External/Cockpit junction A

The External junction box A SM-EW90 used to be the junction box everyone had on their bikes. DURA-ACE 9150 introduced the EW-RS910 junction A, which has been the go-t0 junction box for any new bike since then.

While it is available in a 3 and 5-port version, the latter is rarely used and most people seem to opt for the 3-port version of the junction box.

You could replace this junction with the mountain bike System Information Display (XT SC-M800 | XTR SC-M9051), if you wanted to. This Information Display functions as a Junction A with three e-Tube ports, a display and features Bluetooth/ANT+ connectivity.

SM-EW90-A junction box

Details & specifications

Shimano model codeSM-EW90-A (3-ports), SM-EW90-B (5-ports)
Shimano model nameExternal/Cockpit Junction A
Weight10 g
SeriesUltegra 6770, Ultegra 6780, Ultegra R8000, DURA-ACE 9070, DURA-ACE R9150
Downloads SM-EW90-A manual
View on Amazon (new tab)  |  eBay (new tab) Chain Reaction Cycles (new tab)

Shopping links

Are you looking to upgrade your bike using this component? We've added shoppings links to this component's Amazon and eBay pages. Click the images below to view the Amazon product page or eBay search results.

Click to view on Amazon
Click to search on eBay
Click to search on Chain Reaction Cycles

SM-EW90A image