For reasons I won't bore you with I have been confined to the garage for my training for the last six-seven months.

I have been using my road bike on a Cycleops magnetto classic (see: Here)

What I was wondering is if anyone had a feel for like for like gear resistivness compared to the road and air.

i.e. in the same gear this trainer is like riding on flat, 2% uphill, 1% downhill etc

I know its a pretty theoretical topic, I am just training for a centuary and will only have a few months road time before hand so trying to guage where I am.


  • Not sure what you are doing to keep yourself interested on the turbo sessions but I would have a look at sufferfest, it may help you train for your century thesufferfest.com
    – robthewolf
    Apr 21, 2013 at 11:31

1 Answer 1


This Cycleops document appears to show the speed-power curve for the Magneto trainer. A few comments: first, the actual power demanded will depend on the pressure between the tire and roller, so you will want to make sure that is consistent between trainer sessions. Second, note that the power increases roughly linearly with speed, so if you double your speed the power also doubles. This is typical for magnetic trainers, and you may want to know that in the real world on real roads, power increases roughly with the cube of speed, so if you double your speed, the power increases by a factor of eight. Lastly, there are online "trainer" services (including www.trainerroad.com) which claim to have calibrated a wide range of trainers to estimate the speed-power relationship. I have no first-hand knowledge of these services, but typically one installs an ANT+ speed sensor on the rear wheel of the bike, mount the bike onto one of the listed trainers, insert an ANT+ dongle into a nearby computer, and connect to the online service.

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