How to add Bluetooth connectivity to your Shimano Di2 bike

It’s now possible to add Bluetooth connectivity to your Di2 bike and this post is to tell you how and why you might want to do this.

Those of us with Di2 groupsets might not be aware that Shimano are rolling out regular firmware updates as they fine tune and add further functionality to their Di2 platforms. Like any piece of electronics with firmware, it’s generally better to be on the newest version – particularly if you like the idea of new functionality being added.

During 2016 there have been regular updates and to be honest, I hadn’t been keeping up. Previously the best way to update was to use the workshop product designed for mechanics to use (the SM-PCE1) and this is still the most complete method, but it’s an expensive item for occasional use. Another option is to use the internal battery charger (SM-BCR2), which is cheaper but can’t do any trouble shooting. I’ve also found the BCR2 a bit hit and miss at doing firmware updates.

Earlier in 2016 Shimano announced a wireless functionality update including Bluetooth connectivity to enable new features. At a starting point, this functionality allows users to use the new Shimano e-tube iPad app to update firmware, tune shifting – including the new multi-shift feature, error check or add pre-set shift patterns. This functionality is backwards compatible too – so anyone with a Di2 groupset can get this updated ability.

To add Bluetooth and allow for the future capabilities, you need to add two parts for your Di2 groupset.

  • The new EW-WU101 wireless/Ant+/Bluetooth unit which enables wireless connectivity. There is an older model – make sure you don’t order this one: SM-EWW01 – as it doesn’t have the Bluetooth capability.
  • If you have an internal battery, you need this new model: BT-DN110 or a new battery holder if you’re running an external battery. The updated battery holder is available in short or long The reason you need these parts is that they’re where the memory for Di2 is stored and they need more memory for new features.

If you’re not already running a wireless sensor, you’ll need an extra cable to add in the new sensor. I used a 150mm cable.

Installing the parts

My bike already had the old wireless sensor on the drive side rear seatstay just up from the rear derailleur. My external battery mount is on the non-drive-side chainstay. To replace both units was a very simple job. Firstly I made sure I removed battery and power to the bike, then I un-clipped the Di2 wires from both the battery holder and the existing wireless sensor. The new EW-WU101 sensor is exactly the same size and shape as the old sensor, so it was a 20 second swap over. Swapping battery holders was only slightly more time consuming as all I needed to do was unscrew the two 2.5mm allen head screws to remove and then remount the new battery holder.

It was all done in about 5 minutes. I connected the battery onto the bike – the green light came on at the junction box and the shifting worked exactly as it had.

Connecting to the new e-Tube iPad app

This was where things got a bit trickier as I experimented via trial and error to get connected. Now that I’ve figured it out, here’s what you need to, to make it much simpler for you.

  • Make sure you have the Shimano app installed and running on your iPad (obvious I know), with Bluetooth switched on
  • Make sure you’re Di2 system is all connected together and working
  • Press and hold the button underneath your junction box (the one you use to switch into gear trim mode). Only press the button for about 1 second – if you hold it for longer and go into gear adjustment mode – do it again.

  • You then should see the EW-WU101 sensor pop up on your iPad screen. Then click connect to it and you’ll get a pop-up window asking you to put in the default pairing code of 000000.
  • You’ll then be asked to change the default pairing code, which frankly worries me as I’m unlikely to remember it. I’ve written my code on the instruction sheet that came in the box (and I’m keeping the box).
  • At this point you should be connected and the app will look for firmware updates. On my bike it found three and I choose to update all devices.

When I was going through this process between point 5 and point 6, I got an error code. This caused a few problems as then the app kept telling me the pairing code was incorrect, whilst not letting me fix it. To fix this I went into the iPad setting menu, looked for Bluetooth connected sensors, found and deleted the EW-WU101 and re-added it. This fixed the problem.

Easy firmware updates and customization

Once you’ve got this far, you’ll most likely have updated your firmware and that’ll be a piece of cake going forwards.

I also had the opportunity to change which shift buttons do which functions and also the ability to add multi-shifting to the rear derailleur – like you can have with Campagnolo shifting. For now, I’ve not played with this but the option is there.

Future Di2 updates:

The one feature I was looking for that wasn’t there (as yet) was synchro shifting. It’s available on Shimano’s Di2 mountain bike groupsets and it’s coming to the road ones too – but it’s not quite yet. I’m excited about this as I tried it at the new Dura Ace launch and it was very cool indeed. If you have added Bluetooth to your Di2 bike, you’ll be unable to take advantage of new features like this easily as they become available. Making the investment in the new components will help you keep your Di2 bike (regardless of version) updated with the very latest features.

Early in 2017 there will also be iPhone and Android versions of the Shimano e-Tube apps. We should see more features added around this time.

I’ll write about any further updates as they’re released and as I try them.

If you’d like to check out Shimano’s own announcement on these new products, it’s here.

