Roller belt (spring lever) noise


I've ridden about 1000 km with my Tacx Flux S, but had the same noise issue since the beginning (bought in December 2019).

I opened the two plastic covers (even if still under warranty.. nevertheless the shop is not going to reopen soon with what is going on these days) to look inside. The noise always appears at the same angular position of the wheel which hosts the cassette. At this position the roller wich tightens the belt slightly moves. I don't know if it comes from:

  • the belt itself which I believe is slightly deformed.
  • the spring lever wich hosts the roller (I did not disassemble it).

I greased the mechanisme where I can, but it did not reduce the sound. Have you already had similar issues? Is it possible to order a spare belt?

Many thanks!

  • Hello Friend!

    Since I bought mine on October 6 (2020), from the first moment I start pedaling, I notice that knocking noise that occurs in an arithmic way depending on the speed I pedal.

    Although I did not disassemble it because I have an open claim to Garmin Argentina to change the unit for another that does not have that annoying noise level, I suspect that it is the same problem that comes from that belt tension roller.

    It must be a design and construction issue since it happens to everyone, and there are those who do not give importance to those of us who are somewhat more demanding for the money that one spends on this type of article, which is high, and the perceived value The return is that you practically feel cheated for receiving a mediocre product.

    Another problem that I notice in my case, I do not know if you have tried and it would be good if you could pass me your feedback is that it measures power quite badly in my opinion. I have hit tremendous sprints from 0 to 40km/h in a few seconds, and I hold that speed for as many others seconds and the maximum power that I see that it measured does not exceed 350 watts, which seems to me that those values ​​are terrible. Unfortunately I do not have another power meter to compare this values, but I have seen review videos of this Flux S where in accelerations much less violent than the ones I have given it, it marked peaks very much higher that 350 watts!!. And this worries me much more than the annoying noise it makes, since if it does not serve to measure the power properly, this device is completely useless!!

    Well friend, I hope you can give me feedback about it.

    Best regards!

  • Hi there,

    Since I'm also experiencing some noise since last weekend (first use after a couple of months) I made a video since it is more clear that way:

    Does this sound is similar to what you are experiencing?



  • Hi Jan, 

    No. In my case the noise was more of an irregular thumping. Then with the change of the unit that Garmin Argentina made me, I have noticed that the shaft was bent in the defective unit and it was surely the cause of the irregular noise and knocking.

    I have seen the video and from what you show there is a significant problem with the trainer cassette hub, the sprockets should not move as you move them, they must be fixed to the cassette, and the cassette fixed to the roller shaft ... there is something there that not good at all! perhaps that is the root cause of the noise the trainer generates.

    It would be nice if you can take out the sprockets to see how the cassette hub of the trainer is, or it is simply a matter that the sprockets are not well positioned and tight in the cassette.

    I'm sorry I can't be of more help,
    Best regards!


  • Hi Robert,

    Thanks for this extensive reply. Meanwhile I also had a closer look and it seems that the screw that holds the hub in its place came loose (just half a turn left). I never touched this part so that its a bit weird. After fixing it in its place the cassette doesn't move any longer and the noise seems to have magically disappeared! I hope this indeed fixed the issue.