Shimano SM-JC41

The Shimano SM-JC41 is an internal junction box (Junction B) for Shimano’s Di2 electronic shifting systems.

It serves as the central hub where wires from the front and rear derailleurs, cockpit junction box, and battery connect, facilitating seamless communication between components.

Internal Routing

Designed for frames with internal Di2 wire routing, the SM-JC41 is typically housed within the downtube or bottom bracket area.

Four-Port Connectivity

Equipped with four female connectors, it links the front and rear derailleurs, cockpit junction box, and battery mount using SD50 E-tube wires.

Compatibility

Ideal for frames supporting internal wiring. For externally routed frames, Shimano recommends the SM-JC40 Junction B.