see if you can get it to update.

          5. Seem to recollect Di2 6870 Dealer Manual DM-UL0001-00 suggesting that SM-PCE1 gives access to more advanced features over the BCR2 option.
            Enquired. Seller quoted $199 🙂

          6. Yes the PCE1 has diagnostic capabilities that the BCR2 does not have, and allows you to do direct updates on single components, but the BCR2 has the same update capabilities, only you need to have the junction inline since that’s where its plugged in. Just try and update the FD without all the other components plug in, and it may work, if not find a LBS that has a PCE1 and have them do a diagnostic to see if the FD FPGA is bad… possibly why some one sold it on ebay.

          7. needs adjustment. Also invest a few bucks in a chain catcher.

          8. Have disconnected everything but FD and am still getting the error message ‘A unit not supported by the current E-tube Project is connected’

          9. So find a LBS that has a PCE1 and do a diagonastis to see if the FD is defective, and if so tell the seller you bought it from that the item was not as described, and open a case to return the POS they sold.

          10. I assume you are connected to the Internet and e tube project is able to connect to the Internet to check and down load the current version, right?

          11. Hi, Yes, the e-Tube software is updated to the latest version and is on a computer connected to internet thanks. I have requested a return from the seller on eBay
            Thanks for all your help

          12. As a newbie, I was experimenting with my 6870 system: tried shifting to a tougher gear ratio by pressing both, FD as well as RD switches. Chain came off the front.

            Question: While I don’t see a reason to shift both derailleurs simultaneously, does the chain falling off in this case, indicate mal-adjustment of FD? Shifting is normal and quiet, otherwise.


  31. Anyone have difficulties slotting the wire into a R785 brake lever?

  32. Just got the ‘First Free Service’ on my new, Specialized Di2 equipped road bike.
    Somehow, I feel the shifting characteristics have changed after the service. Need informed opinion to clear up whether my problem is real or imaginary. Here goes:

    While the shift from large chainring to smaller chainring is immediate as before, there appears to be a lag in shifting from small to the larger chainring. That is to say – with chain on smallest rear gear it takes almost two revolutions (could be 2.5 revs) of the crank before the front shift actually takes place. I seem to recall, under same conditions, that front shift was instantaneous either way.


  33. Hi Carlton,

    You mentioned about splicing a Di2 wire to the SM-BCR2 charger so that it can charge the BCR-2 battery if the Junction A is not accessible. Is it possible to connect another Junction A to the RD wire and plug the SM-BCR2 to the external Junction A to charge the battery?

    Thanks in advance.

    1. Author

      I haven’t tried it, but for the purposes of charging the battery, that should work.

    2. Yes you can do that, but you can only have one junction in the system, so you would need to disconnect the other junction.

  34. Repeating my earlier (2015-December-01 at 7:21 am) question:
    Subject: Time lag in FD shift – from larger chainring to smaller and vice versa

    Just got the ‘First Free Service’ on my new, Specialized Di2 equipped road bike.
    Need informed opinion to clear up whether my problem is real or imaginary:

    While the shift from large chainring to smaller chainring is immediate as before, there appears to be a lag in shifting from small to the larger chainring. With chain on smallest rear gear it takes almost two revolutions (could be 2.5 revs) of the crank before the front shift actually takes place. I seem to recall that FD shifting was instantaneous either way, prior to the ‘First Service’.


    1. It should always be “instantaneous”.

      1. Servicing dealer corrected FD for chain falling out (as in out) – by tinkering with mechanical screws alone; not by re-programming .
        You think they over-compensated, causing this anomaly?
        If so, what exactly can I do to revert to instantaneous action. Time for DIY, I guess.
        Thanks, as always.

