The State Of The Tacx Flux Smart Trainer And What Is Tacx Doing About It

UPDATE OCTOBER 30th, 2017: Flux fixed the issue with its faulty units and here is my full review of the Tacx Flux

The Tacx Flux was one smart trainer I was looking forward to testing. When Tacx announced the Flux as a direct-drive trainer with a price point that is few hundred dollars cheaper than any other direct drive trainer on the market, it had a real potential to take a substantial market share from the KICKR and possibly their own Tacx NEO.

After few delays in production, Tacx didn’t start shipping the Flux until late November. I received mine after Christmas, which I purchased to test for the purpose of a review on this site.

The testing didn’t go as planned and the unit failed around the 50-minute mark. If you read any of my reviews, I like to put the trainers under real training scenarios to see how they perform under real stress and give you my honest opinion. I am not paid by any of these companies and don’t intend to get paid by any of them to continue to provide you with my honest opinion.

I wasn’t sure what happened with my unit. I was pushing through some sweet spot intervals, and I started to notice a belt burning smell. A minute later, the trainer lost all resistance and I could tell something went wrong with the belts inside the trainer.


Afte doing some research and talking to Tacx, it turned out the transmission belt can jump out and become misaligned due to the Flux chassis flexing according to Tacx. They are aware of the issue and they are addressing it with their customers.

Another issue some might experience was due to too much tension on the EDCO freewheel hub damaging the connector between the large metal pulley wheel and EDCO body as you see in this video produced by Shane Miller:

According to Tacx, only 1.7% of units might have this issue. That was due to quality problems in their factory during the assembly process. Flux comes with a 2-year warranty and Tacx is committed to working with any customer with the unit and help fix this issue.

I am a little unsure about the 1.7% figure. That number seems a bit low. I’ve been hearing from many users with similar problems, and I think that number is much higher than the 1.7% Tacx is claiming. A Facebook group was even created to discuss the issues with the Tacx Flux.

Also, Tacx claims the issue was with earlier units. The unit I received wasn’t out of their first batch or maybe it was. All I know it was suppose to get it late November, but was delayed to end of December.

Tacx had a similar issue during the assembly of the Tacx NEO. That issue was quickly resolved by Tacx. The NEO is currently my main trainer and I have been very happy with it.


For now, I will wait for Tacx to address these issues with the Flux before I run another test. In the meantime, if you already bought the Flux and have been riding it for a while and didn’t experience any issues, then consider yourself one of the few lucky ones that received a good unit. I also would love to hear from you. You can contact me directly, or post in the comment section below.

If you have been waiting for the Flux, then I would recommend looking into a different trainer. The CycleOps Magnus or Wahoo KICKR Snap are two very solid wheel-on trainers that you will be very happy with and priced lower than the Flux. But if you want to enjoy the experience of a direct-drive trainer, then the Wahoo KICKR or CycleOps Hammer are two very solid trainers but come with a higher price than the Flux.


I am currently monitoring the issue and in communication with Tacx. I will provide more updates once I hear more.

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  • I have had my unit for about 6 weeks. Mechanically it works well but I have had issues using it with TrainerRoad. The Erg function only works intermittently, and within each workout, sometimes kicks on for one interval then off for the next 2. Other times, the power or cadence numbers bounce around significantly. I have been in touch with TrainerRoad and Tacx and they are looking into it.

    • Thanks John for the information! Glad to hear your Flux been working well for you. I did notice that as well with TrainerRoad but mine ended up breaking unfortunately so I had a bigger problem to look into. Please keep us updated with the TrainerRoad issue if you don’t mind.

      • My Erg function remains variable with the power wattage still bouncing around over a range of about 30 watts. I’ve noticed the same problem while using the Tacx training app on my iPhone as well. I contacted Tacx and they’re saying my Trainer needs to be replaced. Very frustrating.

        • Hi John, i have been reporting the same to Tacx … apparently there is nothing they can do; that is what it is … really; it took me a month of back and forth over email + lining issues one-after-the-other before they eventually decided to send a replacement unit. That i will be picking up tomorrow … i am as much excited as i dread the moment i will realize i can not pick up my training where i left it on Nov,3rd …the D-Day i bought the Flux to replace my 1 year *ULTRA* reliable Vortex which i regret so dearly now …

  • Purchased a Flux a week ago and it was apparent there was something wrong with it fresh out of the box.
    Grating sound and a burning smell, with the freewheel grinding to a sudden halt every revolution.
    Contacted Tacx, but no reply. What’re they going to say anyhow, “yes you have one of the faulty ones”?
    Will be sending it back for a refund.

  • Purchased a Flux in September. Everything was fine but last week weird issue occurs. Power/status red LED light continuously flashes. Tacx utility app connects the trainer immediatelly but it´s impossible to disconnect it. Any advice? Thank you Petr/Czech Rep.

      • Hi, Yes I tried it many times. I discovered that it is (maybe) caused by the temperature sensor inside the trainer. I have the trainer stored in the cold (but dry) room. The manufacturer is developing an update for that issue.

        • Your issue is related to cold weather, you can either keep pedalling for 5 mins to warm it up or email tacx support and they are currently testing a firmware update which resolved the issue on my unit. How ever mines started making some odd noises!