Power does not remain stable

Could you please advise me how to solve a problem I am having during training ?
During the training (Ergo mode of course)the Watt do not remain stable at the level of the exercise but reduce by a 10% to 20% for a while and then return back to the level of the exercise and again down and again back……
I reinstalled the application, switched off/on my Tacx Flux trainer, calibrated it but the problem insists.
Any advise how to settle ?

how’s your cadence? If you’re not keeping a steady cadence and are riding reactively it could be causing the fluctuating watts.


It sounds like you’re probably experiencing something common for folks who come to a Tacx trainer from another platform - ex. Wahoo

A Tacx trainer doesn’t smooth out your numbers like other trainers do. When in Erg, it shows you the actual output, not a smoothed average. Try just picking a cadence and sitting at it to see if it settles in, but don’t expect it to sit at one number, that’s not how the human body works. Expect some variation, but just sit at the same steady cadence and see if it doesn’t settle in. What most new Tacx users do is what I call “chase the number”, so they see, for example, that they’re supposed to do 200 watts, but it says they’re at 225, so they slow the cadence, but then it says 175, so they speed up the cadence, and end up in an endless cycle of varying cadence to “chase the number”. Instead, pick a cadence, say 90, and sit there, and see what happens. It should quickly settle in and give you 200, 195, 205, 201, 206, 197, etc…which will average to 200. That’s how the human body works. In essence, those other trainers are “lying to make the lines look pretty”. Hope that makes sense and helps.

Thank you for your response.
I have a steady cadence. Is not an issue of cadence.

Thank you very much but I am afraid that this is not the issue.
Is not an issue of a light fluctuation but I feel immediately to the pedals that the watts from 200 (under the same cadence) go down to 180 and I feel it immediately to the resistance.
I could describe it in a better way that the resistance comes to be lower resulting the lower watts. Hence the problem starts from the resistance.
Also this is not constant. For a period of 6 months might work without problem but suddenly the problems start….
Thank you again

1 Like

Sorry! Troubleshooting is a pain.

Did you try checking to see if something else is trying to steal the signal from the trainer? The best way to do that is to literally turn off every device that has ever controlled the trainer and only turn on the one you want to use to train.

Sometimes if I have been letting Zwift control and then TR control, or the Tacx App and then TR, or a combination of connecting to AppleTV, phone, laptop, etc., they will briefly swap control in the middle of a ride and make things feel uneven. Shutting down every device and just turning on the one is worth a try.

I appreciate your efforts
Bells are ringing!!!
Thank you so much.

1 Like