Originally Posted by
gregf83
To get a better estimate of your FTP find a hill that takes 20-30 min to climb and ride it as hard as you can. The steeper the hill the better. kreuzotter.de has a decent calculator where you plug in your numbers and a power estimate will be provided.
On the kickr there is the standard spin-down which it sounds like you've tried. They also have a factory spin-down that can be used on occasion for a, supposedly, more accurate calibration. Wahoo can provide instructions for the factory spin-down.
I believe this adjusts the inductive braking force.