I recently picked up a powertap and have done a fair bit of riding around and a few races now with it on, so I've started to get familiar with some of the numbers. I would like to figure out what my functional threshold power (FTP) is and would like to know which methods are more accurate.
I know a 40km time trial is sort of the gold standard, but I find these so mentally tough that it's nearly impossible for me to give an honest effort outside of a race situation.
Nothing is going to be easy, I imagine as any interpolated ways of doing this will probably require maximum effort for a certain amount of time, but I'm hoping there is a reasonably accurate method that is easier mentally and physically.