Tacx NEO 2 power accuracy

Hi guys,

My Tacx NEO 2 shows lower power compared to Assioma duo power meter. I tested my FTP on Zwift, and the results were as below.

Tacx NEO 2: 190W

Assioma duo: 220W

It seems Tacx NEO 2 outputs 10% lower power constantly. Is there any way to fix this?

  • Start a formal complaints procedure or email the CEO. 8% is not less than 1%.

  • Hi any updates, I have the same issue and also using Assioma Duo PM and again 5-10% difference in the reading. 


  • Garmin just kept replying to emails with the same standard stuff. I eventually got sent a replacement by them and it had the same issue. They wanted me to do all the tests again and kept replying that the power difference (which varied between 8-15%) was in tolerance. Customer services would say “techies said X” it was an utter waste of my valuable time. Multiple phone calls where I’d get somewhere with explaining, and then get cut off as well. 
    Eventually I went to Wiggle and they said leave it with them. They gave me my money back even though by this point I had a Neo 2 rather than the Neo 1. Wiggle were awesome. I spent the money on a wahoo. Problem solved.

  • Same problem for my , Tacx NEO 2 outputs -+ 10 % lower power than my Assioma DUO 

    FTP power from Garmin Edge 1030+ with Assioma DUO = 200 Watts

    FTP power from Garmin Edge 1030+ with NEO 2 T =-+ 170 Watts

  • Did you get a response from Garmin? I have the same issue where the variance between my Stages and Neo 2t was between 9 to 11% across all power ranges.  The Neo is indeed reading lower consistently I did touch base with Tacx support who passed me onto Garmin support and all I got back was the Tacx is one of he most accurate  trainers out there. They would not even ask me to send in the fit files when I suggested I had verification. with duo recording on numerous rides.  Not sure what to do now. 

  • Anyone notice difference between ERG and Freeride powers in Zwift.  I have compared my power from Neo2 (Zwift recording BT) to my Quarq Dzero (530 recording ANT+).  In free ride (including races and events like Tour de Zwift) accuracy varies to 0-1%. Love it!  But in ERG on any interval workout (including event workouts) my Neo2 is running 5-6% higher than my quarq.  I have done a linearity test.  Seems to be pretty consistent from gears 1 to say 13 or 14 in reading 5-6% low.  But starts to close the gap of percent error and match at the higher flywheel speed of being in gear 22.  Problem with that is the power line is not smooth as the trainer trying to hold power average and most say to ride in the small front ring...

    firmware 0.0.38

  • I have too Tacx Neo 2T, and the neo reading 3-8% lower than my 4iiii power meter. Calibrated everytime my 4iiii PM, and the results are the same.

    "Neo is measuring it at the cassette, you should expect about 5% power loss from the drive train, depending on how much power you're putting out."

    It is good to take this into account!