Trek Domane Team Issue Race Shop754

Earlier this year, Shimano’s D-Fly wireless transmitter plugged into the Di2 system to wirelessly send information to an ANT+ cycling computer and relay gear selection, gear ratio, etc. Now, our friends at told us there’s a button hidden under the top of the hoods on Dura-Ace Di2 9070 shifter levers that until now has been unused.  That button sends a distinct wireless signal to those same computers to do, well, something.

Garmin, Magellan, Pioneer and Shimano PRO are those already integrating the gear info, so it’s no stretch to imagine they’ll be among the first to use the button to cycle through functions and screens.

But what if this were ported over to mountain bikes?

Shimano Dura ace di2 hood button computer control e tube (1)

We had a Trek Domane review bike in with 9070 and took a quick peek under the rubber. Sure enough, there’s a button on each side just under the top of the hood, where the rubber is soft enough and shaped to depress this little guy:

Shimano Dura ace di2 hood button computer control e tube (3)

The button looks small, but our own finger pressing suggests it works perfectly. We reached out to Shimano and Pioneer but haven’t heard back (updates if we do). But we did speak with Sam at Magellan and Amy at Garmin:

Magellan: “I can’t really talk about it too much because it’s under development, but suffice to say we’re working with Shimano to integrate levels of functionality to control the head unit.”

Garmin: “We’re working on integrating this capability into our devices for an upcoming software release.”

Given the announcement only came this week, their brief responses and the others’ lack of isn’t surprising – no one’s had time to update their firmware to take advantage of it. For now, the functionality is only for road bikes since (as far as we know) there’s no such hidden button on the new XTR Di2 group. And, according to Shimano’s information, D-Fly is only for the road-going Di2 groups. But, D-Fly is an e-Tube plug-in accessory, and XTR Di2 uses e-Tube…so, we’re thinking an accessory button or 3rd party hack isn’t too far off.

And the applications there are even more practical. Both Magura and Fox already using electronic lockout systems for their fork and shock. Fox’s iCTD/iCD system is already integrated into the new XTR controls, letting you assign one of the shifters to work the remote instead of the drivetrain, but it’s all wired. Imagine that going wireless!

Magura’s system already is wireless, and the latest generation uses ANT+, and ANT+ recently announced an open suspension protocol. We spoke with their US tech rep and he said he wasn’t aware of any development on that front, but the idea was certainly intriguing. That said, the premise of their system is that it locks out automatically when needed, so manual control isn’t the highest priority there.

Either way, road or mountain, this certainly opens the door to some pretty killer possibilities for controlling any ANT+ device. What would you have it do?


  1. Seeing as you can trigger their Virb camera using the Edge Remote, it would be great (on the dirt) to see Garmin take advantage of a shifter button to start/stop a helmet cam.

  2. The DA 7900 Di2 levers also have those buttons in.

    (Was supposed to control the Flightdeck computer I think). So the button itself has been around since the dawn of electric gears.

  3. I never noticed this on my bike until I read this post. I just upgraded to the garmin 810. I really hope Garmin/Other developers put some thought into this and what would be useful. Switching screens isn’t really needed, specially with my 810 as it has everything on one screen.

  4. I cannot wait until it pairs with the Shimano camera. Throw them cameras in the peloton and start and stop filming from the hoods. Some of the best road racing footage is captured from the riders perspective, especially criterium racing.

    But, until it has a beer ready and waiting for me at the end of my ride, I’m just another keyboard expert commentator.

  5. That button could control a super-secret EMP weapon which fries everyone’s electronic whiz-bang gizmo bikes – also a self-destruct button, in that case, of course. Make sure you like your single-speed ratio before taking out the whole peloton! Heh-heh-heh…

  6. Newsflash for Shimano: Zipties are fugly.

    Now that there is an actual implementation for it, the wireless functionality of the EWW01 needs to built in to the front junction boxes (EW90-A/B).

  7. @Darren – nope, my guess is that first gen 7970 will not work – main reason is the change in the wiring. If I’m remembering things correctly, the original Di2 used a larger connector and there are more wires inside of each cable (or may vary by cable, etc); the new gen (Ui2 gen 2 11 speed for sure and the new Di2 gen 2, 11 speed) all use a two wires in the cable, smaller connector that ties into a single “bus”… so now things chat with each-other via various pulse rates, or frequencies within the “bus”. Unless they create some sort of converter (and who knows, maybe it is out there) I don’t think the new D-Fly wireless transmitter will connect/communicate with the old 7970 Di2…

What do you think?