TacX Flux Not Responding to Erg Mode

Message sent to the minions. Wondering if anyone else is experiencing this?

I started using the OS X desktop app about 3 weeks ago on Mac OS Big Sur 11.1 on the new Mac Book Air with the M1 chip. My TacX Flux firmware is on 3.3.40/1.1.6. The bike I am using has a 32T oval front ring, and 11-40 11spd cassette (MTB gearing).

The trainer is not responding correctly to the power targets in ERG mode. I am having to shift to adjust my cadence to hit the targets. So shift to harder gear + increase cadence to hit sub-threshold and above targets, shift down to hit the recovery targets. If I change to level mode, the power is all over the place and I have no idea if I’m even close to hitting the targets.

Before each workout I calibrate the trainer. I’ve gone through all the steps I used to do with iOS app to eliminate interference. The app is connecting to the trainer first, then my Wahoo cadence sensor, then my Tickr Fit HRM.

Next I will try removing the desktop app and installing the iOS app on the computer to see if it does the same thing.

Would appreciate any help.

I have had issues with my ERG, had to make sure I am connected via ANT+ as bluetooth creates issues, I checked that I had calibrated it again after doing a proper 10 minute warm up of the trainer before calibrating and I played around with the gearing options quite a bit rather than what I use with other apps etc.

They guys at Garmin told me to do the following things which I did and now it does seem better, although not quite right and I do still have to change to accommodate flooring wattage issues but that is normal apparently:

Why wont my tacx smart trainer pair with my training app

Tacx Desktop App Connection Troubleshooting

How do I calibrate the FlUX Series Smart Trainer?

Sorry if that is no help at all and the hyperlinks dont work, not sure if they will they dont look quite right. I have found Garmin fairly unhelpful since they have taken over Tacx but I am stuck with the Tacx right now.

Thank you @Gisela_Blackburn. I’ve been doing all those things. The only change in my set up is going from iOS to Mac OS.

There was a file they told me to remove, the minions that is and to use ANT not Bluetooth. I can see if I can find it. I have swapped to Microsoft windows now rather than Mac and it all works fine. It’s a bit odd but I am sure it’s fixable

I have the same problem and bought an ant+ dongle and it works fine. Bluetooth is very hit and miss but ant+ is stable.

Looks like I’d need to buy a USB to USB C hub and an Ant+ USB stick/dongle. No guarantee it will work on the new M1 Air.

They are really cheap like 15 quid so worth it really WORKS fine with ANT… defeats the object of having a Bluetooth equipped bit of kit but needs must at times

Still working with a minion on this.

What I’ve been seeing on my end following the usual steps to eliminate interference from other devices and such.

So on the M1 MacBook Air…

IOS app + BT seems to mostly work
Desktop App + Ant+ seems to work so far
Desktop app + BTLE has lots of signal drops

Glad I found this topic! Have similar issues ERG is kind of working but I need to change gears pretty much constantly. I´m also using Tacx Flux S and macbook air with m1 chip.
Just ordered an ANT+ dongle now and will give it a try.
Did that solve the problem for you?

Yes. My current set up that seems to be working with the desktop app.

Ant+ Dongle on extra long USB cable w USB C adapter:

  • Flux
  • Tickr Fit


  • Wahoo Cadence
  • Sony Speaker

Some workouts with low cadence targets I still need to shift to hit the power targets - I found out from TacX this is expected behavior. I also set my FTP in the TacX app = FF/HM result, and calibrate once a month.

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Thank you for confirming. I should get the ant adapter next week and hope it will improve.

Good luck!

There is also a firmware update the the Flux. Hopefully that helps!

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Need to replace the flux capacitor


That could work, or the old classic reparation tactic…I just kick it! Or more like kickr it…

Got the ANT+ dongle now and gave it a 5 minutes try and yeah this looks like it should be!
Looking forward to the next workout with less gear changing :slight_smile:

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Ok I just did « Half is easy » in ERG mode with ANT+ dongle and it is like day and night!!!
I could do the entire workout in the same gear. With Bluetooth it kind of worked but I had to shift a lot and the experience wasn’t so good.
Now it is just perfect! SUF should really put this in an FAQ somewhere as ERG really works very well and if you are new to indoor training you might not even notice that something is not right…
Not sure if it is a problem with my Tacx/Macbook combination or if it also happens with other combinations.
Thanks everybody for the tips!

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