I 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:
- Di2 General Overview
- Compatibility: Between 6770 10-speed, 6780 11-speed, 9070 11-speed, first-gen 7970
- How to Check Battery Level
- How to Adjust Rear Derailleur Trim
- How to Adjust Front Derailleur Trim
- Dealer Installation Manuals
- Shimano E-tube Project Software – Change Settings and Update Firmware
- Chargers, PC USB Interfaces/Programmers
- Component Overviews
- Shift/Brake Levers
- Dedicated Shift Buttons
- Front Derailleurs
- Rear Derailleurs
- Display Units and ANT Bluetooth Wireless Communication Modules
- Batteries and Battery Mounts (Internal and External)
- Front Cable Connection A Junctions (with charger ports and LED status lights)
- Rear Cable Connect B Junctions
- Cables, Grommets, Cable Install Tools
- List of Components Needed to Build Your Own Di2 System
- Technical Details of the Di2 CANBUS protocol and signaling
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:
- Extremely low shifting effort, which generally results in more frequent shifts and therefore better gear ratio selection.
- Greatly improved shift quality, especially for the front derailleur chainrings, allowing shifting under full power with almost no chance of a dropped chain.
- 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.
- 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.
- 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.)
- 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.
- 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
Historic 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.
- 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.
- 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.
- 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.
- Next, operate shifting switch 4 times to move the guide pulley toward the outside by 4 steps to the target position.
- 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.
- 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.
- 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 Ultegra 6770 Dealer’s Manual: http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Ultegra/UltegraDi2/6770Di2_DM_EN_v1_m56577569830773882.pdf
- Shimano Ultegra 6870 Dealer’s Manual: http://si.shimano.com/php/download.php?file=pdf/dm/DM-UL0001-00-ENG.pdf
- Shimano Dura-Ace 9070 Dealer’s Manual: http://si.shimano.com/pdf/dm/DM-DA0001-00-ENG.pdf
- Shimano Alfine Di2: http://si.shimano.com/php/download.php?file=pdf/dm/DM-AL0001-03-ENG.pdf
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.
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.
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 for synchronized shifting.
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).
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 cannot be used with the SM-EW67 Front A Junction.
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 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.
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.
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.
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.) 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.”
great write up many thanks
Thanks, I’m glad you found it useful.
Carlton, great write up. I had the UDi2 installed in my Look 695. Simply awesome. It is so smooth I have to look down at my cassette to make sure it has shifted!! I have an annoying rattle that I think is the battery holder mount. Since it mounts under the water bottle cage I think the road vibration is causing the noise when the battery moves against the frame and vibrates. Any thoughts on a correction for this? Thank you.
I’m not sure what to do for a long term fix other than tape to build up the pressure fit. To isolate the source of the noise, try using wrapping with rubber bands.
Thank you Carlton. Funny you mention that. I was playing with the idea yesterday attempting to make sure that was where the rattle was coming from. According to the Shimano website there are spacers that were to be part of the battery holder. It does not look like they were used. That may be one more option. Thanks again and ride often and ride safe!!
Just trying to build a 9070 di2 bike with a 10 speed 6770 rd ( needs to be 10 speed for various reasons) and although it should work according to yourselves and the chaps at calfee, we can’t get the shifters to work the front or rear much. Any ideas?
If neither shifter is controlling either of the derailleurs, I don’t think the problem is related to Ultegra/Dura-Ace compatibility. First of all, what troubleshooting have you tried? Here’s what I would suggest:
1) Make sure you have power; the battery can be difficult to get the connector seated properly. Check that the LED on the Front A Junction comes on when you press / press-and-hold the button.
2) Connect it to a the PC interface (Shimano e-tube software). Do all of the components show up? Do you have the latest firmware in all components?
3) Disconnect the front derailleur. Can you now shift the rear derailleur?
4) Disconnect the rear derailleur. Can you now shift the front derailleur?
5) Are you sure your front A junction is working properly? Are you using a SM-EW90 front junction?
Let me know what you find.
Can the “SM-EW90-B Dura-Ace 5-Port Junction:’ replace the “SM-EW67-A-E Ultegra 3-Cable Junction” (1st pic above) I’m looking to make the use of the ‘SW-R671 Dura-Ace 2-Button Time Trial/Triathlon Bar End Shifters” easier if I need to remove the TT bars than unwrapping the bar tape and disconnecting from the 2nd port in the “ST-6770 Ultegra Road Dual Control Brake Levers/Shifters”.
Thanks
Mike, yes, the “SM-EW90-B Dura-Ace 5-Port Junction” can replace the “SM-EW67-A-E Ultegra 3-Cable Junction”. (Don’t you love Shimano product names!) I’m pretty sure that you will have to get two additional cables to connect the “ST-6770 Ultegra Road Dual Control Brake Levers/Shifters” to the 5-port junction. The time trial shifters come with cables permanently attached and will plug directly into the 5 port junction.
