Shimano Ultegra and Dura-Ace Di2 Electronic Shifting – Everything You Need to Know

Shimano Di2 Time Trial Triathlon GroupsetI learned quite a bit about Shimano Di2 when I installed one of the first available Time Trial/Triathlon groupsets on my Cervelo P2. I’ve subsequently answered a lot of questions on forums and article comments, and elsewhere. In doing so, I realized that people have a lot of questions about Di2 and the answers are difficult to find. This lead me to create this article, to consolidate everything I know and have been asked into one location so people can find answers. If you can’t find what you’re looking for below, please leave a comment and I’ll do my best to help.

Index: There’s lots of info in this post, so here’s an Index to help you find specific sections:

System Overview: Shimano Di2 Dura-Ace 9150 and 9070 and Ultegra 6770 and 6870

The second generation Shimano Ultegra 6770/6870 and Dura-Ace 9070  “E-Tube” electronic bicycle shifting systems consist of battery-powered electric derailleurs activated by handlebar mounted push buttons.  Power and shift commands are sent via a 2-wire CAN (Controller Area Network) datalink contained within a single cable housing. This design has several advantages over conventional mechanical shifting systems, the most notable of which are:

  1. Extremely low shifting effort, which generally results in more frequent shifts and therefore better gear ratio selection.
  2. Greatly improved shift quality, especially for the front derailleur chainrings, allowing shifting under full power with almost no chance of a dropped chain.
  3. Shifting is available at multiple positions on the handlebars, for example, at the end of the time trial aero bars, on the brake levers, up to in climbing position, and down low the sprint position.
  4. Automatic trimming of the front derailleur position as the rear derailleur moves back and forth between the smaller and bigger gears.  This eliminates unintended contact (and noise) between the front derailleur and the chain.
  5. Lighter weight vs. equivalent mechanical system. The Shimano Dura-Ace Di2 9070 electronic groupset with internal battery weighs 2047 grams; the Shimano Dura-Ace 9000 mechanical groupset weighs 2074 grams (27 grams more than Di2.)
  6. Multi-Shift: Pressing and holding a rear derailleur shift button results in shifts through multiple gears. The rate of shifts can be configured using the PC computer interface cable and the free Shimano E-tube Project software.
  7. Synchronized Shifting: Starting with Dura-Ace 9150, automated Synchronized Sifting of the front derailleur is an option. Two SHIMANO Synchronized Shift modes will be available:
    • Full SHIMANO Synchronized Shift: the front derailleur reacts based on the rear derailleur’s shift action. This essentially means that, when activated, there is no need for two separate shifters to control front and rear derailleurs, the two buttons on one shifter will control both derailleurs.
    • Semi SHIMANO Synchronized Shift mode: the rear derailleur reacts based on the front derailleur’s shift action, shifting to the next most appropriate rear gear when the rider makes a front shift.

Shimano_di2_Wire_ComparisonHistoric Info on the older first generation 5-wire Shimano Dura-Ace Di2 DA-7970 system and how it compares to the new E-tube 2-wire system:

Released in 2009, the 7970 operated using a very basic 5-wire electronic system. Each shift button was connected to a different wire; shorting the specific wires together controlled the derailleur upshifts and downshifts. Because the first generation 7970 used completely different technologies than the newer 2-wire systems, none of the components are cross-compatible. At this point, Shimano is not expected to offer any updates or new components using the first generation 7970 architecture; everything from now on will be based on the newer 2-wire E-tube design. The second generation design offers several advantages, which include: 1) smaller wire size, smaller connector size, waterproof connectors; 2) all switches can be reconfigured in software to send upshift or downshift commands to either the front or rear derailleur; 3) firmware updates can add new features (such as multi-shift) and compatibility with new components.

Compatibility: Dura-Ace 9070 and Ultegra 6770 / 6870 (and old 5-conducter 7970)

The confusing naming system used by Shimano makes it difficult to figure out what each component is, much less what is compatible between systems. Here are some compatibility guidelines:

  • 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.
  • In general, every electronic Di2 component is compatible between the Ultegra 6770, 6870, and Dura-Ace 9070 systems (see exceptions below.) This means that all of the road bike Ultegra/Dura-Ace dual control brake levers/shifts, time trial shifters, and climbing shifters can be used with either Ultegra 6770/6870 or Dura-Ace 9070 front and rear derailleurs. Any of the Ultegra/Dura-Ace controllers (A Junctions) can be used with either system. All components use the same cables and connectors.
  • Firmware Update Required to Make Older Components Compatible with Newer Components: If you add a new component and it doesn’t work, update the firmware using the PC USB adapter and the Shimano E-tube Project Software for Windows.
  • Synchronized Shifting and Bluetooth Wireless Units can be added to all E-tube Ultegra and Dura-Ace systems but the battery has to be upgraded to the BT-DN110 Internal Battery or BM-DN100 External Battery Mount. To add Bluetooth capability, a EW-WU101 or EW-WU111 inline transmitter must be added to road bikes and for mountain bikes, the SC-MT800 or SC-M9051 display/transmitter unit must be added.
  • Compatibility Exceptions:
    • Note 1 – Sprint Shifter Exception: The Sprint Shifter is the only exception for shifter incompatibility. It has a different wiring connector (and internal components) that can only plug into a unique/dedicated third port on the Dura-Ace ST-9070 Dual Control Brake Levers/Shifters and also the ST-6870 Levers. There is no sprint shifter port on the ST-R785 Hydraulic Levers.
    • Note 2 – Can’t mix 10-speed/11-speed front/rear Derailleurs: It is no longer possible to use a 10-speed front derailleur with an 11-speed rear derailleur (and 11-speed front with 10-speed rear.) See note farther below to read the history on this if you want all the messy details.
    • Note 3 – Front A junction and Internal Battery: Since the February 2015 firmware update, the older SM-EW67-A-E Front Junction A is no longer compatible with the BTR2 Internal Battery. The SM-EW90 Front Junction (with integrated charging port) should be used instead. The SM-EW67 still works with the external battery.
    • Note 4 – Update the Firmware to make components compatible: If the firmware on all components is not updated to the latest version, some components may be not operate correctly with one another. So download the latest E-tube software and update everything and it should work.
    • Note 5 – All Shifters work with all 10-speed and/or 11-speed Rear Derailleurs: All of the shifters are compatible with either the 10-speed Ultegra 6770 or 11-speed Ultegra 6870/Dura-Ace 9070 systems as long as they all have the latest firmware. The rear derailleur is the only component that “knows” or “cares” how many rear gears are available. The shifters only send upshift/downshift commands and do not “know” or “care” which gear is currently selected and how many total gears there are.
    • Note 6 – SM-BTR1 External Battery and SM-BMR1 Mount firmware updates: The more expensive dedicate service tool (SM-PCE1 PC Interface) must be used to upgrade the firmware on the external battery/mount.The external battery and battery mount can not receive firmware upgrades via the SM-EW90 Front Junction A and the SM-BCR2 PC Interface/Battery Charger. (The SM-EW90 will work in a system with an external battery, but a firmware update can cause them to become incompatible until both are updated independently using the appropriate PC Interface and the Shimano E-Tube Project software.)

Compatibility: 11-Speed Rear Derailleur and 10-speed sprockets/wheels

The 11-speed Dura-Ace 9070 and Ultegra 6870 rear derailleurs are designed exclusively for 11-speed rear sprockets and 11-speed Front Derailleurs. Shimano does not provide a way to recalibrate/reprogram them for a 10-speed setup. The sprocket spacing is slightly smaller and the overall range of travel slightly longer on 11-speed systems. If you have 10-speed wheels and 10-speed sprockets, you should use the 10-speed RD-6770 rear derailleur and a 10-speed FD-6770 front derailleur.

Similarly, a 10-speed RD-6770 rear derailleur should not be used with 11-speed sprockets. There will be chatter in some gears, and there might be slow-shifts or self-shifts.

It doesn’t matter which shifters are used; the shifters send upshift/downshift commands regardless of which derailleur config is being used. Shifters do not “know” or “care” which gear is currently selected and how many total gears there are.

Front Chain Rings: In general, most any front chain rings will work, rigid forged rings work best with Di2 due to high front derailleur shift forces. Shimano chain rings tend to be the best, but most others work as well. A 10-speed specific or 11-speed specific chain should be used, but the differences between them are minimal and can generally be mixed/matched without issue.

How to convert “non-upgradeable 10-speed only” wheels such as Zipp 900/Sub9 Disc Wheels to 11-speed: “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.” via

But it’s an emergency and I need to use a 10-speed wheel. . . In emergency situations, 11-speed rear derailleurs can be used with 10-speed sprockets. There will probably be chatter in some gears, and there might be slow-shifts or self-shifts. To setup an 11-speed rear derailleur for a 10-speed sprocket setup, adjust the mechanical limit screw so that it can’t shift into the missing 11th sprocket position, then follow the rear derailleur adjustment procedures listed below.

