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

Shimano Di2 Groupset

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.
    • R9120, R9170 – syncroshift enabled with firmware 3.2.0 or newer
    • 6870, 9070 – syncroshift enabled with firmware 3.2.1 or newer
    • 6770 – no syncroshift firmware update will be offered

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 because it does not have the charging port to charge the 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.)
  • See the Shimano E-tube compatibility chart version 3.4.3 for more details

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 slowtwitch.com

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 to 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: E-tube_Proj_V_2_5_2.zip 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 (note: ProgramData is a hidden directory, click here for details on how to view it.). 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 the 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 dealer’s 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 http://e-tubeproject.shimano.com/
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_SM-BCR2_overview

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.
shimano_SM-PCE1_overview

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.
Shimano_ST-6700_Brake_Shift_Dual_Control

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.)
Shimano_ST-9070_Brake_Shift_Dual_Control

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.
Shimano_ST-9071_with_wire

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.
shimano-st-6871-ultegra-di2

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.
shimano_ultegra_6870_st-6870

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.
Shimano_SW-R671_Bar_End_Shifter_Dual_Button

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.)
Shimano_SW-9071_Bar_End_Shifter_Single_Button

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.
Shimano_SW-R600-climbing-shifter

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.)
Shimano_SW-R610_Sprint_ShifterShimano_SW-R610_sprinter_shifter_mounted

Alfine SW-S705 Right Flat-Bar Shifter: Reported to work with other non-Alfine setups.
shimano_alfine_sw-s705

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 for synchronized shifting.
shimano_sw-r9160_shifter

SW-R9150 Climbing shifters (pair): These tiny climbing shifters are about as small as the sprint shifters, but can be directly connected to a junction box and do not have to be connected as slave buttons to a brake/shift lever special port. They come with plastic mounts to make it easier to attach to bars beneath bar tape. They are ideal for synchronized shifting, with one controlling the upshifts and the other downshifts. These shifters require the BT-DN110 Internal Battery for synchronized shifting.


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).
shimano_ultegra_6870_fd-6870

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).
shimano_ultegra_6870_rd-6870

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.
shimano-alfine-s705-di2-11-speed-internal-gear-32-hole-hub

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.
shimano_sm-eww01

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 cannot be used with the SM-EW67 Front A Junction.

shimano_ew-wu111_ant_ble_wireless_unit

shimano_ew-wu101_ant_ble_wireless_unit
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.
shimano_alfine_705_display_unit

MT800 Digital Display with Bluetooth: Primarily aimed at XT mountain bike applications, this display allows toggling between the 3 synchronized shift modes (where 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 therefore 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.
Shimano_SM-BTR1_external_battery

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.
Shimano_SM-BMR1_External_Battery_Mount

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.
Shimano_SM-BTR2_Internal_Battery

BT-DN110 Internal Battery: This battery is required for Bluetooth wireless units and road groupset Synchronized Shifting functionality.
shimano_bt-dn110_internal_battery

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.
Shimano_SM-EW67-A-E_A_Junction

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.)
Shimano_SM-EW90-B_JunctionShimano_SM-EW90-B_Junction_bottomShimano_SM-EW90-B_Junction_all

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.

Image source: http://www.matosvelo.fr/index.php?post/1912/le-groupe-shimano-dura-ace-r9100-officialise
Image source

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.
Shimano_SM-JC41_B_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.
Shimano_SM-JC40_external

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.)
shimano_tl-ew02_tool

Common Questions (via Shimano):

shimano_di2_faq1
shimano_di2_faq2
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.) Amazon.com 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. Amazon.com 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. Amazon.com link
  • EW-SD50 Wire 3 between the Front Junction A and the 4-port Rear Junction B connector. Amazon.com link
  • EW-SD50 Wire 4 between the Rear Junction B and the Front Derailleur. Amazon.com link
  • EW-SD50 Wire 5 between the Rear Junction B and the Battery. Amazon.com link
  • EW-SD50 Wire 6 between the Rear Junction B and the Rear Derailleur. Amazon.com 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. Amazon.com link
  • Grommets for any place where the wire goes into the frame through a drilled hole. Amazon.com 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.) Amazon.com 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. Amazon.com 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.) Amazon.com 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. Amazon.com 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.”

