Originally Posted by anotherbrian

The add-on to the Kurt trainers that provides wattage (inRide?) has a spindown calibration process for getting accurate wattage -- or I assume wattage that is consistent with their published table. I bought my KK before the inRide was available, so I confirmed/adjusted the power curve for mine by being very consistent on tire air pressure, and consistently cranking the roller down the same number of turns (exactly 2.5 turns from the tire just beginning to brush the roller), and then measuring the required speeds for the wattages I was interested in.

My measured wattages didn't match the Kurt curve, though it wasn't far off (and for me ultimately doesn't matter, since I end up doing a time crunched'ish approach of all-out/tempo/cool down and don't worry too much about the exact watts). If I do an FTP test on the trainer, I swap a Powertap wheel onto the bike I ride on the trainer.

Before TrainerRoad became popular, the only trainer I found that had published power curves was the Kurt's, and that was the reason I bought one. The OP asked about what wattage correlated to his effort, and from the charts, it looks to be a huge difference in effort for the same speed of one brand/type of trainer to the next (though the Cyclops chart didn't come from the mfg). The difference shouldn't be surprising, and just reinforces that speed (and resulting distance) are meaningless on a trainer, at least until you can get the power curve chart, and even then you may need to be suspect of it.