Running an EW-RS910 bar-end junction with a full 11-speed Di2 setup runs into a simple problem: two ports, three things that need to plug in. The Shimano EW-JC130 Y-Split Connector solves that by consolidating two E-Tube wires into a single junction port, letting both shifters share one input while the other port stays open for a charging cable, wireless unit, or satellite shifter. It's the piece that makes internal cockpit routing work cleanly with a bar-end Junction A.

The connector is a three-legged E-Tube cable with fixed lengths — the two branch legs run to the left and right shifters, and the 50mm stub exits the bar toward the junction box. Shimano offers it in three length configurations to match different handlebar widths and routing paths: SS at 250/350/50mm, SM at 450/350/50mm, and MM at 550/550/50mm. The individual legs can't be shortened, so measure your bars with a flexible tape before ordering and size up if you're between options. Excess wire coils inside the bar without issue; a leg that's too short means starting over.

Compatibility spans every generation of 11-speed E-Tube Di2, including Dura-Ace R9150, Ultegra R8050, and GRX RX815, along with earlier 6700, 6800, 8000, and 9000 series drivetrains. It's not required for a bar-end junction install — you can daisy-chain the shifters directly — but skipping the Y-split means giving up one of the two ports on the EW-RS910, which eliminates the option to add a wireless unit, sprinter shifter, or climber switch later. For riders building around a satellite shifter setup or planning to run a D-Fly wireless unit for head unit integration, the Y-split is what keeps the port count workable.... Read More