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Home » Why Our Trainers Don't Leak

Why Our Trainers Don't Leak


fluid unit

Fluid Trainers are praised for the their ability to replicate the feel and resistance of an outdoor ride. Kurt's fluid resistance unit is engineered not to leak. The fluid chamber is totally sealed as you can see by this photo.

The roller, driven by your bike's tire, is connected to the impeller inside the sealed fluid chamber by a magnetic coupler. Twelve neodymium rare earth magnets, 6 per side, create a virtual drive shaft to spin the impeller inside the sealed fluid chamber.

Although the drive shaft has two parts, the magnetic coupler links the two parts and it spins as a single unit. The magnetic field is so strong; it can withstand the torque of suddenly accelerating the roller from 0 to 50 MPH with an electric motor. These magnets are not used for resistance, but only to couple motion across the leak-free barrier. Because there is no moving or rotating part penetrating the sealed fluid chamber, it will not leak. Unlike competitive units, which are only warranted for manufactures defects, Kurt provide a rock solid Unconditional Lifetime Warranty.



Why other trainers
can leak:

All other fluid based trainers including those made by Cycle-Ops, Trek, Blackburn and Elite use a drive shaft and rubber seals to spin the impeller in the fluid chamber. In our opinion this is an inferior design, doomed for failure. It is not a matter of "IF" the resistance unit will leak, but "WHEN" the resistance unit will leak. The more you use the trainer, the faster it will break or leak. A Cycle-Ops is pictured left.

As you can see, a drive shaft spins the impeller in the fluid chamber. Under extreme load, this drive shaft spins at 8,000 RPMs and the core temperature can reach 400 degrees F. A simple rubber "O- ring" with a backer spring is the only thing that keeps the fluid from leaking out of the resistance unit.

Using Crank Armstrong, Kurt Engineers can break a competitive trainer in several hours. Feedback from bike dealers confirmed that leaking fluid units are a major issue with " other" trainers. We continue to perform destructive testing on the Kinetic trainer. Running at an average of 25 MPH, one resistance unit that we have tested has logged over 40,000 miles at up to 50 MPH with no leaks or breakdowns. The engineers believe it would run over 100,000 miles without a problem.