2020-07-24

2,485 Comments

  1. What does the third update add to the system?

  2. What a great site! I’m running Ultegra Di2 6770 in 10-speed, but with the SM-EW90-B (the 5-port box). Steep learning curve, as I’ve just started thinking of upgrades. Any help on these questions would be much appreciated:
    1. Will SM-BCR2 (the internal battery charger) enable me to program using E-tubes?
    2. What additional benefit is the SM-PCE1?
    3. I’m thinking of “upgrading” Ultegra FD-6770 to DA FD-9070. Is there any benefit / difference?
    4. Can I run the FD-9070 with RD-6770? (I’m likely to upgrade to RD-9070 eventually)
    5. Will the SW-R600 (climbing shifter) work with that system (both 10 and 11 speed)?
    6. I had trouble with the (external) battery discharging quickly when I upgraded from SM-EW67AE to SM-EW90-B. Is that a known problem? My LBS upgraded the firmware (presumably with the SM-PCE1) and it seems to have been cured, but are there any lingering issues known?
    Many thanks in advance for any light on these.
    Bruce.

    1. 1. Will SM-BCR2 (the internal battery charger) enable me to program using E-tubes?

      Yes, if you have front junction SM EW90 A or B. This is how I programmed my 6770.

      1. Thanks Andy. I’ve found most of the other answers out by “suck it and see”:

        2. Still don’t know. Presently can’t see any need for SM-PCE1 over the SM-BCR2.
        3. Ultegra FD-6870 is smoother and quieter than FD-6770. DA FD-9070 is not discernably different to Ultegra FD-6870, except twice the price. Same speed, same smoothness, same noise level.
        4. Tried Ultegra RD-6870. Cannot imagine how DA version could be “better”.
        5. SW-R600 works fine in the system.
        6. Upgrade to the firmware seems to be the solution.

        In short, everything which runs e-tubes is inter-compatible. Unless you “need” Dura Ace written on your kit, Ultegra is as good as it gets. Save the money. Save weight by trimming your fingernails before riding.

    2. the SM-BCR2 can not do diagnostics and the SM-PCE1 can, so if there is something wrong with one of the components or the firmware did not update correctly you can’t know what’s wrong

  3. I assume the ST-6770 (10speed) only comes in the Road Bike-looking lever/brake rather than the look of the ST-6871 (more the TT lever/brake look)? Thanks!

    1. Chris yes, the only Ultegra 10 Speed shifter is the standard brake shifter- however because all of the Di2 components are interchangeable, I would assume that one could use the 6871 TT shifters provided the firmware is updated and the same.

  4. The green light on my junction box doesn’t light up when depressing the shifters, even after a full charge. Problem? I guess that as long as the red light works when it gets low thats really what is important, no?

    1. Author

      I can’t say I’ve ever noticed the green light being on or not except when charging, so I don’t consider it to be all that critical. The only concern is if there is another issue with a component or connection that is causing the issue.

    2. Yes there is a problem, thats the only way to check the battery level, something is wrong with junction box A. the RED light will not indicate battery level if the battery light is not working. Can you get it to go into RD adjust or reset mode?

  5. Great site, thanks so much for posting this. I have a 6770 10 spd and am about to order RD-6870 as well as an 11 spd chain/cassette for an upgrade to 11 spd. Can anyone confirm for sure that this is all that is needed for the upgrade. I.e.that I do not need FD-6870 and a 6800 crankset (my wheels are 10/11 spd already). There is some conflicting info on other websites that suggest that FD-6870 is needed as well and FD-6770 simply does not work when paired with RD-6870,

    1. Is there no one that has actually done the 10->11 speed upgrade and can confirm what is needed?

  6. Bjarni- I converted my Lightspeed Ci2 to the 11 speed last month. I also have a Lynskey R-255 that I built up in November that is completely 6870 including cranks, brifters and derailleurs. Yes, all you should need is the RD-6870, the CN-6800 chain, and your choice of cassette. Depending on firmware arrangements, you might possibly need to update firmware in components so they are all on the same page, but I have been using that setup for a few weeks without any real problems in shifting performance. I did not upgrade the cranks, which are FSA and while it shifts fine, it is noisier than my Lynskey which is totally setup as Shimano reccomends. The complete package does shift slightly better, but the overall the shifting is amazingly smooth on both. Th FD-6870 does shift slightly different than the FD-6770- but would be difficult to describe. It seem to push the chain all the way on to the upper or lower ring right to the limit stops, and then trims back off. I don’t notice this with the 6770, but I don’t know how that would effect shifting performance as it really doesn’t seem to make any difference.