Included for very motivated individuals only: 10-speed front derailleurs can be used with 11-speed rear derailleurs if the shifters and battery have firmware installed from E-tube software version 2.5.2 or earlier. Shimano disabled support for this 11-speed and 10-speed cross-matching with later firmware updates. For informational purposes only, the details of how to regain compatibility are detailed below.

  • Important Notice 2014-07-14: There is a compatibility issue with Shimano e-Tube software/firmware versions v2.6.0 and later 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 or later if you are mixing an FD-6770 front derailleur and a RD-6870 11-speed rear derailleur, or a FD-6870 with a RD-6770.
    • The problem component is the battery (external battery mounts SM-BMR1 and SM-BMR2, internal seat post battery  SM-BTR2.) If you keep battery firmware at v2.0.6 or earlier, the system will continue function properly.  Shimano e-Tube Software v2.6.0 will update battery firmware to v3.0.5, and will not allow the RD-6870 to work with a FD-6770 setup.
    • If the battery firmware is updated to 3.0.5, it CAN NOT be rewritten back to the older version. You will need to need to replace a derailleur so that both are 6770 10-speed or so that that both are 6870 11-speed. (The other option is to get get a battery with the older firmware and never update it.)
    • Here’s a link to the “last known good version” of the Shimano e-Tube software to work with a mixed 10-speed/11-speed system: Use this version and do not connect to the internet when using it so that E-tube can’t check for updates when open.
    • To roll-back newer versions of battery and shifter firmware, install E-tube version 2.5.2 and made a copy of “C:\ProgramData\E-tube Project\FW” which has all the firmwares packaged in that version of E-tube. Next, install the latest version of E-tube. Then copy all the firmwares from the the 2.2.3 version back to the same location “C:\ProgramData\E-tube Project\FW” for the latest version. Next, the trick is to find the firmware you want to downgrade (pretty easy from the name and version in the file name), and then rename it to the same name as the latest version, but increment the last version digit by one. Then connect to the bike with E-tube (without an internet connection) and it will identify that a firmware upgrade is available for that component and allow you to do the firmware “upgrade” to the older version of firmware. Now exit E-tube and then rename the firmware file back to original to prevent issue in future. E-tube will then try to upgrade again but just don’t let it do that. This should get a bike that did nothing (not even enter adjustment mode) to a fully working state by reverting the battery and shifters. Running latest firmware in derailleurs seems to be fine. (thanks to commenter vosadrain)
    • It will not be possible to charge the BTR2 internal battery using the BCR2 USB charger unless you also downgrade the firmware of the BCR2 USB charger as well.
    • Note however that latest E-tube software will say the setup is unsupported and will not allow programming. To do programming, disconnect the internal battery and connect a spare external battery. This allows making settings changes. To program the BTR2 itself, I just connect to the BTR2 by itself (no other components) and the E-tube software will allow firmware changes to it. Or try using the 2.5.2 version of E-tube.
    • Alternatively, buy a Di2DIY internal seat post battery kit and you will not have to go through the firmware downgrading. The kit makes it possible to run all components with the latest E-tube firmware. Also worth noting some firmware updates were done to fix power distribution errors in the FPGA’s that would allow the batteries to drain down when the bike was just sitting.

Checking Battery Charge Level:

A single battery charge should give at least 1500 miles of riding. Most riders will not need to charge the battery more than twice a year.

To check the battery charge remaining, press and hold any shifting switch for 0.5 seconds or more. The amount of battery charge remaining will be indicated by the light on Front Controller A Junction.

  • 100% remaining: Illuminates green (for 2 seconds)
  • 50% remaining: Flashes green (5 times)
  • 25% remaining: Illuminates red (for 2 seconds)
  • 0% remaining: Flashes red (5 times)

When the battery charge is low, first the front derailleur will stop operating, and then the rear derailleur will stop operating. When the battery charge has been fully spent, the derailleurs will be fixed at the last gear shifting position. If the battery indicator is illuminated red, it is recommended that you recharge the battery as soon as possible.

Adjusting the Rear Derailleur Trim:

If you switch between multiple rear wheels, it’s very likely that the sprockets on different wheels won’t be in exactly the same relative position to the rear derailleur, resulting in that annoying clicking sound as the chain makes contact with an adjacent sprocket. Follow the steps below to properly align the rear derailleur with the rear sprockets.

  1. Shift the rear derailleur to the 5th sprocket position. Press the button at the junction (A) of the SM-EW67-A-E until the red LED illuminates in order to switch to rear derailleur adjustment mode. Note that if you keep pressing the button after the red LED has illuminated, protection recovery operation will begin.
  2. If shifting switch is pressed once while the initial setting condition is active, the guide pulley will move one step toward the inside. If shifting switch (Y) is pressed once, the guide pulley will move one step toward the outside.
    • Note: The guide pulley can move 15 steps inward and 15 steps outward from the initial position, for a total of 31 positions.
    • Note: When adjusting, the guide pulley will overrun slightly and then move back in an exaggerated movement so that you can check the adjustment direction. When checking the positions of the guide pulley and the sprocket, check at the position where the guide pulley finally stops.
  3. While turning the front chainwheel, operate shifting switch to move the guide pulley toward the inside until the chain touches the 4th sprocket and makes a slight noise.
  4. Next, operate shifting switch 4 times to move the guide pulley toward the outside by 4 steps to the target position.
  5. Press the button at junction (A) until the red LED turns off in order to switch from rear derailleur adjustment mode to gear shifting mode. Shift to each gear and check that no noise is generated at any gear position. If fine adjustment is needed, switch back to adjustment mode and readjust the rear derailleur.
  6. Note: if you have customized your shifters and swapped buttons, this will change which shifter and buttons control the micro-adjustments. Also, if you hit the wrong buttons while trying to set the FD trim, you can actually alter the setup of your RD. Be certain that you’re hitting the correct adjustment buttons.
  7. If you have a Garmin or similar head unit and a SM-EWW01 ANT module, the display will automatically switch into derailleur trim display when you activate that mode (i.e. by pressing the button at the junction (A) of the SM-EW67-A-E.) It will give you the trim position in either + or – 12 positions. When switching wheels, simply take note which position suits which wheel/sprocket/trainer, and trim to that level each time you change. This removes the guesswork and makes changing from wheel to trainer simple.

Note on FD-6870 Front Derailleur Trim:

The FD-6870 trim adjustment effects the auto-trim positions. The adjustment feature is accessible via either the A-Junction box, or the “Front derailleur adjustment setting” in the e-tube software, and should be used only after you have already set the physical inner/outer limit screws. So for example, if the FD outer plate rubs the chain when using the 6th largest cog, you would want to adjust the FD trim outward a couple ticks. However, you can only perform this adjustment while in the big-ring/big-cog combination. Etube forces the derailleurs into this maximum cross-chained position, whereas during the manual method you must shift to these positions yourself. (Thanks to commenter Bryan B for the info.)

Dealer Manuals:

The dealers manuals contain the most detailed information available from Shimano. If you’re looking for detailed installation instructions, check here:

Shimano E-tube Project Configuration and Firmware Update Software for Windows:

Shimano E-tube Project Wireless for iOS and Android: Announced on April 15, 2016 but as of yet unreleased, these apps will allow configuration of shift profiles (multi-shift on/off, multi-shift delay between shifts, shifter button assignments) and firmware updates over Bluetooth. To function, a Shimano Di2 Bluetooth Adapter, such as the MT800 digital display, is required.

Shimano E-tube Project Windows PC Software: This free software is used to update the firmware of all components. It works with the SM-BCR2 Charger + USB Adapter and the SM-PCE1 Diagnostic Adapter. The software is used to change the configuration of each shift button / lever (any can be programmed to upshift or downshift either the front or the rear derailleur.) It can also be used to enable multi-shift (multi-shift is where the shifter is held and the rear derailleur shifts through multiple gears until the shifter is released.)  The delay between of the gear changes during multi-shifting can also be adjusted. The software is available from
Older versions of the e-tube software are available from these links: 2.5.2

PC & Mobile Interfaces, Chargers, and Software:

SM-BCR1 Battery Charger: This is used to charge the external battery. The part number for the battery charger wall cord is SM-BCC1.

SM-BCR2 Charging and PC Connection: for SM-EW90-A 3-port and SM-EW90-B 5-port A Junctions. This plugs into a special port on the side of the A junctions (which is covered by a rubber flap.) This adapter charges the internal battery when first plugged into the A junction; it must be powered by a standard USB Wall charger (such as that used for an Apple iPhone) or a PC that is powered-on. If the Shimano E-Tube Project Software is launched on the Windows PC with the SM-BCR2 attached, the SM-BCR2 will switch from charging mode to configuration mode. It must be detached from the computer and reattached to switch back to charging mode.

