The Shimano SM-EW90-B is the 5-port Junction A unit for Dura-Ace 9070 Di2 electronic groupsets, purpose-built for time trial and triathlon bikes that run multiple shifter inputs. It consolidates your Di2 wiring at the cockpit, delivers battery charging via a dedicated charge port, and gives you at-a-glance battery status — all in a lightweight 13 g package that mounts cleanly below the stem.

Highlights

• 5 E-Tube ports: Accommodates time trial and triathlon cockpit layouts with multiple satellite shifters — no need to daisy-chain internal junction boxes.
• Integrated LED battery indicator: Two LEDs communicate charge level instantly — green for above 50%, solid red for below 50%, and flashing red when it's time to charge.
• Dedicated charging port: Charge the entire Di2 system from a single point using the SM-BCR2 charger.
• Shift mode adjustment: A button press enters derailleur indexing adjustment mode, so you can fine-tune indexing without a laptop at the start line.
• Derailleur crash protection reset: A 3-second button hold resets rear derailleur crash protection mode to restore normal shifting after an impact.
• Below-stem mount: Secures with a rubber strap around brake cable housing for a clean, accessible cockpit position.
• Lightweight: 13 g total weight — negligible impact on build weight.

Di2 System Integration

The SM-EW90-B is the central nervous system for your Di2 cockpit. It uses EW-SD50 E-Tube wiring and connects directly to front and rear derailleurs, satellite shifters, and the battery. Firmware and synchronised shift settings can be managed via Shimano's E-TUBE software. Bluetooth pairing (where supported by the connected battery) is also accessible via the junction button.

Compatibility & Fit

Compatible with Shimano Di2 10/11-speed systems including the Dura-Ace 9070 Di2 groupset. Designed for time trial and triathlon builds requiring more than three cockpit connections. Uses EW-SD50 E-Tube cables (sold separately). Charges via SM-BCR2 charger (sold separately). Confirm compatibility with your specific Di2 groupset generation using Shimano's E-TUBE compatibility chart before purchasing.