Love ‘em or hate ‘em, they’re a very useful tool in maintaining fitness over the winter. When you start shopping around, you will find the two most common types are the mag trainer and the fluid trainer, and here’s a basic rundown on them.
“Mag” refers to the flywheel drive mechanism in the drive head, where the rear tire turns. To get nerdy, it uses ‘eddy current braking’ to supply the resistance – the flywheel is a conductor, and its passage between the magnets causes a braking effect. This resistance is linear, meaning that the amount of resistance the trainer gives is directly proportional to the pedaling forces put into it.
Fluid trainers rely on the friction generated by the passage of a flywheel through a fluid medium (usually silicone, which is thermodynamically neutral: it doesn’t get thinner as temperature increases). This resistance is exponential, which mimics real world riding, where wind resistance exponentially increases depending on your speed.
Which is better? Let’s look at the pros and cons:
Fluid pros
- Better workout, due to the exponential resistance
- Quieter
Fluid cons
- More expensive
- Heavier
Mag pros
- Less expensive
- Lighter
- No possibility of leakage
Mag cons
- Workout is not as good, due to linear resistance
- Louder
- Possible to over-power the trainer if you really stand up on it (Say you’re feeling macho and simulate that last sprint to the finish line – you can cause the flywheel to break free of the magnetic resistance. Think of it like a motorboat: it takes a lot to push through the chop, but once you get up on top, there’s very little holding you back.)
Which is right for you? Hopefully, the above information can help you make that decision.
We carry fluid trainers by CycleOps, and mag trainers by CycleOps and Minoura.
Rich,
bigrich@riderepublic.com
Posted on November 25, 2011
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