  • It takes about 2 hours to charge the internal battery.
  • Amber light=charging.
  • Light turns off when done.
  • If the Amber light does not come on when plugged in, this indicates battery is not discharged enough to charge.
  • Light flashing indicates something is wrong, like trying to charge a external battery through a BMR.


Shimano_di2_junction_a_charger_pc_interface big

Junction A Charger Port and Charger/PC Diagnostic Cable

Hacking the SM-BCR2 to have a standard Di2 cable connector: If your 3-port or 5-port junction is inaccessible for charging, there is an alternative hack method to connect it to the system through a standard Di2 port. With basic soldering skills you can hack the BCR2 to be used with any setup. Buy any length EW-SD50 wire, cut off one end. Cut the wire on the output side of the BCR2. Splice the two wires together, so that the output wire of the BCR2 is now a standard Di2 connector.  The charger has an inner (white) and outer (shield) wire; connect the inner white wire to the  SD50 red wire; connect the charger outer shield wire to the SD50 black wire. You will then be able to plug the BCR2 into any Di2 port . Or use a SM-JC40 junction B and another length of EW-SD50 wire and go through the RD (by using the SM-JC40 to connect the rear derailleur, new output wire of the  EW-SD50 , and the wire that ordinarily connect the rest of the system to the rear derailleur.) Thanks to @Di2diy for the info.

SM-PCE1: This PC Configuration and Diagnostics adapter will not charge the internal battery. It offers the same configuration options as the SM-BCR2, but also add some advanced diagnostic and troubleshooting features that the SM-BCR2 does not have. It attaches to via the standard E-tube wire (just like the EW-SD50 cables) rather than to a dedicated port on the side of the front A junction.

Bluetooth and E-tube Apps for Apple iOS and Android: Bluetooth wireless modules are available to allow system settings to be adjusted via the mobile applications that connect via Bluetooth Adapters.


Component Overview:

The confusing naming system used by Shimano makes it difficult to figure out what each component is, much less what it does and how it fits into an a complete Di2 system. Here’s an overview of all the major Ultegra and Dura-Ace Di2 components.

Dual Control Brake Levers/Shifters (a.k.a. Brifters):

ST-6770 Ultegra Road Dual Control Brake Levers/Shifters: The Ultegra version can be used with the climbing shifters. They are sold in in left/right pairs and are also available separately.

ST-9070 Dura-Ace Road Dual Control Brake Levers/Shifters: The main advantages these have over the ST-6770 version is slightly lighter weight and compatibility with the low-mount sprint shifters. As like the Ultegra version, they are compatible with the climbing shifters. They also have hidden button under the rubber hoods that can activate screen changes on cycling computers from Garmin, Magellan, Pioneer, and Shimano (Shimano SM-EWW01 ANT Wireless Broadcast Module required.)

ST-9071 Dura-Ace Time Trial/Triathlon Dual Control Brake Levers/Shifters: These levers provide shifting from the pursuit bar position on time trial bikes. There is no Ultegra option offered at this time. These are available as left/right pairs, or can be ordered separately. These do have a permanently attached wire with a male end for connection the the SM-EW90 front “A” junction. Combined weight both levers: 117 grams.

ST-R9160 (standard cable brakes) and ST-R9180 (hydraulic brakes) Time Trial Dual Control Brake Levels/Shifters: These are the lower-profile shifters offered with the newer Dura-Ace R9150 groupset.

ST-6871 Ultegra Time Trial/Triathlon Dual Control Brake Levers/Shifters: Ultegra version of the ST-9071 Dura-Ace shifters. Slightly heavier and much less expensive than the Dura-Ace version. Combined weight both levers: 142 grams.

ST-R785 Hydraulic Road Dual Control Brake Levers/Shifters: These hydraulic road shifters are compatible with both the climbing and sprint shifters. These are compatible with the SM-RT99 centerlock 140mm and 160mm rotors and WH-RX31 wheelset (which as no standard rim brake track.) These require the BR-785 dual piston hydraulic disc calipers. They do not have the special wiring port required for the SW-R610 Sprint Shifters and a SM-EW90-B 5-port junction A is required to use the SW-R600 climbing shifter.
shimano_st-r785 shimano_r785_br-r785_sm-rt99

ST-6870 Ultegra Road Dual Control Brake Levers/Shifters: These road shifters are compatible with both the climbing and sprint shifters.

Dedicated Shifters:

SW-R671 Dura-Ace 2-Button Time Trial/Triathlon Bar End Shifters: These shifters are installed on the end of time trial aero bars. By default, the left shifter upshifts/downshifts the front derailleur; the right controls the rear derailleur. For both, the lower button upshifts into a harder gear and the upper button downshifts to an easier gear. This can be changed using the Shimano E-tube Project software; the functions of the left and right sifters can be switched with one another as well. These are available in pairs or separately.

SW-9071 Dura-Ace 1-Button Time Trial/Triathlon Bar End Shifters: These shifters have only one button each and are intended to control only the rear derailleur, with one sending the upshift command and the other the downshift command. (I personally think this version is absolutely worthless. Why have 2 SW-9071 shifters at twice the price and twice the weight, when you can just buy a single SW-R671 Right shifter instead.)

SW-R600 Climbing/PAVE Shifter: This shifter is for road bikes and is mounted on the upper horizontal portion of the handlebar, or any other location comfortable for the rider. They can be used in addition to the Dual Control Brake Lever/Shifter, or can be used on their own by plugging directly into a SM-EW90-A 3-Port Junction or SM-EW90-B Dura-Ace 5-Port Junction.

SW-R610 Dura-Ace Sprint Shifter: This is the only component using a unique wiring connector; it is only compatible with the ST-9070 Dura-Ace  and Ultegra ST-6870 Road Dual Control Brake Levers/Shifters. Unlike all of the other shifters, the sprint shifters do not contain a circuit board; they do not show up as components on the CAN bus network. Instead, the sprint shifters are simple momentary switches that activate the circuit board on the host Dual Control Brake Lever/Shifter. The host dual control lever is what sends the shift command. (Note: Any momentary switch can be attached to the sprint shifter port on the Dual Control Levers by splicing into a standard EW-SD50 wire to act as remote shifters.)

Alfine SW-S705 Right Flat-Bar Shifter: Reported to work with other non-Alfine setups.

SW-R9160 Time Trial bar-end shifters (pair): These are-end shifters directly control the rear derailleur, with one for the upshfit and one for the downshift. The front derailleur is controlled automatically via automatic Synchronized Shifting. These shifters require the BT-DN110 Internal Battery.

Front Derailleurs:

FD-6770: Ultegra Front Derailleur

FD-6870: Ultegra Front Derailleur, pretty much identical to the FD-6770 but with a slightly larger diameter adjusting screw (to better dissipate the shifting forces).

FD-9070: Dura-Ace Front Derailleur
FD-R9150: Dura-Ace Front Derailleur for 9150 systems; features slightly reduced weight vs. 9070.

Rear Derailleurs:

RD-6770: Ultegra 10-Speed Rear Derailleur, compatible with gears up to 28 teeth.

RD-6870: Ultegra 11-Speed Rear Derailleur, compatible with gears up to 32 teeth (for the GS version).

RD-9070: Dura-Ace 11-Speed Rear Derailleur, lighter weight version on which the RD-6870 is based.

RD-R9150: Dura-Ace 11-Speed Rear Derailleur with 30-tooth sprocket compatibility and modified “Shadow RD” geometry to keep the mechanism close to the rear wheel to help avoid damage in the event of an accident.

Alfine SG-S505 and SG-S705: The Shimano series targets comfort and urban bikes. It uses an 8-speed (505) or 11-speed (705) internal epicyclic rear hub. It is believed to be compatible with other Di2 ETube components but this has not been verified.

Display / Wireless Communication:

SM-EWW01 ANT Wireless Broadcast Module: This module wirelessly broadcasts Di2 data (front and rear gear selection details, gear ratio, battery life) to a cycling computer using the ANT protocol. It is compatible with Dura-Ace 9070, Ultegra 6870 Di2 and Ultegra 6770 E-tube road shifting systems. SM-EWW01 plugs into the E-tube wiring system between existing components. It has an 2 wiring ports, so it can be connected between a front shifter and the Front Junction A, or at the rear derailleur (between rear derailleur and Etube wire.) It transmits through a proprietary private ANT wireless protocol, which may eventually become a standard public ANT+ protocol. It is powered by the same Di2 system battery. It is currently compatible with the Garmin Edge 1000, Mio 505, and the PRO SCIO cycling computers (with more to come.) The hidden buttons under the hoods of the 9070 shifter levers will switch screens on the cycling computer when paired with this module. It does not currently allow for shifting control from a cycling computer/device and it is not clear that this functionality will ever be offered. The SM-EWW01 is 38mm long, 25mm wide, 12.5mm high, and weighs less than 5 grams. It does not come with any wires; 1 wire would have to be added if adding this module to an existing Di2 system.