    1. Thanks a lot for the response. My order is placed for the upgrade 🙂

  7. THANK YOU SOOOO MUCH!!! NOW I HAVE A FULL INFO !!! I’m trying to use my 6770 on my new BMC frame and like to have RD6870 to get 11 speed. Supper!!!


  9. Hello,
    I just started my Di2 carrer with an Ultegra 6770 set. I would like to use the Shimano Flight Deck Computer but I didn’t found any information if this set (with the ST-6770 levers) will work with it and if yes which cable set I need to connect the flight deck to the system. Can anybody help me with this problem?
    Many Thanks!

    1. Author

      Shimano hasn’t been clear on FlightDeck support of Di2. It was announced, then retracted, then perhaps released but with no details. As I understand it, you would need the 5-port front A-junction and it would wirelessly connect to the FlightDeck cycling computer to provide the current gear selection information.

  10. Hello,
    Today I installed a RD6870 on my bike. The rest of the system is the “old” 6770 type. Now I can’t get the RD to work, it doesn’t move. The front mech still works as it should. Do I need to upgrade the firmware on my old system to get it to “talk” to the new rear mech or what could be wrong?

    1. Author

      You definitely need to upgrade all of the component firmware versions. The Shimano software will also help with diagnostics.

    2. I too replaced the older RD6770 with the newer RD6870 on my bike and it does work fine. Yes, I did get the firmware on the 6770 upgraded first, so you will probably need to do the same.

      While the rear shifting works a treat and so does the front, I do get a little noisier drive train at the front on certain gearing. Am wondering if I need to upgrade the older 6700 chainset/crank at the front with a 6800 model to get a quieter drivetrain like previously. Other than the slight noise, it all seems to work fine and am happy with it.

      1. Does your front derailleur trim appropriately with the RD-6870?

        1. Yes it appears to be trimming well like before. Now that I’ve done a few hundred km after the upgrade, the front drive train seems quieter too. I’m guessing the new 11 speed chains needed to bed in with the front chain rings a little. I can’t say the new 11 speed made me any faster :-).. but I’m still very happy with it as I didn’t need to spend a lot for the upgrade.

          1. The FD 6770 will autotrim, but its autotriming for a 10 speed setup, thats why there is some noise with some combinations, its a useable combo, just not optimal.

  11. This is a great guide – thanks. Shimano should give you a job!

  12. Carlton…I just had my new ride built up with 6770/9070 di2, however I have an issue with the internal battery. It will not fit in the seat post or seat tube so I’d like to install it in the downtube. This can be done but removal is not easy and my mechanic said that the PC adaptor has to be connected directly to the battery for programming. I would think that all this could be accomplished through the 5-port junction box under the stem if I unplug all other devices. Am I wrong? Thanks

    1. Author

      Mark, you are correct. The external battery has to be plugged directly into the PC diagnostic tool to be updated. The internal battery does not; it can be updated as you described using the 3 or 5 port junction and the combo charger/PC tool. That’s how I updated my internal battery.

      1. This is true, however, when I updated my internal battery firmware, I was warned to disconnect the other components to avoid the possibility of the firmware update getting misapplied to the wrong component. This just meant temporarily unplugging the shifters from the upper junction block and unplugging the e-tubes at front and rear derailleurs, applying the firmware update (through the upper junction block, as normal), then plugging the components back in. Have your e-tube tool at the ready.

  13. Great blog! I’m getting a Di2 on my new bike (on order) out of curiosity how often have you been required to update the firmware?

    1. Author

      In my experience, there have been firmware updates available about every 4 months. However, I don’t think any of them are mandatory, so you don’t *have to* update it at all.

  14. Hi all – quick question ….with a new 6870 build with internal seat post battery and 3 port Junction A …..how many  EW-SD50 wires will i need ? or do you just buy a long length and ‘cut as needed’ ? im just not sure what wires/cables come with the junctions / chargers / battery etc ?