Any questions, please leave a comment.

Thanks for reading.


  • Gtran1

    I have 2016 Trek Madone and I believe it has Shimano Dura Ace 9070 Di2 system and the Junction Box SM-EW90-B.
    After I installed the EW-WU101 to the rear derailleur (all wires are firmly engaged: click sound was heard), the Green LED (Battery Check) on the junction box could not be turned on and the shifting mechanism was disabled. After I removed the EW-WU101, all things went back to normal. My EW-WU101 is brand new.
    Would you please shed some light on my issues? Your help is truly appreciated.

    • girodilento

      Hello, it may be that you also need to update your battery (or at least check it’s the BT-DN110). I had to swap both to get this update. It could also be that the EW-WU101 is running a different firmware version than the rest of your bike. Did you try to connect to your iPad? I’ll send your query to my contact at Shimano to see if they can advise (but it might take a couple of days given the holiday period).

      • Gtran1

        Hi girodilento, after I connected my laptop with the bike Di2 junction box, the eTube let me know that I have SM-BTR2 battery which is not compatible with EW-WU101. It requires BT-DN110.
        Thank you so much for your help. Happy New Year to you.

  • bernithebiker

    Good article! I just installed the new EW-WU101 and battery DN110. It was highly problematic, 1st the passcode thing, which is silly, then firmware updates for both the new parts, which both failed and said both were faulty. After persistence, I managed to get it all working, but not before a total system lock up.

  • Robbie Ferrito

    Hello Scott, thanks for this and so glad I found this blog post. I was stuck in that same place, between point 5 and 6, got the error code because I was able to change the passcode but then it didn’t like it. Followed you instructions and got it sorted. It all works perfectly now! One quick question for you, might be a stupid one but can’t find the answer anywhere. How does the EW-WU 101 unit get charged? Is there a small internal battery in it? Is it charged somehow wirelessly? I mean … I don’t want to take the risk of that being out of charge one day …. the Di2 I charge it from the junction box, connecting it to the computer or to the wall plug (even if my Planet X is brand new, so I should be good for 800 miles I heard), but at least that I can check the green light in it for make sure it’s charged … but how about the EW-WU 101? I just don’t want to take the risk of being stuck in the middle of a ride if the EW-WU dies suddenly. Thanks

    • girodilento

      Hi Robbie, glad the post helped you. The EW_WU101 gets charged via the Di2 battery – it’s charged over the wire while you’re battery is plugged in. Battery life is very good with Di2 so you’ll get plenty of mileage between charges (depending on how much gear changing your doing – especially the chainset). cheers

      • Robbie Ferrito

        Perfect! Appreciate the prompt reply, thanks again!

  • popchart

    Tried to fit the Bluetooth device to my existing DI2 road bike but was unable to ‘discover’ it with my iPad, an iPhone or someone’s Android phone all running the new E-Tube app. I was able to get the unit to talk to my Garmin 1000 unit. I guess it is something simple but has me stumped at the moment. When told the iPad to look for new devices I tried pressing the DI2 button on the bike display which soon switches off the display (as usual). I also tried operating one of the shifters to keep the display unit lit but again no luck. Remove the unit from the bike at which time the Gamin ceased to rive data which suggests that the Bluetooth device had been ‘talking’ to the Garmin. The iPad was able to detect a number of Bluetooth devices in the area. Any thoughts on what I am doing wrong?

    • girodilento

      Hi there, can you confirm which model wireless adapter you’re using and the model of your battery? Only the new model wireless adapter listed in the blog will work with Bluetooth (EW-WU101). The older model would connect with a Garmin via Ant protocol. Thanks for the comment.

  • Myeong Don Joo

    Hello. I have a problem during updating BT-DN110. The process of updating firmware was failed. After that , the battery was out of order. Would you tell me how to fix it . I tried to do test another battery. It is working good.

  • Leo Zick

    Hi there
    Great write up! I am having a small problem getting this to work. Do you know what junction box you have? I am using a SM-EW67-A-E and getting compatibility issues. With the new battery unit and this junction box, without the Bluetooth unit installed it won’t shift. With all parts connected I get a Bluetooth compatibility error,and no shifting. Not sure if I have an outdated junction box. Appreciate any help!

    • Pju

      If you look at the E-TUBE compatibility chart – I can see only : SM-EW90-A/B is supported.
      Means that SM-EW67-A-E is NOT supported.

      I was not aware of this issue – and was close to order the parts in the top of this blog.

      You find the E-TUBE compatibility chart here :

      • Leo Zick

        Hey there- agreed! I ordered the new junction as well. The charts are misleading. Here is another version that, in page 3, shows the ‘a-e’ unit could work. Their notes just don’t indicate this would only be for ant+ and the older battery.

        FYI the new battery and old junction box, without the Bluetooth module, aren’t compatible either.

