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Tacx NEO Bike speed difference between app and fenix 6 pro

Co
over 1 year ago

Hi,

Also posted this question in the Tacx NEO Bike thread, but so far no luck/response.

I noticed a strange difference between the speed metric shown on the Tacx App and the Fenix 6 pro. While I do a workout and tracking both on the app and Fenix 6 pro it looks like most metric are the same, like RPM, Watt, BPM (via Garmin HRM)… but for some reason the speed (km/h) is 1,5-2,5 lower on the Fenix!?

Fenix is connected via ant+, so my assumption is that it will receive the same data as the Tacx app…

Anyone a suggestion on the root cause?

thanx, Co

  • 0 over 1 year ago

    At a guess the app is calculating speed from power and other data (like gradient, rider weight) whereas the watch simply displays the speed/distance from the speed sensor in the trainer and, for that to be "accurate", you need the correct calibration of "wheel circumference" for the speed sensor in the watch.

    But there is no reason for the numbers to match because they represent completely different things. If you use erg mode for training then all bets are off, because "wheel" speed will bear no relation to power output or simulated speed in the app.

    p.s. I say "at a guess", because I don't know how you are using the app - workouts, sim mode etc. and I use Zwift with my Neo 2 rather than the Tacx app, but if my guess is correct then everything I say stands.

  • 0 over 1 year ago in reply to eezytiger

    Thanks Eezytiger,

    Understand your comment, but not sure how I can solve it. First I think the connection with the bike should be changed, currently my Fenix is connected as Trainer and not as a power sensor. i see no options to adjust wheel sizes or anything.

    Second, I have the Tacx Neo bike, for which I can’t find any wheel measure (it has a fly wheel).

    Will do some further research, but any thoughts are welcome. 

    regards, Co

  • 0 over 1 year ago in reply to Co

    The TRAINER pairing is for control of the trainer by the watch.

    You should pair power and speed/cadence from the trainer to the watch as well. When you pair the speed sensor you can scroll to the option for wheel circumference. For my Neo 2 I use 2133mm. I guess the bike might be the same, but I have no idea.