For internal DI2 wire routing, SHIMANO’s SM-JC41 Junction B is the central connector for DI2 systems. Wires from the front and rear derailleurs, cockpit area, and battery all plug into the 4-port SM-JC41 junction, which is housed inside the bike frame.
With a total of 5 inputs all 8 or 4 per side switching components of the Di2 groups can be connected:
– Brake / shift lever (STI)
– Lower link switch button
– Top link switch button
– Time Trial shifter or time trial brake / shift lever
Waterproof cable for Shimano Di2 shifting components. It connects the Di2 components with the junction box SM-JC40 or SM-JC41. Easy plug and play system to connect the cables, which are available in different lengths to accommodate most frame dimensions. Connection with PC for diagnosis and changing the shifting order. For questions about the length, contact the Bike24 service team. Fits all Di2 components, incl. battery excepting the Dura Ace 7970.