The best way to connect aerobars with Di2-shifters to bike w/ Ultegra 8000 Di2 and the junction box

t0tte Posts: 5
edited August 2019 in Workshop
The current installation (performed by the supplier) of the junction-box (EW-RS910) results in only one port left at the levers for what's usually used for sprint or climbing shifters. This port is found at the left lever (ST-R8050 L).

Can I get Shimano's four-port junction-box (SM-JC41), plug in the aerobar shifters (SW-R9160), and connect one of the remaining two ports of the junction-box with a wire (EW-SD50) to the available port on the left lever and thereby make it work?

Is there a better way, even if it works?


  • As long as they're all connected in series some way, I don't think it matters just how they're wired
  • StillGoing
    StillGoing Posts: 5,211
    I have the EW-RS910 bar end junction. I take an EW-JC130 lead from it with one end to the R shifter and one end to the L shifter. One lead from the L shifter to junction B in the BB connecting the Battery (via EW-WU111) and both derailleurs. Each shifter has a sprint button attached.

    If instead you took an EW-JC130 lead from the EW-RS910 to the left shifter and to an EW-WU111 with a lead from that to junc B, and a separate lead from EW-RS910 to the right shifter, you could fit the sprint shifters and that leaves a spare port in both shifters for your aero bars.

    See page 29 of the attached manual link.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.