    Cheers
    Paul

    1. Hi Paul- with a 6870 build you will need 6- if using the three port junction. Personally i would opt for the 5 port, it is only a few dollars more and gives you additional shifting options should you ever choose to add some TT bars or thumb shifting. Either way, you will need one cable each for the brifters to the junction box, one cable from junction A to the rear 4 port junction, one to the battery, and then one to each derailleur. They come in various lengths, make sure to give yourself some slack when measuring. They can not be cut as they have proprietary ends on the cables.
      Arts Cycle gives a pretty good description and diagram, just remember that it shows the 6770 brifters which had a short cable already built in. The 6870 brifters do not have a cable attached hence the reason you’ll need to get two.

      http://blog.artscyclery.com/ask-a-mechanic/ask-a-mechanic-di2-wiring-and-another-bottom-bracket-question/

      1. Thanks mate – thats great ! …the Arts Cyclery diagram illustrates EW-ED50 cables ….can i safely assume EW-SD50’s are the same thing ….just get 6 in the correct lengths ?

        cheers again!

        Paul

      2. Also ….what would typical lengths be for a ‘standard’ 54cm TT road bike …Drop bars ….non TT etc ….for each –

        1 x Left shifter to junction A
        1 x Right shifter to junction A
        1 x Junction A to Junction B @ BB
        1 x Battery up seatpost
        1 x Rear D
        1 x Front D

        Cheers again!!

  15. Handy stuff here. Does anyone know if the SM-BCR2 USB Charger will charge an external battery SM-BTR1 so not needing old style SM-BCR1 charger? Not sure I can find anything definitive…

  16. If anyone is interested in upgrading a 6770 setup to a seatpost battery but want to use the This SM-EW67A front harness and not pay all that extra money for new shifter wires and 3or5 port EW90A junction box + charger, you can buy a seatpost battery kit on eBay including a charger that will allow you to charge through the harness via, shifter port. http://www.ebay.com/itm/301014528309?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649.
    You can also buy one for a 7970 setup including an EW7975 internal harness, or just the battery cable to plug into the EW7975 harness. You can also contact me direct via email [email protected]

  17. Hi all, another quick Q for u pls, thanks in advance ….

    DA9000 Crank, chainrings, chain and cassette….be ok with 6870 FD & RD ? ( will also be running 6870 shifters ) ….?

    Thanks again!

    Paul

  18. CHAINRINGS??

    If not using Shimano crankset, which chainrings are folks using for the 11-speed setup? Having any problems?

    Thanks all.

  19. Author

    Mark / Paul: The biggest concern with front chain rings and Di2 is the rigidity. You want the larger front ring to be as strong as possible to resist flexing against the higher forces of the front derailleur. Having said that, any front chain ring should work, just a with perhaps a little more hesitation. If you’re using non-Shimano cranks/rings, I suggest PraxisWorks; they are forged for additional strength and have very good shift ramps.

    1. Hi Carlton ….thanks again ….i was more just looking for confirmation of my current set-up …

      with the following existing set up:

      DA9000 Crank,
      DA9000 Chainrings,50/34
      DA9000 Chain
      DA9000 cassette 11/28

      Will it be ok to use an Ultegra 6870 FD & RD ….( will also be running 6870 shifters ) ….?

      Thanks again!

        1. Music to my ears …thanks again Carlton ….and can i assume this setup will work at least as good as it does with the full 6800 drive train ? (albeit lighter) ….but functionally …as good ….

          Cheers again!!!! Much appreciated

    2. Carlton…I ended up using Specialties TA chainrings and am having trouble going from the 36 to the 50. It doesn’t want to lift it at all. After buying these (super light) rings I realized that they were 10-speed. And in hindsight, I’m not sure they are not Campy.

  20. First, thank you for such a good review and description of all the components!

    1) I was wondering if it is possible to configure the Dura Ace rear derailleur (RD-9770) to work with a 10 speed cassette. Some places, I read yes and others say no.

    2) What type of programming is done when connecting a PC ? Is the software easily available ?

    3) I am thinking of using the internal battery SM-BTR2 in my 2011 Trek Madone 6.9 SSL. Trek says it is fine. I am curious, does the SM-JC41 get installed Inside the frame through the bottom bracket hole ?

    Thanks

    1. No, RD 9070 is 11 speed only, there is no firmware hack or e tube option to make it 10 speed. However you could use the limit screw to lock out the 11th cog, the spacing between 10 and 11 speed is vary close to the same, it will shift ok but not perfect in all positions

  21. Can I replace a B junction box (SM-JC40) with an A junction box (SM-EW90-A) while leaving my existing A junction box (SM-EW67-A-E) at the bars. To enable the use of the internal battery? I want to keep the SM-EW67-A-E up front because it is smaller and fits perfectly inside my stem.
    Thanks

    1. No, you can only have one A box, besides if you put the EW90 in the frame how will you charge the battery, it charges through the EW90. However there is a kit on eBay that you can install and keep the EW67, it plugs into the JC40 after removing the current battery it comes with a charger that will allow you to charge the seat post battery through the open port of the shift lever, or the RD cable with a JC40 box, look for Di2 SEAT POST BATTERY KIT FOR ULTEGRA 6770,6870 or Dura Ace 9070, FITS 27.2.

