Forget bicycles with gears that you have to change yourself: the first wireless automatic gearbox for a bike does it all for you.
The system, unveiled today, uses your smartphone to calculate the best gear to be in for the current pedalling speed 鈥� then wirelessly shifts up or down.
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It also uses the phone鈥檚 accelerometer to know when to change down in an emergency stop 鈥� so you can pull away afterwards with ease, and will eventually be able to use the phone鈥檚 GPS capability to get the bike into the correct gear for an upcoming incline.
Mechanical automatic gear boxes for bikes already exist 鈥� but they wear out quickly as they鈥檙e based on moving flywheels. The new wireless method activates an electric gearshift that has no such issues 鈥� and thanks to its use of a smartphone can also analyse performance for serious cyclists.
Bluetooth enabled
Developed by Mark Wilson and colleagues at , the wireless bike is based on electric gear shifts made by firms like of Japan. These are normally connected via cable to a lithium battery and gear switches on the handlebars.
鈥淲e鈥檝e cut the cables between the switches and the gears and replaced them with a smart, low energy version of Bluetooth designed for very long battery life,鈥� says CCL鈥檚 Tim Fowler.
In manual mode, Bluetooth on the gear switch communicates with an iPhone in the rider鈥檚 pocket. An app on that phone then relays the rider鈥檚 commands to a modified to receive Bluetooth signals.
In automatic mode, a magnetic sensor on the main crank tells the app your pedalling speed 鈥� known as cadence 鈥� while a wheel sensor tells it your road speed. It then computes the correct gear and beams it to the Shimano mechanism. 鈥淚t鈥檚 not difficult. The link between cadence and speed is the gears,鈥� says Wilson.
Optimum pedalling
For the last two months, CCL has been trying the system on a fixed rolling road. 鈥淥ur tester tells us he never feels like he is in the wrong gear,鈥� says Wilson.
As might be expected, it needs some rider-specific tuning. 鈥淚n set up mode you pedal for a while and then set the maximum and minimum cadence levels either side of where you feel comfortable,鈥� Wilson says.
CCL鈥檚 next step is to integrate the iPhone鈥檚 location sensing into the app 鈥� so it can switch gears ahead of downhill or uphill sections.
Given the cost, Wilson anticipates use by riders who spend a lot on their equipment and want to improve their performance by having their optimum pedalling rate set automatically.
Perfect for triathletes?
Some will worry about the system鈥檚 dependence on Bluetooth, says Joel Natale, head buyer at of London, which runs 50 UK bike shops.
鈥淪himano could have made their system wireless but decided not to. Imagine 200 riders in a peloton are using it. How can you make sure the signals don鈥檛 interact or that somebody else can鈥檛 get control鈥� to stop you changing gear?鈥� he asks.
Natale thinks CCL will face an uphill struggle getting most riders to abandon manual gear changing. 鈥淗owever, there is one group for whom this may make total sense, and that鈥檚 triathlon riders 鈥� who like to ride at constant cadence and power鈥�, he says.
Next, CCL wants to develop a bike version of a car鈥檚 anti-lock braking system (ABS), with the iPhone controlling the bike brakes to prevent a skid. 鈥淎 front wheel lock is generally catastrophic. This may help,鈥� says Wilson.
