I am running Xert through my Garmin 530 on Zwift. Pretty cool. The Xert workouts are using ERG mode. I get discrepancies between Garmin distance and Zwift distance that are significant (over 10%). I assume the differences are largely elevation based, which Zwift uses but Garmin wouldn’t. I suppose there could be some power curve differences too. Am I missing anything else? Why would you want an ERG workout to incorporate anything beyond power when calculating distance? It creates training log discrepancies and also causes me to limit my courses to stay as flat as possible. Could Zwift create an ignore elevation toggle for ERG mode? Should they?
Welcome to the forum.
You are correct your garmin and Zwift won’t match, the Garmin don’t know if you are going up or down or if you are in a group drafting. Or even your in game bike MTB or TT or Road.
If you do a workout on the Road you also get distance, so you ride a specific route in Zwift and that give you distance.