Shimano EW90-A Di2 Cockpit Junction Box 3-Port
What Does the Shimano EW90-A Di2 Junction Box Do?
The EW90-A is the cockpit-mounted 3-port junction box for older Shimano Di2 systems, specifically the Dura-Ace 9070 11-speed Di2 generation. It serves as the central hub where the EW-SD50 wires from the STI levers, front derailleur, rear derailleur, and battery converge at the handlebar. The three ports accept the left lever wire, right lever wire, and a downward run to the rest of the drivetrain. It also provides the interface for the SM-EW67-A PC connection port used for firmware updates and system configuration via Shimano's E-TUBE Project software, keeping all system management accessible at the cockpit.
The EW90-A mounts under the stem or along the handlebar depending on the build, and its compact housing keeps the junction tidy and protected from impacts. A key requirement for the entire Di2 9070 system: all connected components must run matching firmware versions to communicate correctly and shift reliably. Mixing firmware versions across levers, derailleurs, and the junction box causes communication malfunctions. The EW90-A is the OEM front wiring kit component for Dura-Ace 9070 and remains in active use on many older high-end road builds. If you are servicing or rebuilding a Dura-Ace 9070 Di2 system, this is the correct junction box for the cockpit.
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Shimano EW90-A Di2 Cockpit Junction Box 3-Port
Shimano EW90-A Di2 Cockpit Junction Box 3-Port
What Does the Shimano EW90-A Di2 Junction Box Do?
The EW90-A is the cockpit-mounted 3-port junction box for older Shimano Di2 systems, specifically the Dura-Ace 9070 11-speed Di2 generation. It serves as the central hub where the EW-SD50 wires from the STI levers, front derailleur, rear derailleur, and battery converge at the handlebar. The three ports accept the left lever wire, right lever wire, and a downward run to the rest of the drivetrain. It also provides the interface for the SM-EW67-A PC connection port used for firmware updates and system configuration via Shimano's E-TUBE Project software, keeping all system management accessible at the cockpit.
The EW90-A mounts under the stem or along the handlebar depending on the build, and its compact housing keeps the junction tidy and protected from impacts. A key requirement for the entire Di2 9070 system: all connected components must run matching firmware versions to communicate correctly and shift reliably. Mixing firmware versions across levers, derailleurs, and the junction box causes communication malfunctions. The EW90-A is the OEM front wiring kit component for Dura-Ace 9070 and remains in active use on many older high-end road builds. If you are servicing or rebuilding a Dura-Ace 9070 Di2 system, this is the correct junction box for the cockpit.
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
What Does the Shimano EW90-A Di2 Junction Box Do?
The EW90-A is the cockpit-mounted 3-port junction box for older Shimano Di2 systems, specifically the Dura-Ace 9070 11-speed Di2 generation. It serves as the central hub where the EW-SD50 wires from the STI levers, front derailleur, rear derailleur, and battery converge at the handlebar. The three ports accept the left lever wire, right lever wire, and a downward run to the rest of the drivetrain. It also provides the interface for the SM-EW67-A PC connection port used for firmware updates and system configuration via Shimano's E-TUBE Project software, keeping all system management accessible at the cockpit.
The EW90-A mounts under the stem or along the handlebar depending on the build, and its compact housing keeps the junction tidy and protected from impacts. A key requirement for the entire Di2 9070 system: all connected components must run matching firmware versions to communicate correctly and shift reliably. Mixing firmware versions across levers, derailleurs, and the junction box causes communication malfunctions. The EW90-A is the OEM front wiring kit component for Dura-Ace 9070 and remains in active use on many older high-end road builds. If you are servicing or rebuilding a Dura-Ace 9070 Di2 system, this is the correct junction box for the cockpit.
