Shimano’s electronic shifting components are wonderful, ground-breaking technology that offers virtually flawless shifting and reliability, together with great ergonomics. However, Shimano Di2 is not flawless and one of the few faults I can find is has to do with the junction box.
The current 11-speed Di2 (6870 and 9070), uses a junction box (designated by Shimano as the SM-EW90) that is uses a rubber strap to mount under your stem. On a base level, the strap is not the best looking way to mount that junction box and won’t even fit under most stems that are under 9cm in length (thus requiring a “jerry-rigged” mount elsewhere). On a more functional level, the straps need to be fairly tight, and this stresses the rubber strap, so it will presumably eventually fail. Maybe this is why Shimano includes two straps with the SM-EW90. The whole “rubber strap” Shimano Di2 mount seems more like a “stop-gap” than a clean solution.
Thankfully the creative engineers at Fouriers felt the same way about the Shimano Di2 junction box mount as I did and they did something about it. Fouriers is a Taiwan based manufacturer who makes a wide variety of parts for your bike, including stems, seatposts, handlebars, chainrings and junction box mounts. Fouriers has developed a clever alloy junction box mount that goes around the steerer tube, below the stem (taking the place of 2.5 mm worth of headset steerer spacers).
The Fourier’s mount is fabricated out of 6061 aluminum and shows a fine degree of workmanship, so it should stand up to long-term use. The fit of the junction box is snug, and there is a metal spring that provides a firm grip that assures that the junction box will not come adrift on a rough road. The result is a solid, alloy mount for your Di2 box, eliminating that rubber strap around your stem. Looking at the photos, which mount would you prefer? I personally prefer the Fouriers Di2 mount on the right.
Whether you have a challenging Di2 junction box mount situation due to a short stem length or an already busy cockpit, Fouriers provides a simple and solid solution. Heck, even if you have plenty of room to use the rubber strap mount, the Fouriers mount is worth considering as it is a cleaner and more solid way to mount the junction box. Why Shimano has not come up with something like this I have no idea. Anyway, the Fouriers Di2 junction boxes is available in 6 degree and 17 degree angles, and a variety of lengths, so it should be easy to accommodate pretty much any cockpit using a conventional stem with spacers between the bearing and the stem. Clean up the cockpit of your Di2 equipped bike, and get rid of that unsightly rubber strap!
Contact us to arrange installation of an alloy Fourier’s Di2 mount or to order one.