Time trial and triathlon cockpits rarely stop at two shifters. Between the aerobar extensions, base bar brake levers, and potentially climbing or sprint buttons, a TT build can easily need four shift points plus the connection running down to the rest of the bike. The SM-EW90-B provides five E-Tube ports to handle these multi-shifter configurations, compared to the three-port SM-EW90-A that covers standard road setups with just two STI levers.

The junction mounts beneath your stem using a rubber strap around the brake cable housing. Four ports connect to various shift inputs: primary STI levers, aerobar extension shifters, sprint buttons mounted on the drops, or climbing switches positioned on the hoods. The fifth port runs a wire down through the frame to Junction B, which distributes signals onward to the derailleurs and battery. Any unused ports simply stay capped until you decide to add more shift points later.

Like its three-port sibling, the SM-EW90-B includes an LED battery indicator activated by pressing the housing button. Green means more than 50% charge remaining, solid red indicates below 50%, and flashing red signals time to plug in the charger. The same button enters adjustment mode for derailleur indexing and handles rear derailleur crash protection reset after the bike takes an impact. With a BT-DN110 internal battery installed, the button also initiates Bluetooth pairing for wireless connection to the E-Tube Project app on your phone.... Read More