  22. 1) What type of programming is done when connecting a PC ? Is the software easily available ?

    2) I am thinking of using the internal battery SM-BTR2 in my 2011 Trek Madone 6.9 SSL. Trek says it is fine. I am curious, does the SM-JC41 get installed Inside the frame through the bottom bracket hole ?

    1. (Pierre, this information in already posted here above)
      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.
      shimano_SM-PCE1_overview

      Shimano E-tube Project Windows PC Software: This free software is used to update the firmware of all components. It also can be 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, where the shifter is held and the rear derailleur shifts through multiple gears until the shifter is released. The speed of the gear changes during multi-shifting can also be configured. The software is available from http://e-tubeproject.shimano.com/.

      I have found its much easier to pull the crank on the trek to do the internal install, puttin the JC41 through the hole for the battery mount is doable but routing all the wires and connecting it all is tough, just pull the crank and save yourself from the hassle.

      1. Thank you for the detailed answer and sorry I didn’t notice the détails on the programming above. I’ve exchanged multiple e-mails with Trek because they keep on only answering the first question of a multi-question (numbered!) e-mail… Just been a bit of a frustrating day… 🙂

        You confirmed that I should simply pull the crank and run all the wires and junction box the easy way. Thanks !!!

  23. Thanks for the great review. When I called Shimano today to discuss 11 Speed upgrade of my Ultegra 10 Speed Di2 they claimed that I would need to replace my front derailleur in addition to my rear derailleur as the “brain” for the system is now located inside each of the individual derailleurs, has that been your experience or are they just trying to upsell me?

    1. The 6770 FD will work with the 9070, 6870 11 speed RD but it will be auto trimming for a 10 speed setup. Depends on the chainring and cassette combo on how much of a difference it will make, but as long as you don’t ride with max cross over i.e 39×11 or 53×28 it will be fine.

      1. I was planning on 50-34 compact crankset with 32-11 cassette for maximum flexibility during RAAM

        1. Well like I said just don’t run a bad chain line and you will probely not notice any difference.

  24. Hi Carlton,
    Thanks for sharing this info.
    I have one query though…
    I want to set my Time Trial bike up with Di2 and was wondering if the following is possible.
    Can I link up the rear Ultegra 6770 and front Ultegra 6770 mechs with a 3 port SW-EW90 connected to SW-R671 shifters only?
    I dont want the expense of buying ST-6871 levers so hoped the TT shifters would do what’s needed on their own. I assume the ‘brain’ of the shifting is in the SM-EW90 junction box?

    Any advice/ help will be greatly appreciated.

    Thanks again

    Alan Hall

  25. If you were going to buy a bike and you had two choices. One being Dura-Ace Di2 and one being Ultegra Di2 and there was $1000 difference what would you buy. It is for a TRI bike both being 11 speed

    1. Is everything else on the bike identical? I would probably base my decision on more than just groupset but for $1000 saving I would personally go Ultegra every time.

    2. Author

      I agree, would definitely go Ultegra. The $/gram cost is pretty high, and the performance and weight differences are very low.

      1. Everything is basically the same. All the brake system is Ultegra or Dura-Ace depending on bike. The handle bars are Oval 950 on Ultegra bike and Oval 960 on Dura-ace

  26. Hi,
    after a crash, my Dura-ace Di2 system got blocked. The battery has charge, and when I use the button bellow the 3-port junction, the derailleur works, but the problem is that none of the shifters work. There seams to be a disconnection between the shifters and the 3-port junction. Any advice on that problem?
    Thanks in advance

    1. Author

      Using the PC Diagnostic tool would be my first suggestion. If you don’t have that, disconnect all shifters and then connect each one at a time to see if you can isolate the problem or find an isolated problem.

      1. Thanks a lot Carlton, I hope i can find a PC Diagnostic tool in Ecuador !!! I really doubt it. Anyway, thanks for your great community help trough this page!

