Power fluctuates during ERG workout

Hi All,

I am using a Tacx Flux since a few week and since yesterday I am experiencing some power drop downs during a workout. For example: I should bike 3 minutes at 200 watt but it keeps going down to 150 for 1 second and then bounce up again.

My set up is a MacBook Air for the Zwift screen.
Garmin 530 to register my activity in Garmin connect
iPhone 11 Pro with bluetooth wireless earphones.

After the power fluctuations I tried different settings,
Once with my phone and without bluetooth earphones,
once with my phone and without the garmin
once with only my phone and same goes for using my MacBook instead of the phone.
I deleted the swift app on my phone and laptop. updated every device to the newest software and calibrated the Tacx multiple times. nothing really seemed to work.

After 2 hours by some miracle the original set up worked again but today I found the same problem.
Does anyone have an idea of what can cause this to happen?

What connection are you using between Tacx Flux and Macbook Air?
Ant+ via dongle
Bridged Bluetooth via companion app?

I’d recommend, if you haven’t tried yet, to use Bridged Bluetooth via companion app?

I am using bluetooth.
I have tried using the companion app as a bridge but this seemed to only make it worse by giving me no watts.

I’m having the same issue! Only started in last 2 days

I contacted the Zwift support team. Will let you know when I got a solution


I also had this problem starting this morning. Power drops were consistent in their timings, approx every 30 seconds. I checked Zwiftilizer and no drop out issues to explain this. I’m running ANT+ on Windows 10

For me there were also not drop outs on zwiftalizer. Unfortunately I didn’t here back from their support team yet