I agree that you'll be able to do intervals longer than 1' on a 700W trainer. Note that it's not really a matter of the resistance of the unit, but more a traction limit for the interface with the tire. I tried an 800W 1' interval on a trainer, and it just kept slipping
Best video for the trainer: Breaking Bad. I'm getting close to the end of season two...
Originally Posted by
canam73
The big difference in feel between fluid and mag is that fluid trainers have progressive resistance, meaning the faster you go the harder it gets, like on the road. With most mag trainers the only way to increase is with a dial control. I say most because Cyclops has a mag model that has a progressive resistance device built in, but I have never tried it.
All of the mag trainers I'm familiar with are progressive resistance. The difference between magnetic resistance and fluid resistance is that mag is linearly progressive, like tires and bearings. Fluid is progressive like, well fluid (air, water, oil) and progresses quadratically. So, on a mag trainer, twice as much speed requires twice as much power. On a fluid trainer, or on the road, twice as much speed requires eight times as much power.
So, one big advantage to a fluid trainer is that it feels a lot more like the road with respect to minor unintentional accelerations, and you also get more normal gearing behavior vs. effort. Many of them also handle their heat better since the fluid is in contact with more of the resistance unit's body, for better conduction to the fins. Lastly, the fluids used do not change viscosity under normal operating temps (even when it's hot enough to sizzle a drop of sweat).