EW-WU101 and EW-WU111 ANT and Bluetooth Wireless Broadcast Modules: These modules are similar to the SM-WEE01 but also include Bluetooth capabilities in addition to ANT capabilities. They require the BT-DN110 battery or the BM-DN100 Battery Mount and can not be used with the SM-EW67 Front A Junction.


Shimano XT Bluetooth Wireless Required Components

SC705 Alfine Display Unit: This unit displays the battery level and the rear derailleur gear selection. It is powered by the system battery and has a port for the SM-BCR2 internal battery charger / USB diagnostic tool. It is primarily designed for Alfine systems (both 8 505-series and 11 speed 705-series). It is compatible with Ultegra and Dura-Ace Di2.

MT800 Digital Display with Bluetooth: Primarily aimed at XT mountain bike applications, this display allows toggling between the 3 synchronized shift modes (where both both derailleurs are intelligently coordinated in unison by one pair of buttons, so no need for discrete shifting of the front derailleur.) It also shows battery level, gear position, shift mode and FOX iRD suspension position. The Digital Display required the new BT-DN110 battery. Existing Di2 XT systems are upgradable to be compatible with the new digital display after battery upgrade and firmware upgrade. This display has 3-port Di2 Cable junction and charging port integrated into the back and serves as a Front A Junction.
Shimano mt800 Digital Display with Bluetooth

Batteries and Battery Mounts:

The batteries contain the main controllers for the system. It is therefor required to upgrade the battery to get features released in new versions of Di2 (such as Synchronized Shifting that automatically controls the front derailleur based on rear derailleur shifting.)

SM-BTR1 External Battery: This external battery must be used with the SM-BMR1 battery mount. It is removed from the mount and charged using a dedicated charger.

SM-BMR1 and SM-BMR2 External Battery Mount: This mount attached to bottle cage mount points or other dedicated frame mounts. It is available in  3 different mount lengths: -I (intermediate length), -S (short length), -L (long length). The SM-BMR2 is an updated version of the SM-BMR1.

SM-BTR2 Internal Battery: This battery is typically mounted in the seat post or seat tube of the frame. It is charged by plugging the SM-BCR2 Charging Cable/PC Adapter into the SM-EW90-A or SM-EW90-B Front A junctions.

BT-DN110 Internal Battery: This battery is required for Bluetooth wireless units and road groupset Synchronized Shifting functionality.

BM-DN100 External Battery Mount: This battery is required for Bluetooth wireless units and road groupset Synchronized Shifting functionality.


Front A Junctions:

SM-EW67-A-E Ultegra 3-Cable Junction: This is the original front junction with 2 integrated cables to connect to the dual control brake lever/shifters. The male cable ends on this Front A Junction will not mate directly to the male cable ends on any of the Time Trial/Triathlon dual control brake shift levers or shifters; SM-JC41 Rear B Junctions can be used to connect this front A junction to TT/Triathlon shifters. This Junction works only with External Batteries, not Internal Batteries.


SM-EW90-A Dura-Ace 3-Port Junction: This front “A” junction is most commonly used in road bike setups. 2 ports connect to the dual control brake / shift levers; the third port is for the cable that leads to the bottom bracket junction.

Shimano_SM-EW90-A 3-port and Shimano_SM-EW90-B 5-port Front "A" Junctions

Shimano_SM-EW90-A 3-port and Shimano_SM-EW90-B 5-port Front “A” Junctions

Shimano_di2_junction_a_charger_pc_interface big

Junction A Charger Port and Charger/PC Diagnostic Cable

SM-EW90-B Dura-Ace 5-Port Junction: This front “A” junction is primarily used in the Time Trial / Triathlon setups. 2 of the port are for the brake/shifter dual control levers, 2 of the ports are for the aer0 bar bar-end shifters, and the 5th port is for the cable that runs to the bottom bracket (where the B junction joins the wires from the front A junction, front derailleur, rear derailleur, and battery.)

EW-RS910 Internal Bar-end Junction: This junction is installed into the end of a bar or in a dedicated frame port. It facilitates internal cable routing.

B Junctions:

SM-JC41 Internal Junction: This version has the exact functionality as the SM-JC40 external version, but doesn’t have the mounting tab for being bolted to the bottom bracket or wrapping the extra cable lengths. It has 2 ports on one end and 2 on the other, making it more compact. In addition to being located at the bottom bracket to connect the A junction, battery, front derailleur, and rear derailleur, it can be used at the handle bars to join multiple shifters prior to being connected to the A Junction.

SM-JC40 External Junction: This version is intended to be attached to the frame using the bolt that is commonly located underneath the bottom bracket housing. This junction contains no electronics; it’s sole purpose is to join 4 connectors together, which are usually the wire from the front A junction, the battery, the front derailleur, and the rear derailleur. There are wire holders above the housing to capture the extra wire length by wrapping it back-and-forth.

Cables, Grommets, and Cable Remove/Install Tool:

EW-SD50 Cables: These cables connect the front A junction, the battery, the front derailleur, and the rear derailleur to the rear B junction, which is typically located near the bottom bracket (near the cranks.) These are available in lengths of 300mm, 350mm, 400mm, 500mm, 550mm, 600mm, 700mm, 750mm, 950mm, 1000mm, 1200mm, 1400mm.

SM-GM01 Grommet: These round grommets are used when drilling round holes for internal cable routing, or with existing round holes. The required hole diameter is 6mm (6mm  = .236 inches. Use a 7/32-inch drill bit and then “wallow-out” the hole to make it a little bigger; a 1/4-inch drill bit will work but is just slightly larger than necessary.)

SM-GM02 Grommet: These 7mm x 8mm oval shape grommets are used in some situations / frame designs.

Shimano TL-EW02 Ultegra DI2 E-Tube Tool: This tool is used to connect and disconnect the Etube wires. They are extremely difficult to connect/disconnect by hand, and pliers or other tools can damage the wires. Don’t get this confused with the TL-EW01 tool, which is for the older 5-wire 7970 cables. (My Dura-Ace TT Dual Control Levers came with one of these tools, but no other components did.)

Common Questions (via Shimano):


Note: it is not necessary to replace the FD from upgrading from 10-speed to 11-speed.

What Components do I need to put together my own Di2 system?

Because of the huge number and variety of components, it’s very difficult to figure out what is actually necessary and what is optional. So here is a list, for the setup I recommend: Ultegra 6870. It starts from the handlebars and works backwards. (This assumes both front and rear derailleurs, but you actually don’t have to have both; you can pick one or the other and only the corresponding front shifter to go along with it.)

  • Any Type of Shifters / Shift Buttons. The Dual Control Brake Levers/Shifters are not required. You can get the just the climbing shifters or Triathlon/TT bar-end shifters, and then potentially add the Dual Control Levers/Shifters at a later point. (The only exception is the Sprint shifters, which require specific Dual Control Levers/Shifters with special ports as noted elsewhere in this article.) link
  • EW-SD50 Wires 1 and 2 between the front shifters and the Front Junction A (0nly for some shifters). This is a bit confusing, because some of the front shifters come with wiring attached to them and some of them require purchasing separate wires. In general, most of the stand-alone shifters come with wiring, as do the TT/Triathlon dual control shifters/levers, but the road dual control levers do not. link
  • Front Junction A. I recommend the SM-EW90-B 5-port front junction A as it provides the most upgrade flexibility; get the 3-port option only if you’re positive you’re never going to add more shifting components. The older SM-EW67-A-E has 2 wires built-in to connect with each of the dual control shift/brake levers; it doesn’t offer much flexibility or compatibility with a TT/Triathlon setup or adding additional shifters. link
  • EW-SD50 Wire 3 between the Front Junction A and the 4-port Rear Junction B connector. link
  • EW-SD50 Wire 4 between the Rear Junction B and the Front Derailleur. link
  • EW-SD50 Wire 5 between the Rear Junction B and the Battery. link
  • EW-SD50 Wire 6 between the Rear Junction B and the Rear Derailleur. link
  • Rear Junction B: This is where the wire from the front of the bike is connected to 3 output wires leading to the front derailleur, rear derailleur, and battery. SM-JC40 is for external wiring, SM-JC41 is for internal. link
  • Grommets for any place where the wire goes into the frame through a drilled hole. link
  • Front Derailleur. I recommend the Ultegra FD-6870 for 11-speed builds or the FD-6770 for 10-speed builds. The Dura-Ace FD-9070 is pretty much identical, just slightly (41g) lighter and 11-speed only. (I do not recommend the Ultegra FD-6770 unless you have a 10-speed setup, because of firmware compatibility issues with 11-speed rear derailleurs. Also, it is an older design than the FD-6870, so it is larger and offers slightly less shifting force.) link
  • Battery and Charger. Internal or external, depending on the build. If you have to skill/time/money-to-pay-someone to get everything internal, I highly recommend that option. The SM-BTR2 internal battery has more advanced integrated electronics and is better for firmware upgrades with the SM-BCR2 internal battery charger/PC tool. If you go with the SM-BTR1 external battery, you will need the SM-BMR1 external battery mount and SM-BCR1 external battery charger. link
  • Rear Derailleur. I recommend the Ultegra RD-6870 for a new build if you have 11-speed compatible wheels with 11-speed sprockets, or the Ultegra RD-6770 if you have 10-speed wheels/sprockets. The system must be match front and rear derailleurs (both 6870 11-speed or both 6770 10-speed.) link
  • TL-EW02 Etube Wire Remove/Install Tool: It takes quite a bit of force to snap the wires in/out. You may think you can get it seated properly with just your fingers, only to then have the wire come loose because it wasn’t fully seated. It’s a good idea to keep one in your saddle bag. link

