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Shimano Di2 SM-JC41 Junction B
  • Shimano Di2 SM-JC41 Junction B
  • Shimano Di2 SM-JC41 Junction B
Shimano Di2 SM-JC41 Junction B

Shimano Di2 SM-JC41 Junction B

$50.00 CAD

The Hidden Hub.

The SM-JC41 is a simple yet vital piece of the Di2 puzzle. It features four ports that utilize EW-SD50 wires, allowing you to centralize all your connections in one protected location. By housing these connections internally, you protect your system's digital signals from road spray, grit, and accidental impact, ensuring your shifting remains perfect even in the most grueling conditions.

Why the SM-JC41 is a Build Necessity:

  • Centralized Internal Routing: Designed to be hidden inside the frame's tubes (usually the down tube or bottom bracket shell), creating a completely clean aesthetic with no visible wires between the main components.

  • Four-Port Versatility: Equipped with four SD50 E-Tube ports, typically used to connect:

    1. The Front Derailleur

    2. The Rear Derailleur

    3. The Battery (Internal or External)

    4. The Junction A (Cockpit connection)

  • Ultra-Compact Design: Small enough to fit through almost any standard bottom bracket shell or frame port, making the assembly process easier for mechanics and home builders.

  • Weather-Sealed Reliability: Because it is designed for internal use, it provides an extra layer of protection for your digital connections, ensuring a consistent signal through rain, mud, and stream crossings.

  • Universal 10/11Speed Compatibility: Compatible with all E-Tube Di2 systems using SD50 wires, including Dura-Ace 9070/9150, Ultegra 6770/6870/8050, and GRX 815.

  • Zero Maintenance: Once installed and connected, the SM-JC41 requires no power or configuration. It is a passive, reliable hub that simply works.

Technical Specifications:

  • Model: SM-JC41

  • Type: Junction B (Internal)

  • Ports: 4 x SD50 E-Tube ports

  • Compatibility: 10/11Speed Di2 Systems

  • Mounting: Internal (No hardware required)

  • Weight: ~4g

The Alegro Perspective: The SM-JC41 is the "unsung hero" of a clean Di2 build. It’s a tiny, inexpensive part, but it’s what makes internal routing possible. In the shop, we always remind riders that if they are upgrading a frame to 11Speed Di2, this is the one part they cannot forget. It’s what turns a collection of parts into a cohesive, high-performance machine.

Seamless Integration. Protected Connections. Simplify your Build with Shimano.

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