Thanks for the quick reply, I’ll give it a try and post my results.
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!
Hi, just want to clarify a compatability point. If I use DA 9070 shifters with an otherwise Ultegra 6770 Di2 setup, will I be able to hook up the SW-R610 Dura-Ace Sprint Shifter. Cheers Wal
Wal, yes that setup should work fine, though I have not personally tested. The wiring connector is what is unique about the sprint shifter; the shift signal it sends is the same as all the other shifters.
Will the new ultegra 6870 Di2 11 speed derailleurs be compatible with ultegra 6770 STI levers.
Jos, although I haven’t tested it, I’m positive that the 11-speed Ultegra rear derailleur is compatible with all of the existing Ultegra and Dura-Ace shifters. They all send identical upshift/downshift commands.
Thanks Carlton, I think I am gonna give it a try.
Dear Carlton,
I want to try and rebuild an ultegra di2 10 speed for mountainbike use.
Can I use the sw 600 shifters and plug themdirectly into the junction sm 67a ?
Or do I need to have an additional junction, like the sm jc 41?
Thanks for the reply and the usefull info…
Dries.
Dires, you are correct that the sw-r600 shifters have the male cables ends, as does the SM-EW67-A-E Front “A” Junction. You will need to use a SM-JC41 Internal “B” Junction to connect the 2 together. Or use a SM-EW90 Front “A” junction instead.
For mountain bike use, I’ve read of people doing modifications to install long cages on the standard road rear derailleurs (for better mountain bike gear ration compatibility.)
I hope this helps!
Thanks very much for the very fast reply!
Many greetings from Belgium and keep up your great posts…
Hi
Can I plug the R671 TT aero shifters (to put on the end of clip-on aero bars) into the port on the 6770 road bike STI levers?
Thanks
Daniel
Yes, you should be able to. All shifters use the same cable connector except for the sprint shifters.
Fantastic write up. I have a 6770 that is internally wired but with an external battery mounted to the seat post. I would like to convert that into an internal battery. From your write up it looks like I need the SM-BCR2, SM-BTR2 and SM-EW90A. I currently only see the SM-EW67A which I assume is replaced by the SM-EW90A. Lastly every where I have looked says that you need to install new firmware updates to use the new internal battery. I cringe when updating firmware on anything, how safe is all this? I would hate to screw up a perfectly working system just to get the battery off my seat post. Thanks, Tom
Tom, you are correct on the replacement parts required to convert to an internal battery mount. I’ve installed several firmware updates and never had any issues. It seems to be a robust process.
Fantastic write-up!! This def is very useful… One question for you Carlton. I am installing the internal battery into my BMC TM01 (so not doing the external battery in the designated space in the frame). This was based on advice from BMC…. one question though… any thoughts on how to secure the internal battery in the seat post? I have another BMC and they installed it by wrapping insulation around the battery which works fine. Any thoughts on alternatives?
Thanks again for the write-up!!! Yoeri
Yoeri, I did exactly what you described: cut some pipe insulation, taped it around the internal battery, and installed it down in the seatpost tube in the frame. The snaprings that come with the battery require special mounting hardware that is more of a pain to fabricate than it’s worth. So unless you have a seatpost specifically designed for the Di2 battery and snapring, look for other options.
I originally had my battery installed in the seatpost itself, but that was a pain whenever I disassembled it (for travel, etc.) and had to disconnect the battery. So I moved it to the seatpost tube in the frame and found it to be much more convenient. I taped a string to the battery/insulation bundle to make it easy to pull-out if necessary.
Thanks a ton Carlton… interesting to learn you positioned the battery in the seat post tube IN the frame, not in the seat post itself… great approach and will most def copy this! Thanks for replying. I am already looking forward to the upcoming tri and bike season (as I am drinking my glass of vino…). Cheers, Yoeri
Carlton — fantastic writeup. Thanks a lot. This was all very useful background for confirming my shopping list prior to converting my Cervelo SLC-SL to Ultegra Di2 with an internal battery in the seat tube. Everything works great.
Now I’d like to do the same to my Cervelo P3C TT bike. The only question mark is what to do about shifter controls on the pursuit (base) bars. The ST-9071 brifters look great, but they’re hard to find, expensive, and I like my existing aero brake levers just fine.
It seems *theoretically* possible to plug *two* SW-R600s (positioned near my existing brake levers on the pursuit bars) and a set of SW-R671s (on the end of the aerobar extensions) into the SM-EW90-B (5-port) Junction A.
Will the system actually allow this, and will the E-Tube software recognize the two different SW-R600s independently and allow me to assign one to the FD and one to the RD? Or will the system insist on recognizing only one SW-R600 and allowing RD control only?
