Shimano D-Fly SM-EWW01 Di2 ANT-plus wireless transmitter

Rumored since Interbike last year, Shimano’s D-Fly wireless transmitter for E-Tube Di2 systems is finally official.

The minuscule ANT/ANT+ transmitter will plug inline anywhere in the system, providing plenty of mounting options. The unit will transmit system data like battery level, gear selection and a few other items, to compatible cycling computers. Initially, that’ll only be the new Shimano Pro SCIO ANT+ Cycling Computer, but units from MIO and others are on deck for spring 2014.

Essentially, the SCIO/D-Fly combo are bringing back some of the best Flight Deck features, namely showing what gear you’re in. Presumably, it’ll also show (or at least be able to show) the gear ratio and calculate cadence based on speed and gear selection.  Full features list is yet to be released for the computer.

UPDATE #1: It can be installed anywhere inline, not just at the rear derailleur. But, it’s not recommended to install it inside a tube or stem as that could create interference or limit signal transmission and negatively affect performance. More updates as we get them.

Beam past the break for a closeup photo and more…

Shimano D-Fly SM-EWW01 Di2 ANT-plus wireless transmitter

Actual size is 38mm x 25mm x 12.5mm. Weight is less than 5g. The unit will work with DA9070 and Ultegra 6870 and 6770 and is powered by the regular system battery. It ships in March for $79.99.

The SCIO computer ships in February in white or black for $139.  Given the price compared to prior SCIO models, we suspect it’ll have all the bells and whistles like Altimeter, but not GPS. All the more reason to be excited that other computers will soon have access to their protocol. Because it’s ANT+ also, it should be able to pick up data from other sensors. Claimed weight on that is 80g, more on that as soon as we get it.


As of now, it won’t allow you to control your system wirelessly. That doesn’t mean it’s not ever going to do it – theoretically, it’d just be a different set of commands sent to the device. But that assumes it can receive as well as transmit. No word on whether it can or can’t, and we’ve asked.

Assuming it does, here’s your group ride discussion of the day: Sould it really be practical to have to worry about so many separate batteries on each shifter just to remove a few wires?

We could see training applications that could take advantage of it, such as letting your coaching program/app shift for you to adjust cadence and/or intensity…on the trainer, of course. Not on the open road.

Shimano’s using a private ANT protocol, meaning they control what data is sent. Check out our interview with several ANT+ consortium members for an in depth look at how that works. In a nutshell, it means Shimano can easily limit who can access that data. It also means they could limit access to shifting controls.


  1. Mr X. on

    Nice. Technically, any Garmin or X brand’s head unit supporting ANT should be able to display the data with just a firmware update, correct?

  2. Neb on

    Is it broadcasting the information on standard public ANT+ and private-ANT or purely only private-ANT? If I understand the protocol correctly, the latter would require that Shimano give the keys to accessing the private network; requiring some sort of licensing scheme, I would imagine.

  3. David French on

    This seems a little bit backwards. Wouldn’t it be easier if Shimano were to put it up with the little control box which usually sits up by the handlebar?

  4. McClain on

    I’m still not interested in electrical groups but stuff like this is in the direction I’ve been waiting to see. A) why couldn’t this be built-in to the derailleur unit? B) how long before E-Groupsets are entirely wireless? I’m no engineer but it doesn’t seem that difficult.

  5. Ben on

    Still a few long wires there, seems a bit disingenuous to be calling it wireless? Wireless would be nice but then the multiple battery issues. Still love my cables.

  6. Scott Garrett on

    Back in 99 I ran the Mavic Mektronic wireless system. It had two additional change buttons and integrated CR2032 camera batteries in the derailleur and computer head unit. Had it not changed gear at random on wet days it would have been brilliant and we wouldn’t have had to wait so long for this discussion about full wireless. Point is, if you’re happy to move away from rechargeables and carry a 2g spare battery in your pocket, the 4-battery argument really doesn’t matter.

