Inaccurate speed

 I’m new to Zwift and can’t figure out why the speed is so inaccurate. I read previous posts and I know it won’t match my Garmin, but that’s not the issue. If I"m doing a 10min TT @ 130W, my speed can be anywhere from 8kmph to 40kmph yet my watts are consistent. I have a Vortex smart trainer and I don’t have an ANT toggle for my ipad mini. Could this be the issue?

At the same wattage, your speed should vary when the Zwift in-game terrain is uphill, downhill, etc.

Thank you. I know there is elevation gain/loss on the "routes? , but I’m only riding programmed workouts ex: 4week FTP booster. I don’t see any elevation noted as I ride. What am I missing?


You’re still in Zwiftland as you’re doing workouts, so there is still terrain. Just like doing watts outside where the road goes up and down, speed will vary.

Got ya! Thank you so much!