A non-contact bicycle trainer that uses magnets to aid propulsion could end the problem of noisy indoor training and the expense of tyre replacement, says its developers. Jim Drury reports.
Bicycle trainers are useful when the weather's bad. But most cause heavy tyre wear and excessive noise that can annoy neighbours and housemates. Canadian triathlete Andrew Buckrell says he has the answer. Buckrell and two colleagues have invented STAC Zero, a fold-up trainer that harnesses magnetic power to create non-contact resistance. SOUNDBITE (English) ANDREW BUCKRELL, STAC ZERO DESIGNER, SAYING: "The way we've made it quiet is by using a non-contact resistance mechanism, using eddy currents. The advantage of magnetism is that it doesn't actually need to be in contact with the surface. So by interacting a conductive surface near a magnet while it's still in the magnetic field actually imparts a resistance to the motion." Two rows of magnets fitted on each side of the rear tyre create the eddy currents, conducted by the spinning aluminium wheel rim. They create resistance of up to 2,000 watts as the wheel moves faster. With no need for the tyre to be in contact with a roller, it won't wear out. And without a bulky resistance unit, the STAC Zero folds up almost flat. SOUNDBITE (English) ANDREW BUCKRELL, STAC ZERO DESIGNER, SAYING: "You can basically slide it under a couch, you can slide it into the back of a car easily for warm-up before races, and this is something we've really been able to leverage just because our unique resistance mechanism is so small." A crowd-funding campaign raised many times the required production costs. The first batch of trainers will ship in September. ....while Buckrell's grateful neighbours won't need to move house to get peace and quiet.