Shimano Di2 SM-EW90 Junction A

The Cockpit Command.

The SM-EW90 is designed for easy, external mounting, typically secured under the stem with a durable rubber strap. It acts as a hub for your EW-SD50 wires, collecting signals from your dual-control levers and transmitting them to the battery and derailleurs. Beyond its role as a connector, it features an integrated charging port and a tactile button that allows you to check battery levels and adjust your derailleur alignment on the fly.

Why the SM-EW90 is a Build Essential:

• On-the-Fly Adjustment: Features a small button and LED indicators that allow you to enter "Adjustment Mode." This lets you fine-tune your rear derailleur alignment while riding, ensuring perfectly silent shifting in every gear.

• Integrated Charging Port: Works seamlessly with the SM-BCR2 USB Charger, allowing you to top up your internal battery without removing a single part from your bike.

• Battery Level Indicator: A simple press of a shift button illuminates the LEDs on the junction box, giving you instant feedback on your remaining battery life (Solid Green, Flashing Green, Solid Red, or Flashing Red).

• Flexible Port Options: Available in two configurations to suit your cockpit needs:

  • SM-EW90-A (3-Port): Perfect for standard road setups with two shifters and one lead-out wire.

  • SM-EW90-B (5-Port): Ideal for time trial/triathlon bikes or road bikes using additional "sprint" or "climbing" shifters.

• Reliable E-Tube Connection: Uses the industry-standard SD50 ports, ensuring a waterproof and vibration-resistant connection that won't fail during intense efforts or inclement weather.

• Low-Profile Design: Lightweight and compact, it stays tucked out of the wind and out of the way of your hands, maintaining the clean lines of your performance build.

Technical Specifications:

• Model: SM-EW90-A (3-Port) / SM-EW90-B (5-Port)

• Compatibility: All 10 and 11Speed E-Tube Di2 systems

• Mounting: External (Stem strap included)

• Ports: SD50 E-Tube type

• Function: Battery check, system charging, and derailleur adjustment

• Weight: ~10g (A) / ~13g (B)

The Alegro Perspective: The SM-EW90 is the "classic" Di2 junction. While the newer EW-RS910 offers a hidden look, the EW-EW90 remains the favorite for mechanics and racers who want easy access to the adjustment button and charging port. It is robust, simple to install, and has been proven in thousands of pro races. If you're building up a reliable Ultegra R8050 or GRX 815 rig, this is the most straightforward way to get your cockpit connected.

Accessible Intelligence. Simple Integration. Power your Cockpit with Shimano.