Michael, I debated the same and eventually ordered the ST-9071 brifters from http://www.alexscycle.com/ in Japan for a total cost of ¥37,933 ($390 USD). They were shipped via air mail and arrived in about 4 days with no additional import fees.
To answer your question, it’s my understanding that multiple shifters of the same kind can be installed and configured. You just plug them in one at a time to connect/configure with the PC software. (Disconnect PC software between swaps.) Once everything is configured separately, plug everything in and you’re good to go.
Great… thanks again… the new E-Tube system *should* allow this, so I’m off to try it.
I’ll report back with hard evidence one way or the other.
If there’s a gotcha, I can salvage one to use as a climbing shifter on my SLC-SL and sell the other one to finance the ST-9071s.
Hi Michael, I too have an SLC-SL and want to fit DA 9070 di2 with internal battery. Can you give me some info on how you went about this – any drilling of frame, any splicing of cables, how you routed cables etc. Would really appreciate any advice.
Regards
Graham
Hey Graham,
Here’s my recipe for the SLC-SL. The result looks great and has withstood six months of riding without a hitch.
I ran *most* of my wiring internally, with one exception — I used an external Junction B (SM-JC40) screwed into the old cable guide mounting nut under the bottom bracket. The resulting assembly sits mostly out of the wind (with the plugs positioned aft), and lets me easily unplug the FD, RD, internal battery or cockpit controls as needed to update firmware or perform tests. All four E-Tube wires use the original down tube shifter cable exit hole to enter the frame and head to their respective destinations on the bike:
a) RD — wire exits out the existing hole in the end of the chainstay.
b) FD — wire exits out the existing FD mechanical cable hole, and is held in place against the frame and away from the crankset with some Di2 external wiring tape.
c) Internal battery — wire enters bottom of seat tube by threading around the bottom bracket shell. I taped some foam to the battery to snug-up the fit in the seat tube and prevent rattling. Be sure to tie a string to the battery and tape the end to the inside of your seatpost in case you need to fetch it for replacement down the road. Also be sure you can insert the battery far enough to allow proper insertion of your seatpost. I have a 58cm frame so this was possible without cutting my seatpost.
d) Cockpit Junction A (I used an SM-EW90 5-port attached to the stem to give myself expandability options in the future) — wire exits through a custom 6mm hole I drilled about 5mm aft of the headset on the top surface of the top tube. This is the area that Cervelo recommends (probably because the carbon is thicker and reinforced here around the headset).
No splicing of the E-Tube wires should be needed. The top tube hole takes awhile to drill, so bring your patience and go slow. I drilled a small pilot hole first. Go easy with pressure at the end so you don’t damage the other side of your frame when you finally break through. I didn’t use a special bit, but it dulled considerably so I threw it in the trash when I was done.
I threaded the wires through the frame by passing shifter cables first and then taping the two together for guidance. Use the tape sparingly around the connectors since they’re barely small enough to get through the holes.
I used Shimano’s grommets to cover the exit holes and hold the wires in place for a clean OEM look. I used an SM-GM01 for the top tube hole but needed to custom-trim the waist of some GM02s with an exacto knife to get the right fit on the FD and RD holes.
Hope that helps!
Hi Michael, thank you so much for taking the time to reply, and in such detail. This is exactly the information I was looking for. I do have a couple of questions which I hope you don’t mind me asking:
1) are you able to use the ‘internal’ junction box for the 4 wires I.e does is fit back inside the frame via the original exit hole on underside of down tube?
2) does the mechanical exit hole for the FD cable need to be altered to take the di2 wire?
3) did you use shimano cable ties/zip ties that come with the di2 wires to prevent rattling inside the frame and if so, is it necessary to use them on ALL di2 wires?
4) I too have a 58cm frame and was wondering if you could advise on the best lengths of di2 wires to buy?
5) you mentioned using shimano tape to hold FD cable in place – is that easily obtainable?
6) I’m really pleased to hear you managed to use the internal battery as I was concerned that it may not fit. What did you use to wrap it to prevent rattling?
Thank you again for your help. It is much appreciated and I cannot wait to get started.
Best wishes
Graham
Hey Graham,
No worries on the extra questions — I’m sure the shoe would be on the other foot if you completed this project first!
The original shifter cable exit hole on the SLC-SL down tube is not large enough to fit an internal JC41 junction box without further modifications. Others online (including Cervelo) have described widening the hole with a dremel tool, but I didn’t bother as I wanted an external junction for convenience.
I didn’t alter my FD cable exit hole, but it was a tight fit to get the E-Tube wire connector through. I had to tug the connector with some needle nose pliers to encourage it.
I removed Shimano’s internal wire ties for routing simplicity and haven’t had a rattling problem.
