Some trainers are louder than others. We took three trainers—Stac Zero, Kurt Kinetic Rock and Roll – Smart Control and Blackburn Tech Mag 5—and placed a decibel meter–app close by.
We weren’t surprised by some of the results. The Stac Zero, from Waterloo, Ont., didn’t make a sound because it doesn’t have any moving parts. It has a a caliper with a magnet on each end that you position around the brake track of your aluminum back wheel. The magnets create swirling electric fields, called eddy currents, which form within a conductor, in this case, the aluminum rim or brake track of your wheel. When the wheel spins through this magnetic field, there’s resistance. The noise we recorded was simply the sound of the bike, roughly 72 dB. You may notice a fairly high maximum decibel reading during the Stac Zero test, in the low 90s. That reading came after the rider momentarily stopped pedalling and the freehub kicked in. There’s one loud freehub on the bike.
Blackburn Tech Mag 5 was the loudest of the trio. It’s a magnetic-resistance trainer, a type that’s known for producing a bit of volume.
The biggest surprise was the reading we got from the Kurt Kinetic Rock and Roll with the company’s new Smart Control system, a Bluetooth Smart resistance unit that works with Kurt Kinetic’s training app. The Rock and Roll was just a quiet at the Stac Zero. We had assumed that the moving parts of the Rock and Roll would produce some noise. If they did, the noise of the bike overshadowed any noise made by the trainer. It’s a bit ironic: the trainer that takes its name from a style of music best enjoyed with lots of decibels produces a low amount of them. Rock on…quietly.