University team develop wireless braking system for bikes

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!