I can’t remember the wire lengths I used, but I used a string to preview the lengths I would need and then added 25% to all the lengths for good measure. You don’t want to buy too short! And the overage will be hidden internally anyway.
Shimano’s “wire cover kit” for externally-wired Di2 setups is widely available through online stores and eBay. I just used one of the short covers and saved the rest as backups. Many rainy rides here in Portland over the winter haven’t dislodged the original.
I used some thin strips of rolled packing foam I had lying around to slightly widen the girth of the battery before inserting it (it doesn’t take much). Again, I used a string to pre-measure the depth I needed to achieve to stay clear of the bottom of the seatpost before re-insertion.
Finally, I just covered my unused down tube shifter cable entry ports with super-aero black electrical tape… 😉
Good luck!
Carlton, this is a great write up, a one stop encyclopedia of answers. I was wondering if you have heard anything with regard to the new ultegra 6870. Are we to assume since the new components will use the e-tube system they will again be cross compatible?
Also, sinc the rear der is the only device that knows or cares if it is 10 or 11 speed, it would theoretically be possible for the component to receive new firmware to allow for 11 speed on a 6770 deraileur. I have heard rumors of this from mechanics from my LBS who heard this at Interbike. Do you have any in site into this?
Dkevdog: Everything I’ve seen indicates that the 6870 system is completely cross-compatible with the 6770 and 9070. I would be shocked if Shimano offers a firmware upgrade to make the RD-6770 (10-speed rear derailleur) compatible with 11-speed. I think a RD-6870 will be required. I post an update here if I hear otherwise.
Hello Carlton,
Another question if I may…
Is it save to use an ultegra 10 speed group with an ultegra 11 speed front derailleur?
Will they work properly together?
And yet another question about my mtb-di2 project.
As I am using 2 sw-r600 shifters, I proberly have to assign the one that needs to control the front derailleur, and the one for the rear derailleur, but I need the pc1 interface for that.
Much to my surprise, I’ve noticed that the charger of the internal battery can also be used as an pc interface but is much cheaper.
Do you know which differance there is between the two
(except that one is capable of charging a battery) and which one I must buy?
Thanks for the help…
Yes, the 11-speed front derailleur will work fine with a 10-speed chain/gears/rear derailleur, though Shimano will officially say it’s designed to work best with the skinnier 11-speed chain size.
I recommend the internal battery, 3- or 5-port front Junction A, and the battery charger PC interface. It’s the default configuration going forward for Shimano groupsets. The battery charger PC interface is cheaper and does everything except advanced diagnostics (which would very rarely be required.)
Thanks again for the great help…
Greetings…
I’m just starting to get interested in Di2 ultegra 6870 but i’m getting concerned over what is needed. Do I need to purchase the connector pc kit? How much should i expect to drop on a full 6870 system?
Chris- I do know that you do NOT need the PC connector kit unless you plan on doing shop level diagnostics and testing of the components. I made the mistake and purchased the PC Connector thinking I needed to make feature upgrades and firmware changes to my 6770 system. Fortunately I stumbled upon Carlton’s blog here and realized my mistake and returned the PC connector kit and bought just the charger for the internal battery. I can confirm that is all that is needed to allow program changes and firmware upgrades.
As for the price of the 6870, there is one foreign site I found yesterday, starbike.com that has pricing listed now. Its the only one I could find but as has been rumored and expected, pricing will be very similar to the Ultegra 6770 group. If you don’t need the extra rear cog and minimal weight savings- there are currently some screaming deals on the 6770 group because dealers are going to want it to be all gone when the new 6870 hits the ground.
Thanks Dkevdog. This is what I’ve heard as well about the 6870; pricing should be in line with the 6770. I’d be much more interested in the 11-speed version if any of my existing wheels were compatible. . .
I purchased and was using the internal battery charger (with my iPhone power adapter) and had no idea it was also a PC interface. I needed to perform a firmware update and started to order the SM-PCE1 and discovered I already had what I needed! I thought it was kinda expensive to be just a charger. Shimano obviously does a very poor job of describing their components. . .
if you get the internal battery, you do not need the pc connector. if you get the external battery, you will need the connector to do firmware upgrade our shifting changes at home. ( but dealers are required to offer you firmware upgrade free if you buy from a local bike store)
If I want to do a tririg setup to clean up the front end(ew61 a junction with jc 40) but I also want to run an internal battery what are my options. Would I have to add the 3 or 5 port junction when wanting to charge or do an update?
Phil, you are correct. I don’t know of any stems or aerobars that can incorporate internal mounting of the SM-EW90 3- or 5-port junctions. But you would have need to temporarily attach for charging. The rear derailleur cable would be the most accessible location for attachment (assuming the cockpit cables are all internal.)
So I went and purchased the SM-BCR2 charger and an internal battery for my ultegra 6770 litespeed. I get where to put the battery, but the charger has an unusual plug on it, not the regular round DI2 etube style. How does this connect to myfshtm or o I née to swap out a our plug or junction somewhere?
