University team develop wireless braking system for bikes

...and it'll only fail three times in a trillion.

by Dave Atkinson   October 14, 2011  

Holger Hermans demonstrates the wireless braking system (pic courtesy Saarland University)

Whenever talk turns to Ultegra Di2 or the new Campag electronic groupset round these parts, there's always the nagging question: why isn't it wireless? There are two main reasons why until now the shifting companies have stuck with wires: It's less battery intensive and the wires ensure reliability of communication.

We've all had a wireless bike computer go a bit haywire thanks to a certain LED light, or a substation, or another bike computer, or a traffic light loop, or... well, the list goes on. It's no big deal if you don't know how fast you're going for a few seconds, but to miss that vital gear change in a sprint to the line is a different matter.

Problems like that are a challenge to scientists, and one man who's been taking up the challenge is Professor Holger Hermanns of Saarland University. He's been working to develop not wireless gears, but wireless brakes; if there's any system on your bike that needs to be fail-safe, it's the anchors.

"Wireless networks are never a fail-safe method", says Hermanns. "That's a fact that's based on a technological background." Nevertheless he's been working with a group of scientists to develop wireless systems that function full-time with no interruptions, and the humble bike brake has been his testbed. Actually the team are working to develop protocols and systems for much more complicated and mission critical systems for trains, aeroplanes, chemical plants and the like. But obviously you don't want to be experimenting on an airliner at 32,000 feet. Hence the bike.

The system is a disc brake, actuated remotely by a pressure-sensitive grip. The harder you squeeze, the more braking force you apply at the wheel. The braking command is sent simultaneously by a number of transmitters to reduce the chance of a lost signal.

Using the same testing algorithms they'd employ for checking those more complicated systems, Hermanns' team have managed to create a wireless braking system that's 99.999999999997 percent reliable. "This implies that out of a trillion braking attempts, we have three failures", says Hermanns. "That is not perfect, but acceptable."

Acceptable indeed. If you brake once a second, that's one failed attempt every [breaks out calculator...] 10,000 years or so. But aside from being a testbed for technology to be used in more complex processes, does the wireless brake have any practical applications for bikes? On its own a wireless brake doesn't really have any advantage over a wired one, but one of the spin-off benefits is that the system used can be configured to include feedback loops for anti-lock braking. "That takes only a few adjustments", says Hermanns. The working group have been talking to brake manufacturers and are looking for engineers to help realise the concept. There's no reason to think that other control commands, such as those for shifting gears, couldn't be integrated into the same or a similar system, suggesting the possibility of a completely wire-free bike.

Judging by the pic of the prototype, the wireless technology requires some fairly heavy duty batteries and actuators; after all, stopping a bike and rider takes considerably more effort than shifting from one sprocket to the next. In all likelihood the technology will only have any kind of practical application in e-bikes, at least for now. Road bikes will be sticking with wires, of the mechanical or electronic kind, for the time being...

Thanks to Joss Benyon for the link!

15 user comments

Oldest firstNewest firstBest rated

OFFS! Just give me cables!

Exercising my rights by taking them cycling

posted by pedalingparamedic [94 posts]
14th October 2011 - 12:46


No thanks

posted by John G [53 posts]
14th October 2011 - 12:57

1 Like

I wish people would stop trying to re-invent the wheel!

ralphred1965's picture

posted by ralphred1965 [12 posts]
14th October 2011 - 13:16


Oh for fuck's sake guys. It's an in-principle development of technology for other purposes. The fact that they used a bike is just coincidence and (for them) convenience. Nobody is even developing it for a market. It's kind of a cool bit of technology, but nobody's even thinking of trying to sell it to you. Please, please, get off the high horses.


posted by stewieatb [299 posts]
14th October 2011 - 14:20


Imagine how smart a fixie would look with no cables! Will be a long time before any boffins figure out how to minaturise the motors that apply the braking force so we won't be junking our cables any time soon.

posted by moonbucket [60 posts]
14th October 2011 - 14:27

1 Like

I applaud it.

I'm happy for those above who don't to continue to walk barefoot everywhere. Naked. And have no tv or homes.

It's r&d and technological advancement, not a current product. If this sort of tinkering wasn't happening we'd not even exist as a species right now.

posted by the-yorkshire-p... [180 posts]
14th October 2011 - 14:30


This isn't a dig at the tech but at those Safety statistic claims with this and so many things. 3 fails in a trillion. Now if you can guarantee that those three occur at 1 trillion -3, 1 trillion -2 and 1 trillion -1 I'd be happy.

I accept, vanishingly small but not impossible that it will happen as I barrel towards a cliff edge. I wonder what the statistics for a normal brake failing. Probably more than 3/trillion. I wonder if the claim is for the new tech failure or the total system? eg wirelss works, brake pads shoot out of calliper.

God I'm bored.

posted by 1961BikiE [112 posts]
14th October 2011 - 15:58


Test only. Not production. Besides, it hasnt won the IG Nobel prize yet...

HK phooey no.1 super

redthing's picture

posted by redthing [26 posts]
14th October 2011 - 20:38

1 Like

remember, one in a trillion is probably less frequent than a snapped cable, bolt or lever.

tech = good
implementation = bad.

posted by thehood [25 posts]
15th October 2011 - 0:28


This is what people said when people started with electronic shifting..

Now look what the pro's use, and everyone else drools after..

seabass89's picture

posted by seabass89 [235 posts]
15th October 2011 - 14:49

1 Like

When are we going to get computer controlled automatic electronic shifting based upon electronically monitored cadence input...or should we stick to fixies Smile

posted by batch [60 posts]
15th October 2011 - 22:29

1 Like

it'll be RC Bikes next, they'll be really fast because you'd be sat at home on your iwhatever, controlling them. then you'll virtually go to the cake shop or pub and go to your mates "I was quicker than Cav today, easy!"

Currently going slower than I'd like...

posted by stealth [258 posts]
16th October 2011 - 17:30

1 Like

Not impressed. Where's on earth is the chain free chain set? Save me loads of time cleaning a chain not to have one - not to mention the all important saving in weight and the opportunity to ride a bike wearing white flares as we'd all like to. Big Grin

Silly me. You're probably right....

MercuryOne's picture

posted by MercuryOne [1224 posts]
16th October 2011 - 20:06

1 Like

MercuryOne wrote:
Not impressed. Where's on earth is the chain free chain set? Save me loads of time cleaning a chain not to have one - not to mention the all important saving in weight and the opportunity to ride a bike wearing white flares as we'd all like to. Big Grin

Surely it's here already with a Gates Carbon Drive belt? I ride with white flares all the time and have no problems at all. Well, only with getting past the style committee at the front door.

posted by nick_rearden [864 posts]
16th October 2011 - 21:48


What happens when the batteries go flat?
Just asking Wink
Do they last 10,000 years or was that three-in-a-trillion statistic cheating?

posted by arowland [126 posts]
17th October 2011 - 17:06

1 Like