Tacx Flux 2 issues

Is it possible to undo the Zwift challenges I’ve unlocked as a consequence of this fault ??


No as far as I am aware of.

According to Zwift the 2000 watt spikes were a tacx flux 2 firmware issue. But my last 3 rides were without the spikes, the Tacx Flux 2 still running FW 1.09 and i think (which means i’m not sure) after a update from Zwift. Happy that the spikes are gone. Don 't mind where it went wrong anyhow.

Ever since I learnt what not to do (stop pedaling…), I havn’t seen the 2KW. Granted, Zwift can address the issue (not “fix”), by removing excessive wattage (don’t know if they do).

Still waiting for the new F/W…

I’ve just got a flux 2 and there is a spanner coming up on my page where the cadence is and keeps asking me to Pedal up to 37kph and then stop each week to keep my cadence up to date but keeps saying failed, is anyone else having this problem.

Hi Mark,

The spanner is Zwifts calibration option. It doesn’t work with the Flux 2 at the moment. You can ignore it and use the Tacx app to calibrate your Flux 2. There’s another thread about this here

Well, the new F/W is has finally arrived… (actually, a couple of weeks ago.) No more 2KW… :frowning_face:

Note, however, that whenever the flywheel is spinning faster than the pedals, power output drops to 0. To me, this is the result of the Flux2 only estimating the power, and once there is no tension between the pedals and the flywheel, the device - unable to estimate - still needs to output some value - hence the “0”.

That sound about right, if the flywheel rotate faster then you are no producing any power thus it should read Zero. even if it had strain gauges and measured torque it would read Zero.

Hi, i still have same problem with 2KW peak on classic(not ergo) mod. What number of yor firmware?

i don’t belive it’s only the firmware.
A friend of mine bought its Flux 2 a week ago and struggles with that peaks. I bought my Flux 2 two weeks ago and i never had that issue while cycling for 9h and 250km.
I have a 51xxx serial number, she has a 58xxx serial number.
Both we have the firmware 1.1.2 and com-firmware 3.3.40 so i don’t think it’s software related

what is a difference in the setup is that i use the sigma Duo cadence sensor. Maybe that is the point why it works for me

i have all problems: power output spikes at zero cadence, inaccurate cadence and resistance control stopping after stopping pedaling
what FW i have to install ?

serial #87xxxxxxx

None of the previous issues ever since the update.

i have the same FW version and still all problems …

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Same for me!! Any news? It’s frustrating and pissed me off!! Can’t finish a workout and never had this issue with my old Elite Direto. What should i do?


Forgot to mention built-in cadence sensor is mostly useless as well… (for me.) I have resorted to using an independent cadence sensor attached to the crank arm.

Unfortunately, and although the service here is decent (possibly an understatement…) I don’t have spare time to invest in the trainer. “Good enough” is good enough…

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Hi I bought a Flux 2 about 2 months back - and been using it regularly with zwift no issues - however I needed to reboot my computer a few days ago, and since the i’ve had some problems with the connections - it connect fine - but suddenly it drops out and just shows “no signal” - this is pretty bum during workouts.

Any ideas? - i’m pretty sure it has nothing to do with the reboot - which was necessary due to loading-times.

Are you using ANT+ or BLE? Win10?

Just wondering… I had some strange similar (depending on configuration…) occurrences recently.

I use my Ant+ dongle, and chooses the ant+ device in zwift - but it is serching for both - can I avoid it searching for BLE

And yes it is win10

I had complete ANT+ disconnect a couple of times on my fully updated Win10. Could not make it see any ANT+ device even after re-plugging the dongle (lost my other dongle…), while still seeing all sensor on my '935 using ANT+. Switching to BT, I was able to continue riding.

Yesterday’s ride was uneventful…

Don’t think it’s a Flux2 issue.