There’s no doubt in our mind that wireless electronic shifting will happen sooner rather than later, and it’s projects like this that push us closer to the future.

Engineers from UK-based Cambridge Consultants have developed a system that communicates between Shimano’s Di2 electronic group and a smartphone (iPhone or iPad in this case) using Bluetooth Smart. You may recall from our recent conversation with Wahoo Fitness about their tech using BT Smart that it’s a very low power communication protocol, making it ideal for things where big, heavy batteries are bad, bad, bad.

The system is designed to run in either manual or automatic mode, and no, it doesn’t require you to shift from your phone’s screen. In manual, wireless shifter buttons on the handlebar let you control front and rear derailleurs like normal, albeit the signal may pass through the iPhone first. In automatic, you’d set your selected cadence and the bike would shift on its own.

How? Check the details and video below…

By measuring cadence and speed from sensors on the bike (which, coincidentally, Wahoo currently offers), the program or app would tell the bike to shift to maintain the preset cadence. The rider could adjust the desired cadence at any time manually, too. Where the system gets really interesting is when the environment changes. Using the phone’s accelerometer, it could sense braking forces and automatically downshift the appropriate number of gears depending on the severity of the slowing or stop. That way, you’d start pedaling in the right gear rather than mash through a big one until you could shift on your own…assuming you had the where with all to maintain a light pedaling action as you were slowing.

Hit a climb and the accelerometer would sense the incline and downshift according to the angle and drop in speed. That, and by accessing the iPhone’s GPS chip, it could even predict climbs and descents and pre-shift at just the right moment!

Because it controls both the front and rear derailleur, it can also prevent severe cross chaining or bad gear combos that strain the chain.

Even more interesting is the potential for training. Couple this with a Bluetooth Smart enabled heart rate monitor power meter (like Stages) and the app could very easily help keep you in a certain power range. Well, at least the right gear and cadence to give you the opportunity to stay in the right power band…making the resistance is up to you, which could be easy enough if you’re indoors on a trainer.

Two concerns remain: Interference causing unintended shifting, and dead batteries. The former shouldn’t be an issue because of Bluetooth’s frequency hopping tendencies, and the latter shouldn’t be too big of an issue because a) they say small coin cell batteries would power accessories for almost a year and b) you could always shift with your phone to get back home.

We’re also thinking it could be a boon to e-bikes to help manage power usage by adjusting the cadence and gearing.

The system isn’t for sale yet. They’ve hacked it together with a Di2 group for now, intercepting the wires and implanting a wireless receiver that takes the BT signal and electronifies it. They’re looking for interested partners to bring something to production and will display it for real at CES 2013.


  1. This is awesome! Who would have thought “automatic” style gear shifting could apply to bicycles. Next step is the option for a “R” for race mode & an “S” for social riding mode.

  2. It would make a great training tool for coaches out with the team on the road.

    Enforced gearing drills would be really much easier to implement out on the road or even on the velodrome for example. You simply dictate the gears the riders are allowed to use on the training session ..

  3. from a ‘march of technology’ perspective, this is cool. i want to see something like cadence sensors plus pedal power meters plus a mini computer in the shifters to process it all and you could have a super smooth, automatically shifting bike. i like my cable shifters just fine but it’s neat watching people take this tech wherever it can go.

  4. as one who drives a desk and computer during most of my work day, the last thing I want along on my rides is a f*ing computer doing a job (shifting) that for the most part is completely reflexive and natural to me.

    no.. ..It’s an interesting little project but not for me.

  5. Like most things computer and smartphone, it’s needlessly complicated and could not possibly justify the additional expense.
    If you were handicapped, maybe this would be different.

  6. What’s the point, there will be almost no weight savings if transferred to a normal bike and the technology is more difficult to fix in the event of damage or a crash.

  7. Another “solution” in search of a problem. It could possibly benefit handicapped people unable to operate shifters, but what real bike rider wants to be forced to shift gears ? I’m sure the people involved are having fun from a “look what we did” perspective, but not very practical in the real world.

  8. @Homebrew I completely agree. additionally, with power at 100watts, things start to get noisy when shifting. what happens when you are sprint and you are at 1000 or 1500 watts? no! As a software engineer, I’m inclined to believe that the limitation lies in the programmers abilities but this just seems dumb. this is like buying a Ferrari and lifting it, putting big tires on it so you can go over speed bumps faster.

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