What wire lengths do I need? This question is impossible to answer correctly, as it’s highly dependent on the frame size and configuration. What I recommend is running string between the component mounting locations to measure the lengths. Be sure to add some extra length, as I find that wires seem to come up short pretty frequently, even when “adding a little extra” to start with. Nothing is more frustrating that having a wire that is 25mm too short. I recommend ordering a few extra wires of multiple lengths and then returning the unneeded/unused wires. As noted above, the standard wire lengths are 300mm, 350mm, 400mm, 500mm, 550mm, 600mm, 700mm, 750mm, 950mm, 1000mm, 1200mm, 1400mm. Do not  cut/splice these wires; the connectors on the end of the wires are very small in diameter to start with and you’ll end up with a splice that is larger and less waterproof than you started with.

Acknowledgements: Special thanks to Di2diy for his continued help in the comments. Check out his Ebay store for custom Di2 batteries, harnesses, and components.

Technical Details of the Di2 CANBUS protocol and signaling

Thanks to commenter Ghislain for the details: “I reversed engineered the signal going to the RD. Since I did not have a special tap connector, I could only look at the actual signals in open loop (RD wire disconnected) on the wire going to the RD using an oscilloscope. First, I found that shift up and down are multiplexed on the same wire. A shift down would generate a positive 100 msec clean 8 volt pulse (varies between 50 msec to 500 msec depending on how long you hold the shifter). On the same wire, a shift up would generate a series of 2 msec pulses that would last the same time of a shift down pulse. Therefore, the RD has enough intelligence to discriminate between the 2 types of pulses. When you hold the button on junction A, a 140 msec pulse is generated. But since my RD wire was disconnected, the RD would not go in adjust mode.”


Written by in: Triathlon | Tags: , , , , , , , , , , , , , , , , , , | Last updated on: 2016-November-07 |


  • john jauss says:

    I think my 9070 di2 went into crash mode. I hita series of pot hole at 20mph, lost a water bottle &soon afterwards I could not shift either derailleur. I held down buttom “a” for 5 seconds & it went into blinking & then I could hear it shift & I thought it cleared itself but it didn’t. Tried serveral times with no luck. My first thought was something had become unplugged because everything was dead. In crash mode, is the front derailleur dead also. The shimano instructions say something about manually clearing it out of crash mode, but tells you to see a distributer. This is my second di2. #1was external wire 7970.both are scatantee from performance. JOHN JAUSS

  • sam says:

    In installed e tube software, but when running the connection check, there are no boxes to check “select” and it keeps telling me units other than the sm-btr2 are connected and will not update any firmware

  • ian says:

    very good article. The ST-R785 do not have a sprint shifter port. You would need a 5 port junction A box if you wanted to use the climbing shifter. See pg 31

  • Rodolfo Araujo says:

    Great article! “Front Derailleur. I recommend the Ultegra FD-6870 for a new build. The Dura-Ace FD-9770 is pretty much identical, just slightly heavier.” I think you mean slightly lighter, right? The 9070 is lighter (114g x 155g) according to reviews…

  • rgrissom says:

    Will the ST-6871 Ultegra Time Trial/Triathlon Dual Control Brake Levers/Shifters work with an Ultegra 6770 RD? Great article!

  • Vince says:

    What is the difference between the ST 9071 and ST 6871 TT dual control?

    • Carlton Bale says:

      the difference between the Dura-ace ST-9071 and Ultegra ST-6871 TT dual control levers is the same as all of the other Ultegra and Dura-Ace components. Dura-Ace weighs a little less and costs a lot more. I recommend going Ultegra and eating fewer doughnuts. 🙂

  • Martin Novotny says:

    Hi there, a stupid question… I have 2 Orbea triathlon bikes, both on mechanical Ultegra, resp. DuraAce sets (few years old – not the latest versions). Is there any difficulty to upgrade it to DuraAce Di2 9070? If not (directly), is there any tweak how to do that? Both frames are OK and I don’t want to change them… Thanks!

    • Carlton Bale says:

      Martin, I can’t say for certain on the Orbea frames, but in general, any frame can be upgraded if you wire it externally and pretty much any frame can be upgraded using internal wiring if you’re OK with drilling a few holes. I upgraded my 2008 Cerverlo P2 to Di2 internal. The big problem area is the bottom bracket. My bike has a solid bottom bracket housing, so I had to drill holes through it to pass the wires from the down-tube through to the top-tube/chain-stay cavity. I also had to drill a hole in the top tube near the head tube. Drilling carbon is pretty easy. Tape the area, use sharp bits, start with the tiny bit, and work your way up one size at a time to the required hole diameter (6mm round or 7mm x 8mm oval).

  • Don Lim says:

    Hello !, I have just bought a used Dura Ace 7970 Di2 set up and was hoping to use it on a flatbar. Can you give me any suggestions on what switching I could use? or can I take the switch out of the brake levers and design a housing for them. Thanks in advance..Don

  • mark s says:

    great article thanks. I have a Trek Domane 5.9 10 speed with battery mounted under the bottom bracket – not a clever place ! Any ride day other than dry weather and the battery + holder gets covered in sand / road grunge – gets in everywhere and jambs the battery release mechanism. So now if it looks like its going to be wet weather – i cover it over with cling film and an elastic band – which I remove at the end of the ride. Envy for those with internal battries

  • Pierre says:

    I just upgraded my Trek Madone 6.9 SSL to Di2 (9790) and have a simple question. Is there some master On / Off mode to prevent shifting in case something rubs against the shifters ? I usually put my bike in the car with some stuff over it and sometimes something may press against the shifters…


  • Geraint king says:

    How to open front junction box on di2 to replace damaged cable. Have new cable but can’t seem to open the box? Don’t know if I’m being to gentle or need to use some force?

  • jeff says:

    if i have a complete 9070 group , can i use 10 speed wheels using a 10 speed cassette

    • Carlton Bale says:

      I wouldn’t recommend it. You’d have to eliminate the 11th sprocket by adjusting the mechanical derailleur limit screw and you’d have chatter from the sprocket being slightly different.

    • You can machine 1.85mm out of the back of the cassette carrier. Works well on most wheels, you will need to check the clearance between the carrier/sprockets and the hub. Don’t adjust the limit screws to stop the throw of the rear derailleur – firstly the spacing is different between 11 speed and 10 speed sprockets, second the sprockets them selves are thinner, third the shifting when using a 10 speed cassette with an 11 speed derailleur is very poor (if you wanted poor shift quality you would have bought SRAM components) forth if you dial the limit screws in the servo in the rear derailleur will continue to “work” in the largest sprocket- low gear, the derailleur will only stay there for 5 seconds then shift to the 2nd sprocket. This is to protect the servo from over working and to stop battery drain. Same with the smallest sprocket- large gear.

  • Rodolfo Araujo says:

    Can I reprogram the actions of the sprinter buttons so that I can place them on the top of the handlebar, near the end of the bar tape and control only the rear derailleur? What I want to do is to have a climbing shifter, but without that bulky unit… I could hide everything with the bar tape. Thanks

    • Di2diy says:

      I assume you are asking about 9070 or 6870 Di2, the answer is yes but no reprogramming is necessary, the only issue is cable length. You can also set the sprint shifters up with cateye buttons and have one small button on each side of the stem right where your thumbs would be on the bar.

    • You are only limited by the length of wire that the sprint shifters come with. The sprint shifters can only be plugged into the lower port on the shifters.

      • Di2diy says:

        You can make the cable any length by sicing a section of wire, or just splice a longer e tube cable (EW-SD50) with a plug, you can use any monetary switch like cateye buttons by splicing them to a EW-SD50, one cable cut in half and two cateye buttons is all you need, of course they can only be plugged into the lower shifter plug.

        • Gerr says:

          Hi Di2diy, Just scienced out making my remote rear der. shifters by plugging into the 6870 lower right/left lever auxiliary ports (splicing into an ewsd50 wire as you mentioned.)
          Anyway to control the front der remotely ? (as cheap and easy as the rear ?)
          While I am here, what are the middle aux. ports on the levers for ?
          Thanks !!!!!!!!!!

