Shimano's Secret Black Box
Jul 11, 2013
article & images by Nick Salazar
I've said it plenty of times: Shimano's new E-tube platform for the Di2 component groups is the best thing that ever happened to electronic shifting. Not only did it bring improvements like smaller connectors, no-fuss waterproofing, and lighter weight, but it represents Shimano's commitment to keep the same wires for the foreseeable future. This means once you go through the relative headache of doing all the wiring, you can basically just upgrade the extremities of your drivetrain, leaving its nervous system intact.
Regrettably, the newest wiring junctions leave a bit to be desired in terms of minimalism. The big 3-port and 5-port junctions (part numbers SM-EW90-A and SM-EW90-B) are big and bulky, and don't do a good job of hiding out of the way like the original "Junction A" on the first-generation Di2 7970. Moreover, in snazzy little stem compartments like the one built into the Trek Speed Concept, and our own TriRig Sigma, the new boxes are too bulky to fit. Shimano, it seems, wants you to run them external, taking away the ridiculously-awesome aesthetic of a totally-hidden Di2 installation.
But fear not, dear readers. I've not only found out how to hide Di2 6770 and 9070 (the latest e-tube systems) within a TriRig Sigma stem, but basically bring back the minimalism of that original Di2 junction box, making it MUCH easier to make custom hidden Di2 setups on virtually any bike you like. Before we proceed, let's stipulate that getting into the nitty gritty of Di2, the component numbers, and frame modifications in general is not a topic for the faint of heart. Casual readers, you can jump overboard right now, because it's only going to get more geeky from here.
If you're still with us, of course, it means you want to know what's up with e-tube, and how to make it a bit sleeker. The answer is simpler than you think. It doesn't require any soldering, any electronics know-how, and involves nothing more than the clever use of one of the coolest little components in the e-tube universe. Hit the jump to find out why my favorite new bike part is a tiny black box known as SM-JC41.