Originally Posted by
plantrob
Even on hills it's not all that useful. I guess it is probably OK to compare your own rides, but forget about comparing your power output to that of others. And of course it requires that you keep your weight up to date in your Strava profile.
No, it's not even useful on hills. I can mess it up by surging the steeps and recovering slightly on the shallows. The time goes down, power (on my PowerTap) stays flat, and Strava's estimate goes up.
Might be useful on a windless day with a very steady effort.