          • Di2diy says:

            Gerr, the only way to get remote shifting for the FD is with the TT shifters SW-R671, or brake ST 9071/6871, and hack the insides, not at all easy, or reliable. The middle ports are only for the remote SW-R671 for adding TT shifters or SW R600 climbing switch… any of the above items can be plugged in anywhere in the system and need not be plugged into the shift levers, but thats what the ports are fore.

          • Gerr says:

            Thanks Di2diy, Also thanks for your time on all these various post. (Both you and Carlton). I spoke with Fairwheel Skunkworks. 😉 The 2nd generation lower ports (1 for up other for down) working with a simple N.O. switch (such as the waterproof cateye); is a default behavior left over for compatibility of 1st generation. At least that is my understanding between 1st generation analog vs second gen.
            So, only works with the rear der. as that is programmed. But, no such programming available to handle the front. But, I think I read that it is possible to program the 2nd gen. sprint shifters to control either der. So, we could plug them into the smew90-b 5 port a box or into the middle lever ports. But….then….$$. At least small…..I might be wrong on all of this but it wouldn’t be the first time or the last. 😀

        • denwol says:

          Just wondering, what size heat shrink do I need for the inner wires? Thanks

  • Donovan says:

    I have 2012 Mavic SLR wheels, can i upgrade to the new Duro Ace DI2 11 speed without having to replace my wheels?

    • Carlton Bale says:

      Donovan, I have no idea about specific wheel compatibility. You’ll need to ask Mavic if their wheels are compatible.

      • Gary says:

        Pretty sure that all Mavic wheels made since 2007 are 11 speed compatible, you just need to remove the thick spacer under the normal thin spacer from your cassette, I just upgraded my 2009 Mavic Kyserium SL with no problem

  • Richard Balshaw says:

    Hi Carlton, I have the R600 climber switch but the cable that comes fixed to the switch is just too short for my purposes. Is it possible to add an extension lead somehow?

    • Carlton Bale says:

      Hi Richard. You can extend the wire by using a SM-JC41 Internal Junction at the end of the shifter wire and connecting an additional EW-SD50 wire to one of the other junction ports.

    • Di2diy says:

      It very easy to splice that cable if you have basic soldering skills, all you need is some two strand 24 gage wire, shrink sleeve and a soldering iron.

      • Richard Balshaw says:

        Thanks Di2diy – this would certainly be the neatest method but I don’t have the soldering gear or skills so will go with the junction box method.

  • Glenn says:

    Great article, but did not really catch up with the compatibility between 10 speed Ultegra and 11 speed Ultegra rear derailleur. Are the interchangeable when using a 11 speed Ultegra shifter? Have access to the latest firmware update.

    • Carlton Bale says:

      It doesn’t matter which shifters are used; the shifters only send upshift/downshift commands and do not “know” or “care” which gear is currently selected and how many total gears there are.

      • Thanks a lot. In other Words, I have a bent 6870(11speed) rearderailleur(Chrashed i Paris-Roubaix Juniors), this might be replaced by a 6770?(10 speed)? The 6870 is hard to find around here.

  • Emerson says:

    I upgraded my bike from a 10sp Ui2 to a 11sp Ui2. I changed teh chain, sprocket and RD. However, the RD does not respont to the shifter commands. In the meantime, the FD responds normally. Do I need a firmware update? How do I go about that? I read on your comments about the older SM-EW67-A-E Ultegra 3-Cable Junction and I think I have this on my bike. How do I connect the bike to the PC?

    Great article btw. Tks in advance.

    • Carlton Bale says:

      Emerson, you need a SM-PCE1 PC adapter to update the firmware since you have the old 3-cable junction. It is somewhat expensive, but it will update the firmware and should solve your problem.

  • Emerson says:

    Tks Carlton. I am in a bit of a dillema. The SM-PCE1 plugs into the shifter, correct? I also have a TT bike with a 5-port jctn. Will I also be able to diagnose the groupset on the TT bike with the SM-PCE1? I suppose not because the 5-port jctn connects to the SM-BCR2? So, do I have to have both the SM-BCR2 and SM-PCE1 to diagnose these different groupsets?

    Perhaps a more economical solution would be to change SM-EW67-A-E Ultegra 3-Cable Junction to a 3-port jctn (SM-EW90-A Dura-Ace 3-Port) and buy only the CM-BCR2?

    Tks again.

    • Emerson says:

      One more question. I undesrtand the difference in battery charging capabilities of the SM-PCE1 and SM-BCR2 but in terms of functionality of disgnosis and updates of firmware are they identical?

      • Carlton Bale says:

        Generally speaking, they are very similar. The SM-PCE1 can do more advanced diagnostics, but they are not generally all that useful. You’re cheapest option is to temporarily install the 5-port junction on your other bike and use the SM-BCR2 to do the firmware upgrade. The only issue is that you probably can’t update the 3-cable junction that way, but not sure how critical it is for the firmware on that to be the latest version. If it is, then upgrading that junction to the new version would be your second option, and getting the PCE1 your third option (from a cost/redundancy standpoint.)

        • Di2diy says:

          Actually the PCE1 can do diagnostics on every component, although not always useful, BCR2 can only do updates (no diagnostics) and charge the BTR2. No you can’t update a EW67A if you use a EW90 with a BCR2… only one front junction can be used at a time. However if you have basic soldering skills you can hack the BCR2 to be used with any setup. Just buy any length EW-SD50 wire cut and splice it to the BCR2 than you can plug it into the shifter port, or buy a SM-JC40 junction B and another any length EW-SD50 wire… than you can just go through the RD by plugging the SM-JC40 to the RD wire and the extra EW-SD50 wire to the RD and plug the BCR2 or PCE1. This jumper setup also works better than going through the shifter port with the PCE1 as well since the shifter port is not always easy to plug into depending on how you wrap your bars.

          • Sim says:

            Hi, I’m trying to splice the BCR2 charger to a SD50 cable so I can use the old front junction with the seatpost battery.

            I have the wires cut open. The charger has an inner and outer wire while the SD50 has a black and red one. Does anyone know which solders with which?

            Sorry if this seems like a dumb questions I’m a new to soldering wires. Thanks!

          • Di2diy says:

            White to red, black to shield

          • Sim says:

            It worked! The battery charged up and was able to use the etube software. Thanks so much for the info. You’re awesome!

          • Josh says:

            I’m planning to install di2 on my shiv tt and want to put the junction hidden in the head tube. I understand I can charge by plugging an extra 3 port junction into the rd – correct?. I’m having a bit of trouble understanding whether I could daisy chain in the extra junction box and then be able to use that to adjust the rear der, etc. thanks

          • Di2diy says:

            Shimano has changed the firmware since that post you quoted. You can no longer use a BCR2 with a EW67, only a EW90. However you can still hide the A junction I prefer under the seat by drilling a hole at the top of the seat pin, and you only need one wire going to the junction. Use a JC41 up front for the shifters to the front junction wire. Most people think the shifters need to go through the A junction but that’s just not the case.

          • Josh says:

            Thanks! But if I switch the junction boxes to ew90s can I use the setup I suggested and avoid drilling the seatpost? I guess my question is whether if I have two ew90s in the system will it work to charge and adjust th RD? I’m reading conflicting things about whether the two junctions will cause problems. In the end your suggestion may be better anyway – definitely more user friendly to just plug the charger in under the seat. Sorry if I’m asking dumb questions – new to this stuff but it is fascinating.

          • Di2diy says:

            Only one Junction is allowed in the system so it won’t be recognized or do any updates with two But you can disconnect the EW67

          • Di2diy says:

            But Yes you will be able to charge through any port if you use an EW 90 and splice in a EW50 connector.

          • Josh says:

            Sorry – also if I use your seat post suggestion could I use two JC40s if I want to run shifters on the extensions and base bars but only have one wire into the junction?

          • Di2diy says:

            Yes, and you can use as many JC 41s as you want.

  • carnold says:

    On the upgrade from Di2 10 speed to 11 Speed does the 10 speed crank need to be replaced?

  • David says:

    Fantastic overview.

    Someone needs to hack an RD so it can have a 10sp/11sp toggle.

  • eric says:

    Can one use 2 sets of the SW-R671 bar end shifters? The reason I ask is I’m building up a Cervelo P5 and it has Magura hydraulic brakes and the brake levers on the drops and I’m putting one set of the SW-R671 on the areo bars and was thinking of disassembling the other set of SW-R671’s and put them next to the Magura levers on the drops. I’ve seen/read where many have hacked/soldered into the ST-9071’s for a clean P5 look. But upon investigating the SW-671’s, their insides look much easier to work on with less soldering.
    BTW, I’ve built up 3 (working on a 4th) Di2 bikes (2 road, 1 tt) and the system works flawlessly.

  • Emerson says:

    Carlton, I was under the impression that to update a 10sp Electronic Ultegra to a 11sp, all that needed to be changed is the RD and obviously the cassette and chain. I did just that and initially the rear derailluer did not respond. Then I check with you and you mentioned that I should update the firmware of all the components. I updated the firmware of all the components sucessfully but now I get no response from the front AND teh rear derailleur. In addition I got an error message on the e-tube project software that teh FD6770 cannot be used with the RD6870. Just to be clear, my set up is as follows: SM-BMR1 (battery holder), ST-6770-L and ST-6770-R, SM-EW67-A-E, FD-6770 and RD-6870-GS.