K Speed: Here’s the info you need from the post above:
SM-BCR2: Charging and PC Connection for 3-port and 5-port A Junctions. This plugs into a special port on the side of the A junctions (which is covered by a rubber flap.)
Thanks Carlton, I missed that part. I’ll have to order the proper junction. Do yo know if is possible to have more than one junction in a system?
I haven’t heard of riding with 2 A junctions connected. It seems like a bad idea. If the EW-90 doesn’t fit the way you want, you could just attach it temporally when charging. The rear derailleur cable should work for this.
I have a 2014 trek 5.9 frameset which I want to put ultegra Di2 6770 on ,I’m ok with the obvious bits shifters and mechs but still confused on which wires and junctions I will need .would it be possible to provide a list of part numbers please.
I’m not sure what more information I can provide. You’ll need an “A” and a “B” junction. One of each, take your pick. Then you’ll need cables to connect everything together. (Shifters to A junction, A to B, B to battery and both derailleurs.) Measure your frame, then go longer. Longer works, but shorter won’t. It’s best to order several cables of various lengths and return what you don’t need.
Can i get a RD6870 or RD9070 to work on a 10 speed cassette ?
I would like to wait changing my Wheels but looking to upgrade my SRAM to a DI2
Anders, I’ve looked into this and see no way to change either of these from 11-speed to 10-speed mode. With 11-speeds, the maximum travel across the gears is longer and the spacing between the gears is smaller, and I can’t find any way to switch the rear derailleurs between these two requirements. Your best bet is to get a RD6770 10-speed rear derailleur now and upgrade to a new 11-speed derailleur when you upgrade wheels.
I want to use the “Dura-Ace DI2 9070 Junction Box 5-Port” for my time trial bike with the ST-9071 Dura-Ace Time Trial/Triathlon Dual Control Brake Levers/Shifters. The problem I see is that the levers come with short cable and the junction box fits under the handlebar stem. What extra cable should I use?
I have the ST-9071 levers on my TT bike. Despite what some photos show, they come with long cables. Long enough easily to route through the base bar and out to the 5-port junction attached at the stem. The manual for the levers probably shows this.
Thanks Carlton for your speedy response. Much appreciated.
Great writeup. Just one suggested change. the 6870 front and rear derailleurs are not the same as 6770. they have new smaller motors that are more efficient like dura-ace. 6770’s battery lasted half as long as da di2 and had bulkier motors. they have fixed this in the new Ultegra.
Probably a stupid question as I think that you have answered it above!
My D-Ace Di2 10-speed rear derailleur (7970) needs replacing….will the Ultegra Di2 6770 rear derailleur work? All other Dura Ace components are OK.
Thanks
No, it won’t. You’ll need to replace it with an identical 7970.
Thanks for the update. The idler arm spring is worn and not providing enough tension on the chain…..I am loathed to spend $750 on a new derailleur after 2.5 years of riding! I have been told that spares are not available. Do you have any advice?
Roger
Roger, the easiest solution is to buy an identical replacement; they’re as cheap as $520USD on Ebay. The other option would be to disassemble what you have and try to find a replacement spring; perhaps the spring RD-7900 would work, but I’m not sure. I don’t know that Shimano offers spare parts or repairs, but there is a slim chance they could help you.
Carlton- I’ve come across an interesting and weird problem. I tried using the SM-BCR2 to update the firmware on a friends Di2 6770 bike. He has the original front junction so I used the 5 port junction from mine and plugged everything in. He also has a the short cage BMR1 on a dedicated frame mount.
I was able to update all of the firmware on all of the components to add multishift capabilities but one problem. I can not for the life of me get the system to recognize nor update firmware on BMR1 battery mount. In fact, because now the rest of the components are running a higher level firmware, the battery is not even recognized by the original cockpit controller or components- which means the bike is inoperable. No shifting functions from either STI levers. He’s not too happy with me right now! I was able to get it to function perfectly (including the new multishift) using a directly connected SMBTR2 internal battery taped to the frame. He really doesn’t want to go with the internal battery option because he doesn’t want to fork out $250+ for it and the charger. Do you know if this is a known issue or problem and if there is any workaround? I’m going to try and contact Shimano today to see what they say.
That is a strange issue. I’d recommend attaching the battery directly to your Junction A, with nothing else connected, and try updating the firmware that way. There is no requirement for an internal battery. I’m guessing this may be related to having 2 Junction As in the system during programming. Were you able to update the firmware of his original Junction A that way?