  27. Would it be possible to take the switches and connectors out of ultegra 6770 levers and put them in dura ace 7970 levers. I actually prefer the look of the 7970 levers to 9070. That way I get E tube wires into 7970 levers, Bingo!

    1. Author

      Gav, it wouldn’t be a direct swap of parts. The electronics and levers are shaped differently between the two. I wouldn’t recommend it as it would be a huge amount of work with lots of customization. But I guess with enough time, effort, machining, and electronics skills, anything is possible.

  28. Great site! sharing with all my cycling buddies. Question: Can the external SM-BTR1 battery be left on the SM-BMR1 External Battery Mount and still be charged with the SM-BCR2 connected to the EW90-AB?

    1. I just need confirmation this has been tested to work or not work. but according to Competitive Cyclist it does.

      Quoted from Competitive Cyclist:

      The charger is made to accommodate both internal or external battery systems by connecting to the SM-EW90 junction box.

      1. Author

        I can’t say for certain, but it was my understanding that the external battery could not be charged this way as it did not have the necessary charge-limiting circuitry inside.

  29. Hi Carlton,

    Great info source – congratulations – and well done on sharing it with everyone. Can I ask a short and (apologies in advance) possibly stupid question. Can you use 6870 electronic shifters with 6800 mechanical derailleurs? I have a mechanical group and was looking to maybe purchase electronic shifters to replace a shifter with cosmetic damage with a view to upgrading to Di2 in stages.

    Can you let me know if known or perhaps direct me to a source that can confirm either way please?

    Thanks in advance.
    Dave

    1. Not possible! Except for the brakes, but no shifting.

  30. For the pce1, did you have to download other software besides the etube software to get it to work? I plugged my pce1 after downloading etube and it does nothing.

    1. Hi, a secondhand frame I’ve bought comes with old dura ace wiring including battery and external mount. I’m moving to new di2. I can keep the battery but what about the mount? I think not as the 4 wire cable is an integral part of the mount. Can some one confirm? Thanks Dave

      1. It can not be used with e tube system.

    2. Author

      Mike, yes, all you need is the SM-PCE1 and the free etube software from Shimano. Make sure the USB device driver initializes properly in windows and make sure there is battery power to the components you’re upgrading.

  31. I just got the parts to upgrade from 10 speed Ultegra Di2 to 11 speed, will be replacing crankset (with DurAce), chain, and 11 speed medium cage Ultegra RD to accept Ultegra 11/32 cassette. When I swap 10 speed RD with 11 speed, is it “Plug & Play” or do I need to do some sort of firmware or programming update?

    Thanks

    1. Author

      Gary, it’s hard to say if you need to do anything or not because it depends on which version of firmware your existing components have. If it works and you’re happy with it, no upgrade required. But for the highest level of compatibility/reliability, I’d recommend making sure everything has the latest firmware version.

  32. Carlton,

    My DA9070 set up is playing up, shifting started to be hesitant (shifting would happen 1 sec after pressing the shifter) and now its not working at all unless I keep my finger pressed on the shifter for 30+ secs!! (with full batt)

    In addition to this the green ‘charged’ light comes on of its own accord every now and then.

    I have the E tube software package and the SM-BCR2 connector but it will not allow me to make a connection, it charges but will not connect to e tube.

    Pulled all the cables & reconnected, reckon it must be a bug. You heard of anything like this before?

  33. My LBS was upgrading my Ultegra 10 Di2 to 11 speed. I’m keeping the existing FD and swapped the crankset for a DurAce 11 speed. The FD works fine but the RD does not seem to respond in anyway to the shift key on the brifter. The green light comes on when you hold down the button but it does not seem to send any info to the RD. They double checked all electrical connections but it sill does not work, any suggestions?

    1. Thanks Carlton, I had LBS with programmer update firmware and she seems to shift perfectly. If you recall, I only swapped the RD for 11 speed and left the FD alone yet it seems fine. I will take out on a long ride with some steep climbs tomorrow to see how it works in the real world.

  35. Thanks you so much for putting this together. Your site is awesome. I was hoping you might help me with an issue please. I just installed a 6870 RD on my 6770 bike. The derailleur won’t work at all. I’ve tried re-connecting the cable several times to no avail. I then connect my old 6770 RD and it works fine. Any ideas would be appreciated. Thanks!

