Originally Posted by
MinnMan
Thanks for the input folks. I may go for it.
But I might be more confused about ERG mode than I was before I read your posts.
Riding Zwift on a smart trainer in non-ERG mode, you will feel increased/decreased resistance in the pedals as the grade in the virtual world changes. It mimics the real world in that regard moderately well (except for being able to coast on moderate downgrades). The amount of power (measured in W/kg) you exert changes your speed in the virtual world.
ERG mode is based on just watts. In a programmed workout, a segment will be X duration at Y watts. Let's say the work segment of your chosen program is 30sec @ 500W. When you get to the start of that segment, you will need to put that many watts into the pedals to keep the bike moving in the virtual world. Cadence is irrelevant. You can do 500W at 100rpm or 50rpm, as long as it's 500W. Your cadence may even vary during the segment and the computer will adapt to it. (Note - Some programmed workouts have a recommended cadence for each segment). When that segment is over, there will be a new demand for X duration @ Y watts. Once you experience it, it will make total sense.