We tried direct attchment and unfortunatley that didn’t work either. As a matter of fact the E-Tube Project software even suggested it adirect connection that way. The saftware keeps indicating that it is a faulty wire or battery mount, but I’m doubting that. I think its a simple firmware issue since everything suggests that all components must run the same firmware. The battery mount is the only component that didn’t update and was never reconginzed by the software. There was only one Junction A in the setup during the time of the firmware update, I removed his standard EW-67a ultegra junction do perform the programming. I didn’t have time to contact Shimano yesterday, lucky for me I am somewhat local to their Irvine office and have business down there today so I might just pay them a visit. I’ll keep you posted!
It sounds like you’ve done everything possible. Maybe it’s a bad firmware update? Your last options are to use the other diagnostic PC interface (local dealer?) or replace the battery mount.
I have the exact same issue as Dkevdog, I’ve tried it with two BMR1 long cage mounts and have the problem with them both.
Interested to see if anyone finds an answer, don’t really want to buy or hire a PCE1 just for this. Can’t help thinking it is a bug in the Shimano software.
Update- I spent some time talking to Shimano about the problem and they are aware of it. It is not a matter of firmware, it is because of the proprietary connector that the SM-BCR2 uses to connector to the 3 or 5 port junction. Apparently because the battery lacks that port, it is unable to communicate to the computer and software.
Only two options are available to solve the problem. Option #1 is to find a shop that has the SM-PCE1 shop programmer, which can connect directly to the BMR1 battery mount and update the firmware (or purchase the tool yourself and perform the upgrade)
Option #2 is of course to purchase the lighter, cleaner looking (albeit expensive) internal SM-BTR2 internal battery. My friend opted to go that route and all worked perfectly.
Shimano doesn’t advertise that the system is 6770 compatible, and while it certainly should work with all of the components, it indeed does not. It is only sold and specifically designed and marketed to charge the internal battery and perform software/feature changes on the Dura Ace 9070 or new Ultegra 6870 WHEN using the internal battery.
So there you have it folks.
Thanks for that, pretty much what I’d thought that it was something to do with the charger not being able to patch the older batteries. Still a bit annoying.
I’ve got one of the seatpost batteries and everything works with that but it is for my TT bike, so I’ll either need to patch the batteries by hiring a PCE1 or buy another internal battery, shame they are so expensive.
CArlton
Great article.. one question. I have a Mac running parallels and i have successfully installed the current version of etube project v2.3
When i connect the SM-BCR2 to the mac it makes the successful noise and and installed the simano driver.
When i launch etube it requests to connect the SM-BCR2 to the computer, which i have already done…this is where it ends.
i have tried the following 1. uninstalled the driver and reinstalled successfully again and restarted the PC – no help
in “Devices” i have disabled the Shimano device and re-enabled it as suggested by other forums – no help
FYI its Dura Ace 9070 Di2..
Any help here would be great, i have trawled the net for 2 days but nothing.
Daniel, I think this is a Parallels issue. Your best bet is to use Boot Camp or a Windows PC. This type of problem is common with virtual machines, though I haven’t tried with the Etube specifically.
All,
I’ve been successfully running E-Tube Project software on a Windows 7 Virtual Machine under VMWare Fusion, first on Fusion v.4 under OSX Mountain Lion, now on Fusion v.6 under Mavericks.
Thank you, ill give it a go
I had the same problem as daniel running Windows 7 in a Parallels VM. Windows detects the USB device and auto-installs the Shimano drivers, but the e-tube s/w doesn’t see the device. So, I downloaded VMWare Fusion, imported the Windows 7 image from Parallels, and everything is peachy now.
I was surprised, btw, at how many different pieces of firmware there are in a DA 9000 setup. Each shifter, the upper junction block, and the internal battery all have their own resident firmware that I needed to update. And this was _after_ I had to update another piece of firmware (for the charger, perhaps? I didn’t make a note), when I first started the e-tube program. Fortunately, the e-tube software makes it all quite easy.
Hi
I am just fixing Di2 7970 to my bike, but am waiting on the front mech to arrive in mail. Will the rear mech still go through motions i.e click across from using the shifters, regardless of not have connected a front mech, or is the circuit broken if the front mech is not connected?
I ask as when I put the battery in just to make sure there is power to the rear mech, the shifters are not operating the rear mech. I also have the speed shifters on the drops and they do not operate the rear mech either. The rear mech does however do its full range adjustment thing, when you press and hold down the red button on the front (handlebar) junction
Reassurance would be greatly appreciated
As I understand it, the 7970 front derailleur contains the central controller and is required. (In the newer ETube system, this was moved to the Front Junction A.)
All,
Just wanted to report back with hard evidence for any of you that wish to use a pair of SW-R600 “climbing shifters” in lieu of the more expensive ST-9071 TT brifters on the pursuit bars of your TT bike.
In my case, I’m just trying to keep a lid on my budget so I can afford to have Di2 on both my road and TT bikes. 😉
But I’ve heard of others doing this to preserve their high-zoot hydraulic brakes.
