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Shimano - E-Tube Di2 Junction Box

Shimano E-Tube Di2 Junction Box

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$20.37 $32.99

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    • One Color, External/SM-JC40
      sale $20.37
    • One Color, Internal/SM-JC41
      sale $20.37

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    Warning: California Proposition 65

    California Proposition 65

    Warning:

    Cancer and Reproductive Harm - P65Warnings.ca.gov

    Tech Specs

    Crankset Compatibility:
    2 x 10
    Compatible Components:
    Shimano Ultegra Di2
    Recommended Use:
    ditching your mechanical tethers
    Manufacturer Warranty:
    2 years

    It’s time to connect.

    Shimano’s E-Tube Di2 Junction Box (also known as the B junction) connects all your component and battery wires to make assembly much easier. It's a crucial item along with the five required wire sections to operate your Ultegra 6770, Ultegra 6870, or Dura-Ace 9070 Di2 shift system. The E-Tube Di2 Junction Box is available in two configurations: Internal (SM-JC41) and External (SM-JC40).

    • Connects Di2 cycling component and battery wires
    • Available in external or internal configurations
    • Shimano's Di2 is the most popular electronic drivetrain in the pro ranks

    Shimano

    Di2 Reference Guide
    Battery and Wires: Our Shimano Di2 packages are built for three standard configurations based on battery location and wire routing. First, you'll need to determine if your frame uses an internal or external battery mount, and whether the routing is either internal or external. Below is a guide for which battery, charger, mount, and junction boxes are required for your configuration.
    Battery & Wire ConfigurationsBatteryBattery ChargerBattery MountJunction AJunction B

    External Battery

    with External Routing

    SM-BTR1

    SM-BCR1

    SM-BMR2

    SM-EW90 A/B 3/5 port

    SM-JC40

    External Battery

    with Internal Routing

    SM-BTR1

    SM-BCR1

    SM-BMR2

    SM-EW90 A/B 3/5 port

    SM-JC41

    Internal Battery

    with Internal Routing

    SM-BTR2

    SM-BCR2

    		  

    SM-EW90 A/B 3/5 port

    SM-JC41
    Battery Mounts: The SM-BMR2 battery mount is available in three configurations -- Long External, Short External, and Long Internal. Both Long versions are to be mounted using the bottle cage mounts, while the Short version is designed for Di2-specific frames with either a chainstay or down tube mounting location.

    Junctions: There are two junctions needed for completing your Di2 build -- A and B. Junction A, SM-EW90, is located at the handlebars and available in both three- and five-port options. The three-port option is intended for standard shifting with a left and right hand shifter. If you have the intention of using Shimano's satellite sprint shifters, or a combination of time trial shifters and shifter/brake levers, the five-port junction box will be the necessary selection.

    Depending on your frame specification, Junction B (SM-JC40 or SM-JC41) is located either internally or externally at the bottom bracket area. Accordingly, SM-JC41 is designed for frames with internal wire routing, while SM-JC40 is intended for external wiring options.

    E-Tube Wires: For your convenience, we've created wire packages for your Di2 build kit in the sizes Small, Medium, and Large. Below, you'll find which wire lengths are included in each kit. Additionally, we've recommended a kit size based on your frame size.
    E-Tube Wire Length ChartSML
    Down Tube Wire

    700mm

    750mm

    950mm
    Front Derailleur Wire

    300mm

    350mm

    400mm
    Rear Derailleur Wire

    500mm

    550mm

    600mm
    Battery Wire

    300mm

    350mm

    400mm
    Note: E-Tube Wire Length Suggestions are an approximation.
    E-Tube Wire Frame Size Guide

    S

    M

    L

    Frame Size 47 - 52cm 53 - 56cm 57cm+
    Note:
    This reference is meant to be used as a guide for creating a Shimano Di2 drivetrain package. For further assistance please feel free to give us a call.