    1. Have you updated the firmware???, if not it will not work.

  36. Hi Carlton, wow that’s comprehensive I just wondered whether you had any idea about the possibility of using the Hydraulic DI2 levers with the Alfine rear hub gear? It seems bonkers that it isn’t a stock option although I’m sure it will be very quickly.

    1. Author

      As far as I know, the Alfine BL-S705 levers send the same command signals as the R785 hydraulic shift/brake levers, so they should be able to be used together, but I haven’t seen it myself so I’m not 100% positive.

      I agree, that combo has to be coming very soon from Shimano.

  37. Ah right great I thought I hadn’t imagined that from what you’d written I feel slightly less silly. Thanks again, time to get out the credit card ;0)

  38. gents….all this information is doing my head in. i am a user of the 7970 DI2. bought it second hand not long ago. it worked just as advertised until just recently the RD has been shifting without provocation. all rides have been in the dry. have run through the set up on numerous occasions only to get the ghost shifting come back. the LBS isn’t that local. what would the next step be that I should be looking into….is the diagnostic tool going to help with this
    cheers

    1. Author

      Marc, my guess is that that the tool will not help. The design of the original Di2 system is much more prone to shorts (to ground/with other wire) causing a shift. You most likely need a new harness. I’m assuming that it is always an upshift or a downshift, not both. That would tell you which wire to isolate.

      There is also the possibility that it is a mechanical problem, and not electrical at all. It could be that the internals of the rear derailleur have worn to the point that it is not holding position properly. In this case, a new rear derailleur (or possibly a new spring kit?) would be required.

    2. I would also suggest that the RD Servo is going bad, I have seen this several times, starts ghost shifting than will just stop shifting all together. However it also could be the rear harness. A couple of questions; is the wiring internal or external? if internal did you use the shrink sleeve on the connectors when you installed the harness? often times people who install a use harness (EW7975) do not use the proper shrink sleeve (adhesive lined) and just tape the connectors with electrical tape, than the connectors are not waterproof… you would be surprised just how much moisture is inside a carbon frame after just one ride in a light rain, or washing. Also sometimes using a used EW7975 harness can be an issue, depending on how much care was exercised when it was removed. I do custom retrofits on non Di2 specific frames and build custom seatpost harness kits for both e tube & 7970. I have found the 7975 harness to be quite hardy, but they can be damaged if uninstalled by gorilla bike mechanics. If you can get another harness like an external, and install it temporarily to see if it still acts up, it will answer the question of bad RD or harness. I have several external harnesses, and could work something out if you are willing to pay shipping cost. contact me at Di2diy at gmail.com

  39. I would also suggest that the RD Servo is going bad, I have seen this several times, starts ghost shifting than will just stop shifting all together. However it also could be the rear harness. A couple of questions; is the wiring internal or external? if internal did you use the shrink sleeve on the connectors when you installed the harness? often times people who install a use harness (EW7975) do not use the proper shrink sleeve (adhesive lined) and just tape the connectors with electrical tape, than the connectors are not waterproof… you would be surprised just how much moisture is inside a carbon frame after just one ride in a light rain, or washing. Also sometimes using a used EW7975 harness can be an issue, depending on how much care was exercised when it was removed. I do custom retrofits on non Di2 specific frames and build custom seatpost harness kits for both e tube & 7970. I have found the 7975 harness to be quite hardy, but they can be damaged if uninstalled by gorilla bike mechanics. If you can get another harness like an external, and install it temporarily to see if it still acts up, it will answer the question of bad RD or harness. I have several external harnesses, and could work something out if you are willing to pay shipping cost. contact me at Di2diy at gmail.com

  40. Wondering if anyone could help with a problem trying to update the Di2 firmware using E-Tube Project ver 2.5.0 . When I click on “Connection check”, it tells me that the following units are connected:
    SM-EW90-A
    ST-9070-L
    FD-9070
    ST-9070-R
    RD-9070
    and that a firmware update is available for SM-BTR2. But after clicking “Next”, it just keeps going around in circles, going back to “Unit recognition”.

    In the main menu, the buttons for “Customize”, “Error Check” and Update firmware” remain grayed out. Still available are: “Connection check”, “Preset” and “Change bike type”.

    Thanks for any help.

    1. Try disconnecting everything but the battery and update just that one component. If that doesn’t work, try connecting directly from the A junction to the battery with no extra junctions/connectors/wires in between.

      1. Thanks for the info. I also have this going in parallel with my LBS, which is trying to contact Shimano for an answer. I can suggest your solution to them.

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