In any case, it works — just as predicted by Carlton above — at least with the new non-7970 E-Tube systems (and with a few potential annoyances, listed below for those who are thinking of trying this).
The units are a little “blocky” looking sitting there on the pursuit grips, but I’m used to them now and even imagine that they provide a bit of added stability, with more stuff to grip onto and around when I’m off the extensions.
—
Here’s what I did:
1) Upgraded the firmware and customized the function of each component in the system *individually* before connecting them together on the bike (using the standard SM-PCE1 unit).
2) Configured one SW-R600 to control the FD, and one the RD.
The principle *gotcha* is that Shimano has been less creative than we are — so assuming (or hoping) that we’d only use these in concert with the right road brifter to feather the RD, they granted them a short e-tube wire and a “handedness” to the wire exit position and mounts.
There are two consequences:
First, the wires were just *barely* long enough to snake through my base bars to the aft exit hole — but not all the way to the EW90 junction box. I solved this by plugging an SW-R600 and a SW-R671 from each side of the aerobars into an SM-JC41 junction box before sending a final short wire to the master EW90.
Second, since you’ll end up mounting both of your SW-R600s pointing inboard from the grips, they will end up not being mirror images of each other. Visually — not ideal — but no functional worry, since each button is individually customizable.
3) Finally, when I plugged my SM-BCR2 in to charge the internal battery, I noticed that the E-Tube Project software is able to recognize *both* SW-R600 units, and gives each its own icon on the display. However, unlike the SW-R671 bar-end shifters, they aren’t referred to as “L” and “R”. To change their function, you instruct the software which SW-R600 you intend to program by holding down one of its buttons for a few seconds.
—
Enjoy! And thanks again Carlton for putting together this great “missing manual”…
Hi Carlton. Thanks for this, it’s a minefield 🙂
Just one question, do you know for sure that the ST-6871 is compatible with the RD-6770 as I have read it only works with the RD-6870. Thanks
Hi Rob- That was one of my questions to Shimano when I spoke to them directly. The answer is “yes”- with one caveat- you will likely have to upgrade the firmware in the 6770 components so they are all on the same firmware. Easily done with either of the two programmers discussed here. Be aware that if you have the external battery mount BMR1 from an original 6770 setup, you will run into problems upgrading the firmware on the battery mount unless you are using the PCE-1 programmer. If you upgrade to the internal battery you will have no issues with either programmer.
I was just able to get a hold of a dealer who already has stock of the new 6870 build kit components and he is sending me one of the kits for a build I’ve been holding off on. Should have it by early next week
Thanks for the reply. I’ve been buying a few bits now and then but I’m a bit stuck now. I’m eventually planning 2 builds, a Roubaix with compact and an Argon 18 Tri bike with double. For some reason though I have bought RD-6770, FD-6770, ST-6770 and a 6700 double. I have no use for 11 speed on the Tri bike but the new slicker mech would be useful. I guess I should just buy a 6700 compact and go with the 6770 on the roubaix but 11 speed on that would be really useful!! If I stick the 6770 stuff on the Tri bike then I’m left with the 6770 sti’s but they will work with 6870 kit right? So confusing…….
So…I bought a 6870 upgrade kit for my tt bike but want to retain 10 speed capability. It sounds like I can do that by purchasing a RD 6770 and upgrading the firmware to the same version as the 6870 components. And the RD 6770 will work ok with the FD 6870?
Correct.
Great write-up, thank you. I hope you can help with a specific build. I am building up a 1×11 system by using the RD6870 GS version. I plan to use the SW-9071 or R671 bar end shifters with the ST-9071 drop shifter on right only. What ports, junctions, and cables do i need to complete the system? I can’t find any information on building the 1×11. THANKS FOR YOUR HELP!
Jim, 11-speed is the same as a 10-speed system. You’ll need whatever shifter combo you want, a 3 or 5 port junction, and cables to connect the junctions, battery, and derailleurs per the Shimano manuals.
I should add that for a 1×11 setup, all you do is eliminate the front derailleur. It’s not required (as it is in the original 7970) because the central controller is in the Junction A (instead of the front derailleur as on 7970) on second gen Etube systems.
Carlton, great information!! Thanks for the great explanation and Q&A.
I’m upgrading my mech bike to the 6870. I’ve read about several opinions about using the new 11s chain on my front chain rings. Is it necessary/required to upgrade the front chain rings to work with the new 11s chain?
Thanks!
I’m glad you found it useful! For front ring compatibility with the 11-speed chains, the answer is “it depends on the rings.” In general, most rings are probably OK. I’d recommend using the rings you have and upgrading only if you have a problem.
The bigger issue may be ring flex from the higher front derailleur shift forces. That’s the reason I upgraded from stock FSA rings to forged PraxisWorks rings, which are fantastic btw, and both 10- and 11-speed compatible.