  7. maddogeco on

    I would love to know the data of what gear is was in verse my speed and cadence. I think my cadence is too low so this could help me analysis my ride better. If the GPS know there was a step hill ahead it could auto shift for you to the best gear for your training plan.

  8. Gunnstein on

    Computer/smartphone control of gearing might be more interesting once this trickles down to recreational/touring/commuting usage. A computer can convert a dual derailleur 3×10 setup to a virtual 1×14, with one shifter controlling the whole range, shifting front and back and doing recovery shifts as needed without the user needing to know the details. Optional cadence based fully automatic gearing could easily be added. (Top athletes want complete control, so this is not for them.)

  9. Gumby on

    Read my comment regarding the internal battery for Champy… perhaps McCain has as he references one of the concepts I brought up.
    This news release further underscores the type of future development that I predicted. Once the functions are integrated into the Di2 with firm wear upgrades there will be a generational (iv?) roll out of blue tooth…

    Oh multiple batteries not necessary see my comments on the Shimano Battery currently power MTB seat posts and shock settings.

    A few insightful comments here are camouflaged by people that have nothing to add but rhetoric. Have take and don’t suck!

  10. ranggapanji on

    I won’t mind four batteries if that means less cables cluttering the cockpit area!

    or I can just build a singlespeed/fixxxie instead.

  11. Jack on

    Really is this anywhere near needed? Could Wireless get confused possibly lead to someone wirelessly changing gears for you? Anyhow your road bike will never be totally wireless unless you don’t use brakes. I have one wireless bike. I use it on the track.

  12. Shanghaied on

    @Jack, no one worries that their wireless HR is reading someone else’s heart rate, or that their wireless computer is displaying someone else’s speed, or their wireless phone is sending someone else’s text, so I don’t see how it would be a problem here.

    Four batteries are just not practical, but I can easily imagine two batteries, one large rechargeable one for the power-hungry derailleurs and one small replaceable lithium cell for the the shifters and computer, with wireless connection between the two groups. Car keys and garage door openers use small lithium cells and they last a long time, and you can easily bring a spare or two.

  13. ve on

    “that their wireless computer is displaying someone else’s speed”
    I worry that my computer receives interference and acts wonky. Fortunately it has next to no effect on my safety and can no cause any sort of catastrophic failure.

    Di2 shifting from big ring to small ring unexpectedly while standing on the pedals. Maybe.

  14. Jack on

    @Ilikeicedtea Last time I looked there were lines running from the lever to the calliper on Hydraulics. So yes, not cables but the same amount of clutter. If you know of remote (disconnected) controll hydraulics for a bicycle (no hydro lines) you must be an industry insider.

  15. McClain M on

    @Gunnstein and Gumby:

    I envision something like a mat you hang on a wall, that you could lean the bike against so that all the major components would charge by Induction like some modern phones can do… you might have to have some cross over between the levers to keep them on a singe combined battery. But with battery tech advancing so quickly (i.e.: Graphene!), making long-lasting and powerful enough batteries doesn’t seem like a difficult engineering feat at this point, just a matter of time.

  16. NikH on

    If you could have the current 1000km approx recharge requirement of Di2, I’d be happy with having to plug in four wires to recharge a fully wireless system. You would just need a specific charging ‘spider’. There’s no need for your battery to go flat with current DI2 as you have an LED indicator. If a wireless system added a phone like battery status to your phone/head unit you have no excuses.

  17. John on

    @David French: Agree. Build this into the SM-EW90 Cockpit Junction boxes and be done with it.

    Just a guess, but I figure Shimano would make a lot more money selling additional Di2 systems to people wanting gear selection data via open ANT+ standards than they will selling gimped SCIO bike computers with a private ANT protocol.

  18. Michael on

    i have a shims I d fly paired with Magellan cyclo 315
    In the gear position readout, it reads the rings right to left so 1-1 is the big front ring and small back ring
    Is there a way to reverse the gear position readout so 1-1 is the easiest gear, not the hardest


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