Kurt Manufacturing didn’t plan to get into the fitness equipment business. The Brooklyn Center–based company is a longtime maker of precision parts—crankcases, bearing caps, gearbox assemblies—for customers including GM, Lockheed Martin, and Boeing.

Several years ago, Wisconsin-based Cirrus Cycling Group asked Kurt to manufacturer its Cycle-Ops cycling trainers. A cycling trainer hooks onto and suspends the back wheel of a bicycle, letting users ride indoors. Kurt invested heavily in machining and tooling to manufacture the trainers for Cirrus, but the Wisconsin company went bankrupt before the products could go to market.

Faced with significant impending losses, Kurt decided to get into the trainer market itself, leading to the 2000 launch of its sports business division, Kinetic Cycling. (Cirrus’s Cycle-Ops, business meanwhile, was bought by another company, and has become one of Kinetic’s top competitors.)

Rather than simply sell the original Cycle-Ops trainers—which, like most other trainers, had a tendency to leak the internal fluid that creates resistance against the rear wheel—Kinetic refined its newfound product. These days, Kinetic—whose manufacturing facility is in Jordan—is a leader among makers of bike trainers, thanks largely to its promise that its products are leakproof.

The secret, according to the company, is the fact that there are no moving parts penetrating the sealed fluid chamber. The tire-driven roller on a Kinetic trainer is connected by a magnetic coupler to an impeller. The impeller is a rotating piece of metal inside the fluid chamber that forces the fluid outward from the center of rotation. Six magnets on either side of the chamber spin the impeller. There is no spinning drive shaft from the roller into the chamber, as on most other trainers.

“The idea to re-engineer the trainers came from the bosses at Kurt,” says Paul Carlsen, the division manager for Kinetic. “But our in-house engineers did all the design work on it, and had the ideas on how to improve the product.”

Of its four trainers, Kinetic’s original Road Machine accounts for about 80 percent of its sales. But the company is developing new products, including a trainer that can be used as a generator to power a home. It recently introduced a trainer that rocks and tips like a bike would during an off-road ride.

Kinetic Cycle’s sales have averaged between 30 and 40 percent growth since it was formed eight years ago, resulting in nearly doubled revenue over each biennium. Carlsen says Kinetic’s primary market is cycling enthusiasts, with about 85 percent of its sales going toward that segment. But the remainder of its market, consisting of more general fitness types, is growing.

“Fitness is a market where bike trainers really haven’t made much of an impact yet,” he says. “It’s just a matter of educating them and letting them know we’re there. Instead of spending a couple thousand dollars on a stationary bike, they can buy a trainer for a few hundred bucks and use the bike they have.”