Power meter reading and Zwift watts difference


I recently buy a 4iiii precision power meter, when I am in zwift the power readings are from power meter are usualy 50-60W lower, then power from the smart trainer.

Any advice? I am using Tacx Genius Smart Power Meter.


Thank you

Probably the power of your trainer is off and broadcasting too high, sorry. 

Hi Dan,

I experienced something very much the same when I upgraded my bike to a power2max power meter. Depending on the power I’m actually pushing the readings from the power meter are usually 20-30 watts lower than what my Tacx Vortex shows me. Other than that the Vortex needs to warm up and the warmer it gets, the lower the power readings are and also the resistance seems to go down a bit. I checked tyre pressure and calibrated the Vortex with the Tacx App but there’s still a difference in power data. I think if you want to be sure about the power data you should use your power meter as the power source, which is what I did.