    • Di2diy says:

      I have setup several bikes with this combination >15 without issue including a RD9070, and while its true that the e tube project software does give a warning that the combination will not work properly it work. the reason for the warning it that the FD will auto trim for a 10 speed setup, not 11, but this is a non issue as long as you don’t ride in a 53X28, or 39X11, as you shouldn’t do anyway. be sure you have the latest e tube software, try updating all the 10 speed stuff first, than the 11 speed RD separately. also before you plug in the RD see that the FD is shifting properly, than plugin the RD. you do not need to do any complete system update as long as each components FPGA has the latest firmware it will work.

  • Marc says:


    My 7970 RD has been diagnosed as faulty as opposed to any of the other parts. I’m toying with the idea if opening it up and taking a peek. Have you heard of anyone rectifying problems by doing this

  • Jonathan says:

    I’m in need of some help, yesterday went for a ride (off-road) and after 20km the DI2 (sc-s705 with alfine 8) just went completely dead ! I checked all its connections but they where all still connected good , last I check the battery it was on two bars(in this ride). but still when I arrived home I charged it “it took around 1hr to get fully charged” reconnected it , but still the system is completely dead . do you have any idea of what’s wrong ?
    I live in Malta and over here there is no one that can help ..

    • Richard Balshaw says:

      Sounds like you are in crash mode. Press the button on the junction box for 5 seconds.

      • Jonathan says:

        I didn’t see any buttons ! on the junction box that I have (sm-JC40) there is not, and on the dash sc-s705 I didn’t see any aswell !

        • Richard says:

          Sorry Jonathan. Your system is clearly different to the Di2 Ultegra 6700 system I have

          • Jonathan says:

            Thanks anyway Richard,

            is the anyone that can help me resolve this ?

          • Di2diy says:

            First double check the plugs on the levers, remove and reconnect use the plug tool and be sure you hear the click, same with all connectors. if that does not fix it you will need to get a SM-PCE1 for diagnostics. there have been some issues with the SM BMR1 and Alfine and you may need to get a newer SM BMR2, unless you are using the SM BTR2

          • Jonathan says:

            the problem is , there is no one in my country that has the diagnose tool ..
            the system I have has the following parts : sm-btr1 , sm-jc40, sc-s705, sw-s705 and mu-s705
            today we tied to see if we can have an idea of where the problem is coming from with only a multimeter .. and I think we found something, the current stopped in the junction box (sm-jc40) , actually last reading of current we had was in the wire from the battery to this junction box than from it onwards there is no current in any other unit !
            so I’m guessing its from it, does my statement/finding make sense ?

    • Di2diy says:

      Did you try plugging and unplugging the connectors with the tool and are you sure they are in all the way… you need to use the plug tool. Also what mount, SM BMR1or2. its marked under the mount lever. I would not be sticking VOM probes into those plugs, it’s very easy to short the system out, you would need some special probe tips. if you short it out trying to check voltage it will trigger the polyswitch in the battery mount, or fry the FPGA in one, or all of the components. Also you can buy a SM-PCE1 on line, you need one.

      • Jonathan says:

        ok, problem resolved 🙂
        it turned out to be a short in a wire. when this wire was being connected, the system shuts down everything
        , the wire must have been hit with something but I couldn’t find any marks on it , when tested with multimeter it showed that its shorted so we changed it and all ok now

  • Romain Lalieux says:

    Nice source of information you have put together here! very impressive and easy to understand.
    I am contacting you to see if you could help me with a problem.
    I just bought a cervelo P3 2014 equiped with Ultegra Di2. My main interest in Di2 is the dual shifting (from the aerobars and the handles). However Cervelo has chosen to go with hydraulic brakes which at this stage does not exist with DI2 brake levers.
    The store told me at first I would just need to add sprint or climbing shifters on the handels. I am about to pick up the bike tomorrow and they tell me now that the wires coming with those climbing shifters are too short to reach the junction box if I want to install them by the break levers (ideal placement in my mind).
    Are you aware of any wire that would allow me to extend the pre-mounted wire in order to reach the junction box? Beside getting rid of the Magura brakes as a whole and installing DI2 levers and new brakes, do you see any other option if I want to have my shifters near the brakes?
    Thanks for your help

    • Di2diy says:

      who ever told you you could use sprint buttons with a TT setup is a moron, they can only be used with ST9070 or ST6870 road levers no matter what the length. you only have three choices, 1) ditch the brakes as you say, 2) hack the setup per;, 3) decide that you do not need shifters on the brake levers because you should not use the brakes and shift st the same time… I would got with 1)

      • Romain says:

        Hello Di2diy, thanks for your answer, I actually found a store yesterday in Montreal which does the same hack as illustrated in the link you sent me. Considering the price of the shifters, I think they are asking a reasonable price for the overall hack and installation and I ll go with them but thanks for taking the time to answer my question.

      • HarryB says:

        Couldn’t you connect the sw-r600 climbing shifter to a sm-jc41 junction then whatever length of ew-sd50 etube wire that is required to reach the 5 port front junction (sm-ew90b) that is installed on the 2014 Cervelo P3 rather than having to hack the components if your not good at disassembling and soldering tiny components and wires (and voiding the warranty)? Basically using the sm-jc41 as a gender changer.

  • Joe says:

    Just got a new bike equipped with the new Shimano disc brakes and Ultegra Di2 w/11 speed cassette. So the shifting is great and it’s really cool to be able to just touch a button and change gears….. Wait for the BUT
    it’s LOUD in most gears and some are so loud it sounds like I’m dragging a toaster on a tether behind the bike. Arghhhhh. The LBS mechanic seems perplexed and possibly deaf as if to suggest my hearing is somehow manufacturing the noise or worse, it’s all in my mind. I hate drivetrain noise and I’m kinda PO’d that I dropped some serious cha-ching to have to argue with a bike mechanic. HELP

    • Di2diy says:

      Get your hands on an owners manual, and learn how to adjust it yourself, it’s really not that hard, no tools needed.

      • Joe Biudo says:

        I took the new “whip” back for its third visit to my LBS in the hope this time given enough time and not being pressured (i.e. I want my bike back immediately) the “wrench” would be able to reduce drivetrain noise to a gentle whir or at least something comparable to my non-Di2 set up on my older and much less costly whip. I think I’m going to take your advice and get an owner’s manual because the noise is still prevalent and annoying as hell. Any direction that could be given regarding how I identify the model number of my grouppo and then obtain an owner’s manual would be appreciated. Thank you.

  • Dkevdog says:

    Does anyone know if there are extension cables available? I am considering a custom setup on a recumbent trike, and need to extend the built in cables on the Dura Ace bar end shifters… hopefully without the use of the JC40 junction box. Even a simple two port plug would do the trick….

    And does anyone know if Shimano plans to ever develop a front Di2 Triple derailleur?

  • Mark says:

    Hey folks…Alternate internal battery options question: I have a mix of 9070 and 6070 with the internal battery mounted to the chainstay (temporarily) until i’m sue I won’t need to access it again. I tried fitting the battery into both the seatpost and seattube with no luck. I have an aero shaped tube/post and the battery is just a hair too wide. Does anyone know of an aftermarket battery that might be a little slimmer?


  • Yangdi2 says:

    Hey do I need to change to a 11 speed crank if I wanna change my current 10sp di2 system to an 11 SP

  • I’ve got a problem in the connection to the front derailleur. It doesn’t ‘click-in’ anymore. Neither with a new cable. It sometimes makes contact but does not stay in place. Is the host for the plug servicable? Yes I always used the connection tool but apparently you can not disconnect/connect illimited times. (I rode 21000kms with the system 6770)

    • Carlton Bale says:

      I don’t know of a way to service the electrical connection on the front derailer. Unfortunately, I think your best option is to buy a replacement.

    • Di2diy says:

      This sounds like a warranty issue. I have noticed that the connectors do start to lack the strong snap after a few hundred connections on my test junctions but never fail to stay connected. Get a hold of a Shimano rep and see if they will warranty the FD, I think they may as this is not a normal wear issue. BTW why would you need to disconnect the FD cable more than a dozen times?

  • Eric says:

    Thanks for the great article. Really helped me a lot when building my bike. I do have one question though, have you had any experience with adding a second 5/3 port junction box to act as an external charger/RD adjuster? Right now I have EVERYTHING stuffed inside the frame, and while I can take apart the stem and what not to access the 5 port, I was wondering if I had a second 5 port that i used with a 4 port splitter, unpluged my RD, then used the splittler to hook up the RD and the other 5 port junction to charge my battery/adjust the RD. Would the system still “work” with 2 A junctions plugged in like that?

