Shimano's Di2 system needs a Junction A box somewhere in your wiring path—it's the hub that connects your shifters, derailleurs, and battery. Most builds tuck it into a handlebar end, but that means running extra wire through your bars and dealing with tight routing in cramped cockpit spaces. The Cervelo Di2 Mount 294A gives you another option: mounting the junction box directly in the downtube port of Caledonia-5 and Áspero-5 frames.

The mount is a simple 2-piece composite design that clips onto both sides of a Shimano EW-RS910 Internal Junction A box. Once the junction is secured in the mount, the whole assembly snaps into the frame's wiring port hole and sits flush with the downtube surface. You get a clean external appearance with the junction box protected inside the frame rather than exposed at a bar end where it can take impacts or get snagged during transport.

Routing becomes more straightforward with the junction in the downtube. Wires from the shifters come down through the frame and connect at the junction without needing to navigate handlebar bends and stem passages. The battery wire and derailleur connections all meet at a central point that's easy to access when you need to diagnose a connection issue or swap components. If you've ever tried to troubleshoot Di2 wiring problems with a junction buried in a bar end, you'll appreciate having it somewhere you can actually reach.... Read More