Shimano SM-JC41 Di2 Internal Frame Junction Box 4-Port

The Shimano SM-JC41 Di2 Internal Frame Junction Box (4-Port) is a compact internal routing hub that connects key components of Shimano Di2 electronic shifting systems. It links up to four SD50 E-Tube wires, including the front derailleur, rear derailleur, cockpit junction, and battery connection, enabling seamless communication between all drivetrain elements.

Designed for internal frame integration, the SM-JC41 helps keep wiring clean, protected, and efficiently routed inside the frame for a streamlined setup. For optimal performance, Shimano recommends ensuring all Di2 components are running compatible firmware versions to avoid communication issues. Firmware updates and system checks can be performed using the Shimano E-Tube Project platform.

Key Features

• 4-Port Di2 Connectivity – Connects front derailleur, rear derailleur, cockpit junction, and battery via SD50 E-Tube wires.
• Internal Frame Integration – Keeps electronic shifting system wiring clean, protected, and neatly routed inside the frame.
• System Firmware Compatibility – Works with Shimano E-Tube Project for firmware updates and system diagnostics.