    • Carlton Bale says:

      Eric, you might be able to temporarily put a second junction in for charging and adjustments, but I’m not positive. So disconnect the cable going to the rear derailleur, and install the junction and an additional jumper cable for the rear derailleur. You definitely wouldn’t want to run it that way, nor update firmware or settings this way.

      A better option would be to do what @di2diy suggested:
      if you have basic soldering skills you can hack the BCR2 to be used with any setup. Just buy any length EW-SD50 wire cut and splice it to the BCR2 than you can plug it into the shifter port, or buy a SM-JC40 junction B and another any length EW-SD50 wire… than you can just go through the RD by plugging the SM-JC40 to the RD wire and the extra EW-SD50 wire to the RD and plug the BCR2.

      • Eric says:

        I will give that a try. Thanks! One last questio, are you cutting off the stock end of the BCR2 and soldering on the di2 wire so it only has the di2 wire now, or are you soldering them together so you are left with both ends?

        • Carlton Bale says:

          Eric, it’s a 2-wire system, so there is no reason you couldn’t have both connectors. In fact, you could have the standard connector plus TWO (both ends) of the EW-SD50 cable, for 3 connectors total. So all you would need to connect it to the system would be a SM-JC40 junction B at the rear derailleur cable end, and then use the 2 new connectors as the jumper wire between the add-on Junction B and the rear derailleur.

          Just be sure you get the polarity of the wires correct. I’m not sure how to describe which internal wire is which, other than to test it one way and see if it works. If not, switch the wires, and test it again.

          • Eric says:

            On the BCR2 cable there is a shielded wire and a non shielded one. Any clue which one to solder to red and which one to black? I have heard that both may work and charge, but one way will harm the battery. Any thoughts?

          • Di2diy says:

            the clue is; the center wire is +

  • BS says:

    Hi Carlton. I have heard of people getting error messages up and no response when trying to fit an RD 6870 to a 6770 system. I am trying to do this without a laptop connector. Is the only hurdle making sure the system is running the latest software or are there any other things that could stop the RD from working? I am sure my bike has the latest software but the new RD doesn’t shift when plugged in.

    • Carlton Bale says:

      BS: Firmware is the only requirement. Something needs to be updated. You really need a PC and software to troubleshoot and/or update firmware.

      • BS says:

        Carlton I bought the PC interface, updated the firmware to the battery holder and then the other components and it all works perfectly. Thanks for your help.

  • Paul Tierney says:

    Hi Carlton, thanks for the great detail! I have one question on the SM-JC41 junction box. I’m planning on fitting the sprinter switches onto my tri bars as a tidier alternative to the bar end shifters but the cable is too short to reach the handlebar shifters. If I use the junction box SM-JC41 can I connect both switches to the same junction box and two SD50 cables out of the junction box to each handlebar shifter?

    Thanks for the help 🙂

    • Carlton Bale says:

      Paul, this is correct but if you join the climbing shifters at the junction box, but you’d only want 1 wire from the junction box to one standard handlebar shifters. You can’t do this with the SPRINT shifters; they use different connectors.

      • Di2diy says:

        the sprint shifters will only work on road shifters 9070/6870, not only because its a different plug, but because it must go through the shifter nodule, and sprinter plug in the road levers thats why the are keyed differently. the sprint shifter buttons do not have an FPGA like the other components do to identify them on the CANbus network… thats in the road shifter module. a little known fact is that on the 9070/6870 road shifters you can use/hack any momentary switch with a e tube cable plug, for example, I have made several sprint shifter/cateye hacks that uses 7970 sprint shifter buttons and cateye buttons so you can have a sprint and climbing buttons running through the shifter port(s) on any 9070/6870 road shifters. All my customers including myself prefer this setup over the Shimano bulky climber buttons (SW-R600)

        • Paul Tierney says:

          Hi guys, thanks for the info, I won’t pretend I understood all of it but I get the idea! I’m stuck with the 6770 anyway so it looks like the Sprint Shifters are not good to me and will have to go back. Just one last question… I have a friend of mine who is good with cables, he repaired an SD-50 cable that I managed to split and it still works 100%. Is the cable itself for the Sprint Shifter different to the SD-50 cable of could I get him to join an SD-50 and sprint shifter cable together and plug them into the spare port on the 6770? WIshful thinking I guessing…

          • Carlton Bale says:

            Paul, no, that will not work. The sprint and standard cables are different because they function differently. The sprint shifter will not work at all with your setup.

          • HarryB says:

            The problem with using the sprint shifters is not with the cable itself as it is only a 2 wire cable, but with the fact that the shifters themselves do not have electronic logic chip so that they must pass through the shifter/brake module. The ends are keyed differently to prevent connection to the wrong device/interface. The climber shifter (SW-R600) does have the electronics imbedded so it can be used and plugged into a junction box, but it only has a 265mm long cable, If you can extend the cable by cutting and splicing with an SD-50 cable then it should work. The advantage is that the R600 has 2 buttons (unlike the sprint shifter which only has 1) so that you can use 1 R600 for the rear derailleur and if you want a second on the other bar for the front derailleur. The drawback with the R600’s is, as Di2diy has pointed out, that it is somewhat bulkier.

          • Di2diy says:

            Sorry but that is not correct, the SM-R600 will only shift the rear derailleur, no matter where it is plugged in, this is true for all e tube systems. As I said you can splice any momentary switch with a e tube SD-50 cable plug and plug it into the (lower port only) of 9070/6870 road shifters, this will not work with 6770. With a 6770 setup you are limited to the using the R600 for the RD only or SW-R671 Remote TT Shifter front and rear. same goes for the 9070/6870, with the exception of hacking the sprinter port.

          • Carlton Bale says:

            Ha ha, good point. I didn’t even think about it being 2 identical R600 climbing shifters proposed. I was picturing L/R bar-end shifters. In this situation, it’s probably best to upgrade the levers or give up on front derailleur shifting from the aero bars.

        • clive says:

          An exhaustive thread 🙂 but to be sure I’ve read this right, if I’ve got 9070 shifers with the sprint shifter already installed can I purchase a momentary switch and connect to SD 50 cable plug and insert that into the spare port on the 9070 shifter to place on the top bar instead of the bulky SW-R600.

          • Di2diy says:

            it can only be plugged into the sprint shifter port, the lower port, NOT the middle or top, as that will short the battery module. Since you already have sprint shifters you can splice the switch directly to that plug, I use the Cateye buttons.

  • Paul Tierney says:

    Thanks guys, you’ve been a great help. Much clearer now and what I need.

  • Ross says:

    Does anyone know if internal Di2 battery is compatible with Thomson Elite (zero setback) 27.2mm seatpost?

  • Scott says:

    Hi Carlton, wouldnt mind your advice on DI2, I currently have a Scott foil 15 with ultegra DI2 and love it, I am now in the middle of collecting parts on the cheap to build a tri bike, my thoughts were to buy Dura ace or ultegra DI2, I have purchase a 2010 Dura ace SW7971 bar end shift levers for 10 speed and 2009 ST7971 electronic lever pair 10 speed.

    Im a bit concerned I will buy the wrong bits to build a system up, is there any chance you could list all the relevant pieces of kit I need to gather to get a full system to fit to my tri bike once built?

    Many Thanks Scott

    • Carlton Bale says:

      Scott, I think your best bet would be to look at a complete 7970 groupset and get the component requirements that way. I don’t have a handy list of everything for this older configuration.

  • Don says:

    You guys have been very helpful in explaining what di2 parts are compatible. It’s a shame that Shimano is not this helpful.

  • Fra says:

    Hi everybody. I installed E-Tube on my Win7 laptop, I connected my bike with Ultegra 6870 (internal battery) but the sw doesn’t recognize it! It always displays ‘Connect…’ followed by three links to techdocs.
    I’ve tried to disconnect levers, RD and FD but nothing…
    What can I do?

  • AndyH says:

    Hi, I have installed Ultegra 6800 11 speed Di2. The front mech trim has a delay when at the extremes. For example; when the chain is on the 34 inner to 28 rear and then I upshift to the 50 outer, the chain rubs the front mech and it corrects this by auto trimming but only after 30 – 45 seconds. This also happens when the chain is 50 outer and 11 rear and I drop to 34 inner. the front mech takes a bout 15 seconds to re-trim. Is this normal or is there something I need to do. Thanks

    • You need to “customize/adjust” the “trim” using a PCE1 or BCR2 and a PC

    • James Frew says:

      This is not ‘normal’. You should not run with this as it will grind your components to early death.

      Are the components new? I ask this because derailleurs ‘having a mind of their own’ can be a sign of a failing/faulty component.

      If the Di2 system has been set up correctly the auto-trim will never behave this way. You should be enjoying silky, smooth, perfect shifts every time. I assume you have a correct chain-line, i.e. your crankset has been installed correctly. Set up according to Shimano’s guides.

      Persevere, the problem will be cured.

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