  35. Purchased DA-9070 with SM-BTR2 new 4 weeks ago. Connected all the wiring including home-made tactile switches in lieu of sprint shifters. Without chain fitted, I could see RD and FD shifting fine. Then stupidly I decided to update FW. I think there were 3 FW updates, but one failed, poss. SM-BTR2, so I disconnected all other units in situ as advised and SM-BTR2 updated. Don’t think I paid enough attention to what was detected, but at some point I lost the RD. I now have all units with latest FW, but no RD detected. No luck with RD-9070 + wire + Junc A + SM-BCR2 to PC (bearing in mind Junc A has no recent FW updates). Will SM-PCE1 help fix RD problem, or should I just send back to shop as faulty ? Could I have corrupted the FW ? Thanks.

    1. Hi
      I have ultegra (latest version) di2 3 port junction box. Thinking of getting some bar end shifters for clip on TT bars. Do I just need the 5 port box and wires straight from shifters into box? Anything else I need to do?
      Thanks. Henry

    2. Is the computer able to connect to the Internet to check for latest e tube project version?

    3. Update: Had to use SM-PCE1 to fix this, as advised by Shimano. Initially E-tube couldn’t detect the RD, then diagnosed and rolled back FW. Couldn’t fix with SM-BCR2 + Junc A + RD. Advice for novices like me: caution before updating FW, don’t plug/unplug any wires as advised in E-tube, safest after ‘Complete Setup’. RTFM in E-tube Help first !

  36. All available pics of eleven-speed NON-Di2 FD display a “skid” attached on inside wall of chain guide. There appears neither mention nor depiction of a skid on the Di2 set up.
    Question: is inner wall of chain guide of Ultegra Di2 FD supposed to be fitted with a plastic skid purported to avoid chain rub?


    1. I’ve had a 6770 and 6870 FD and neither one had anything affixed to the inside of the cage.

      1. Thanks, Robert. That addresses my concern completely. Basil

  37. I am getting a new FD-6870 and need to update the firmware on my bike. I have an external battery mount. Do I need to remove the battery to do the update? Does the battery mount need to be updated by itself? The spare ports I have are on the shifters and I have the SM-EW67 front junction.

    1. You will plug into an open port on the shift and begin updating everything. The battery will be the first check in the update sequence.

  38. I’ve got a 2012 Ultegra Di2 system, tried to use a Ultegra 6870 RD to upgrade to 11 SPD, it doesn’t work at all ? What do I need to do? I understood as it was pre 2014 system it would run mis- matched?

    1. Author

      Stuart: It won’t run mismatched if the RD has new firmware that isn’t recognized by the other components, which it does. You need a new 11-speed compatible front derailleur and updated firmware on everything.

      1. Thanks for prompt reply, what if I update to latest firmware and only use a 6780 RD? Presume this won’t work with with my 6770 FD . So my only option is to then buy a new FD 6780.
        From what I’d read it is possible to run mismatch if firmware is only updated to pre 2014 not the latest version, cannot this be done if using a RD that is designed with latest version of firmware which my new one obviously is.
        If I do end up with latest firmware and new FD and RD to get it to work would it be possible to reuse my 6770 10spd FR and RD on the bike at all?
        Thanks, can’t get my head round this. Stu.

        1. To run the 6870 on a mixed 6770 setup the RD and FD must match. The levers will work, but you can’t mix the detailers. There is no way to roll back the firmware. So your choice is put the 6770 RD back on and stay 10 speed, or buy a 6870 FD if you want to go 11 speed.

        2. Yes your old 6770 setup will work if you update the firmware on everything including the RD&FD, but that assumes to was working before you upgrade.

          1. Still confused, on other UK forums folk have successfully run a mis matched system by only having firmware updated to allow 6780 to run not the latest firmware, there is a link to previous updates on here, isn’t this possible ?..” The etube screen didn’t recognise the FD (6770) but apparently it worked once disconnected from PC.”
            Got a Shimano PC connector on route to me as we speak so soon be able find out. Can I just update to previous levels or will it automatically go for very latest?
            I’m just trying to save the expense of both RD and FD ( I’ve got both 6780 ones but can send FD back if can get 6770 FD to work.