        To note, there is a small internal junction box as well. I’m hoping this is just a splicing point and not another factor.

        • girodilento

          Hi there, just to confirm I am running the old junction box EW-90A and it works perfectly with the new battery/external mount and bluetooth adapter.

          • Leo Zick

            hello, and thanks for the reply. it seems that is the newer version of the SM-EW67-A-E. The A-E is hard wired. The 90A allows you to add 3 wires to it. the 90B allows for 5. I should have it Wednesday to test.

    • girodilento

      I’m running the SM-EW90-A with the components listed in the blog and it’s working perfectly

    • girodilento

      I’ve checked with Shimano and the SM-EW67-A-E isn’t compatible with the new battery so can’t be used with the Bluetooth adapter

      • Leo Zick

        thanks for following up! I received the SM-EW90A in the mail today, and wired everything. Worked perfectly. But – good to know that for those who have an older junction unit, you need to include the newer one in order for this to work. Also to note, you can hide the bluetooth unit anywhere in the bike, it doesnt need to be at the controller or derailleur.

  • Juan Delgado

    I haven’t been able to make the parts work. Initially, the app was not compatible with both, the D-Fly unit and the battery pack. I had to update the firmware using a PC direct connection (which was an inconvenience since I’m an avid MAC user). Now, I was able to update the firmware BUT the system now says the SM-BTR2 is not compatible. This is the internal battery pack that the Giant TCT Advanced Pro 1 Disk comes with. My question is, do I need then to replace the internal battery with the BT-DN110 for the system to work? Is there a “firmware update” that can save me the $110 that this battery costs?

  • Juan Delgado

    Oh, by the way, great write up! You are the ONLY blog that really helped me with this

    • girodilento

      Hi Juan, glad you’ve found it useful! I’m sorry to give you bad news but for internal battery bikes you need to have the new BT-DN110 battery as Shimano put extra “memory” in that one for the new features. You can’t run the new features on the old battery I’m afraid. For external batteries like my bike, you only need to change the battery mount (which I did).

      • Juan Delgado

        Many thanks. I have ordered the pack on Amazon. I will have a used SM-BTR2 for sale if anyone is interested!! Lol.

  • RedCab

    Here’s a tip to share based on my experience earlier today… I set about to upgrade my (new) 2017 Specialized Roubaix Di2 to bluetooth so I could do wireless updates. Ordered the new battery BT-DN110, EW-WU111 (bluetooth transmitter) and EW-SD50 (15 cm wire). Removing the battery from the seat post was much more of a hassle than I thought it would be because the “upper” rubber pushing was really holding the battery tight (hint: needle-nose pliers to pull the battery out enough to pull further with fingers. Once I got it out, I unplugged the old battery and plugged the new battery with the EW-WU111 in-line using the new wire.

    I then tried connecting bluetooth. Easy: Click “Bluetooth LE connection on ipad/iphone app, then hold button on control unit for 1 sec… red/green lights flash and ipad/iphone then identifies EW-WU111 and gives you the opportunity to connect to it. The order wasn’t intuitive for me.

    First try downloading firmware aborted midway. Tried reconnecting. Got errors on the next 10 tries. Getting frustrated. Errors say something about the battery not being charged, but I’ve got it plugged in. More frustration.

    Then I took a close look at the “old” battery and noticed my bike had the “right” BT-DN110 battery all along!!! So I plugged it back in and continued along my way with all the connections now working. I’m not sure why the “new” battery wouldn’t connect (no power? not!) but I’m sending it back.

    Now here’s the moral of the story. The EW-WU111 unit can go ANYWHERE in-line in the system. My recommendation to future readers is to FIRST install the wireless unit directly to the control unit before you open up your seat tube. Try connecting. If it works, you already have the right battery! Just pull the seat, connect the EW-WU111 and push it into the frame seat tube with out having to remove the battery from the seat post. There, what took me at least an hour should take you less than 10 mins! Cheers.

    • girodilento

      Hi Redcab, thanks for the comment. Yes, if you have a 2017 or newer model year bike you’ll most likely have the correct battery and will just need to add the EW-WU111 onto the bike and go from there.

  • RedCab

    I’ve got a couple flow up questions as I’ve now ridden my Di2 setup a few times:

    1) the rear derailler stops working intermittently. I opened the app at that time and it can’t find the RD so I’m thinking it’s either a bad wire connector or more likely a issue with the junction box. Ever have a similar issue?

    2) I’m totally confused on programming full sync and semi-sync modes. Is there a good on-line reference that can explain what I don’t find intuitive in the app?

    3) It appears that you can have 2 shift modes on the bike at one time. That makes no sense to me. (I guess that should be 2b).

    4) When I set my cassette to 11-25 I get a red ! mark (in the app). When I change it to 11-28 the exclamation mark goes away. Why?

    Anyway… any insight appreciated!!