Carlton – really useful post. Thanks.
Quick question. I damaged the wire going to the RD on my 7970. The shifting function from the right lever no longer works but the protection function goes through all the gears as expected. Does this make sense ? I would have thought that if the cable was damaged to the extent that the normal shifting didn’t work, the protection procedure wouldn’t work either. Annoying as it looks like that for the 7970 individual wires are not available – we have to buy a kit with several wires + junction and it is a bit expensive.
Thanks again for the article
Tri 04 France: Since 7970 uses 4 wires, it does seem possible that some functionality is retained by the 3 unbroken wires. Replacing the entire harness is your best option.
Can the dura ace 9070 front an rear dr multi shift with 9071 an the r671? I have this a venge with the new DA 9070 an love the setting of multi shift, an was planning building a sworks shiv module tt. I am not sure if multi shift would work on a tt bike.
My understanding of the systems would be yes, it would work. I have the R671 shifters on an ultegra 6770 system and multishift works fine with that. You will need to update firmware and enable the feature if you haven’t already. The front Junction is what controls and determines the multishift capabilities, not the end shifters themselves.
Carlton, absolutely wonderful write up!!
Hi Carlton, two quick question came up as I am building up my TM01 with Di2:
– is it okay to coil up E-tube wires that are too long and loosely zip-tie them, to prevent tangling and banging around in the frame?
– you mentioned that you have installed the internal battery in the seat-tube as opposed to the seat post itself which I very much like. Did you install it with the E-tube connection pointing up or down?
Thanks Carlton!! Again, great write-up and amazing resource for those building or working on Di2 set-ups!!
Cheers, Yoeri
Yoeri, I installed the internal battery in the frame seat tube with the connector facing down. You can coil the excess wire, but I have had no issues with just pushing the extra wire into the frame and doing nothing else.
Hey Carlton, thanks, have done exactly as you described but with connector facing up. Used a piece of wire from a hanger that I taped around the batter as ‘pull-up’ system. Works like a charm. If you ever want pictures from the set-up, I can email them to you. Might be handy if when somebody asks for it…Cheers, Carlton.
PS: this is probably the most resourcefull Di2 forum I have found.
Hi Carlton,
can you confirm that this combination should work together. An Ultegra 6770 Di2 10 Speed Rear Derailleur and an 11 speed Dura-Ace 9070 Di2 STI Shifter Set.
My mechanic says it wont and that I need to get 10 speed levers.
Thanks heaps Wally
ps: like your work
Wally, yes, it will work. A firmware update might be required.
Hi Carlton
Great article, I have just purchased shimano C50 wheels with 11 speed ultegra cassette 11-28 teeth is it compatible on my RD6770, I have tried to adjust it onto the cassette 28 teeth but it refuses to move, and not sure if chain is a problem, any advice will be appreciated.
Cheers
Jimbo
James, the 6770 10-speed derailleur will not work with an 11-speed cassette. You either need an 11-speed derailleur or a 10-speed cassette. Also, 11-speed cassettes do require a specific 11-speed chain.
Carlton
Thank you great advice, back to the drawing board, keep up the good work.
Cheers
Jimbo
Hi Carlton,
Please confirm in note 4 you say the only electronic component that needs upgrading so 6770 can be used with 11 speed is the RD, in common question you say that the FD needs upgrading as well.
Please confirm?
Thanks
Dave
Hi Dave. I should point out that the “Common Questions” are from Shimano, not me. I should update that. Shimano will tell you that for ultimate compatibility, you need to upgrade the front derailleur. If there is an advantage to doing so, I haven’t beed able to find it. A “10-speed” front derailleur functions perfectly with an 11-speed rear derailleur. If I upgrade my bike, I’ll only replace the rear derailleur (and wheel/hub/sprockets/chain.)
Carlton,
Thanks for clarifying!
I found your site a great source of information, very well written and presented, keep up the good work.
Many Thanks
Dave
Any idea when the 6870 will be available in the USA?
I’m not sure, but based on previous years, it will be April before it’s readily available in the US. I ordered parts online from Japan/Europe because I wanted to get my bike upgraded last winter and not wait until spring.
Hi Carlton – great article, thanks ….i am currently running full mech DA9000 ….can i make the jump to Di2 Ultegra 6870 Shifters / FD & RD with relevant wiring looms and internal seat post etc …and have full compatibility ? ie: with DA9000 chain rings and the 6870 Di2 FD …as an example …im just thinking …if they work interchangeably …the 6870 hardware is a fair whack cheaper ….than 9070 gear…
Cheers in advance for your advice!
Paul
You should be fine with all of your DA9000 components. The only one I would upgrade is the chain, due to the high front derailleur shift forces.
Thanks again Carlton