          2. No such thing as 6780, I have been assuming it’s a typo, 6870 is what you are talking about. Your problem is the RD6870 has the latest firmware version and that’s why it won’t work, you can not roll back the version on the RD6870 so it won’t matter what version of of e tube project on the computer. The money you spent on a PCE1 should have gone to buy the RD6870, but having a PCE1 is helpful to have, but it can’t fix this issue.
            Just buy a FD6870.

          3. Yes it was a typo 6870!
            Well I can now report I’ve got it working! 6870 RD GS rest 6770 inc 6770 FD!
            What I did was download the firmware version off here for before Shimano stopped allowing mismatching, disconnected my PC from Internet , connected the loaned SM- PCE1 to the bike one into spare port on RH lever other into battery holder, following onscreen prompts it told me to disconnect the lead from RH lever, it then updated battery holder, re connected to lever it then went and updated all 6770 components, allowed me to customise shifting to multi shift mode , I then exited and removed cables. Swapped RD to the 6870 and hey presto 11 speed and FD 6770 still works, swapped out cassette (11-32) and replaced chain to 11 speed and adjusted it all.
            Out of curiosity I tried 6870 FD and that also functions.
            I now appear to have fully mismatched system so long as I don’t update firmware past where I am now.
            Thanks to you and Carlton for this site and all your input.

          4. Interesting without seeing the actual version of the BMR1, I would assume that it was something like a 1.1, and is updated to 2.01, and the RD6870 was actually not at the latest version as I assumed, so the reason it didn’t work before wasn’t because of the RD, but the battery mount. So looks like you lucked out, but just be sure that it doesn’t get updated beyond its current version. Good job and good luck.

  39. Great site, thanks Carlton and the other contributors. I want to reprogram the shifters on my brand new UDi2 as follows:
    – Right hand, any button: shift up the rear cassette
    – Left hand, any button: shift down the rear cassette
    – Simultaneous left & right: change front chainring (up or down). Basically,
    shift to the other chainring If on small, go to big. If on big, go to small.

    This last one is the tricky part, methinks. Thanks in advance.

    1. I, too, just acquired a Specialized Road w/Ultegra di2. What a pleasure to ride!
      Long story short:
      What I’ve learned during brief ownership:
      If it works, don’t mess with it 🙂

    2. The only way you will be able to get that type of shifting would be to buy Sram E-Tap, and put up with a slow shifting system, compared to Di2. That cant be programmed from the Shimano E-tube project software for Di2… Not sure why you would want that but there are many things that puzzle me.

    3. Di2diy is correct.
      Having reconfigured Shifters of disabled Paralympians where the aim was to assist non-orthodox configurations we are limited to the software/switch variables.

      is not clear what advantage there would be of simply toggling the FD up/down with a single switch when both limbs are functional.

      The current variables are arguably more advantageous [re one switch up and another down]. At least you will know exactly where you are without having to check before switching.

      1. Thanks for your replies. The reason is simplicity. I hate the Shimano brake lever shifters. The middle button is hard to find, especially with full finger gloves. Right hand always easier, left hand always harder is an easy concept, no thinking or reaching required. Changing the front is infrequent, too bad Di2 can’t be done like SRAM.

        Here’s the thing: Shimano designed the break shifters to be like mechanical. I get it, they wanted people to have something familiar. BUT, buttons open a whole new world of possibilities. Think “what is the most effective way to shift”, not “how do we make it mimic mechanical”.

        My two cents, thanks for reading this far if anyone still is. Appreciate your earlier replies.

        1. For you there is an was solution, buy E-Tap.

        2. Unless you have hands like a Troll the Shifter switches are designed to be easy. You can adjust the Shifters to suit your reach and pressure.
          You can also use the R600 Switch and position it on your bar where you want. These [using the E-Tube software] can be configured to shift the FD and are very easy to operate. You might want to look at that. Some guys [allegedly] have disassembled the R600 switch and siliconed those to suit their shifting choice. Have a go, it is much cheaper than buying E-Tap!

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