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Tacx Flux ERG performance

cossyrushcossyrush Posts: 36
Got myself a Tacx Flux a few months ago, not had a turbo trainer before. I’ve only just got round to using it properly.
Anyway I was a little underwhelmed by the performance in ERG mode, I wasn’t sure if it was working correctly or if was just expecting too much from it.
It was also getting a little noisy so today I took it back and have a new replacement under warranty.

Before I set up the new one I want to check how the ERG mode should work on this trainer.
What I found was that at low power, say 150W, the trainer wouldn’t back off the resistance enough.
I had to either significantly drop my cadence or to change up the block.
ERG was working ok (ish) at higher powers, by this I mean I could feel the resistance changing, but I wouldn’t say it was particularly good.
I’m using 39T chainring and mid way down the cassette at the back.
It’s almost as if the Flux has a really narrow ERG window.

I rode my friends Kickr Core, it was really quiet and the ERG worked exactly as I expected, with wide variation of power without having to adjust cadence or gearing.
Basically the Core performed exactly I expected a smart trainer should.

Anyone using a Flux?
Does the ERG work over a wide range?
From say 150 to 400w without needing to change gear?
Do you think my first one was faulty, or is this just the way the Flux works?

If it is then I’ll be tempted to try to return it for a refund (technically I’m outside of the 30day return window) and spend the extra to get a Kickr Core.

Posts

  • StillGoingStillGoing Posts: 5,207
    For most smart trainers it is best to use the inner ring and centre of the block. If you're going to change trainers, I'd go for the Neo 1 with the deals to be had.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • In ERG mode, I believe it is common for the mode to work over a certain cadence range in a certain gear. For example, I think the Direto will cover approx 80-400W in 34/18 gear with a cadence in the 80-95rpm ballpark.
    ================
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  • zeeezeee Posts: 103
    I have been using the flux for a few months. One of my sessions consists of intervals from 125, 145 and 215. I am in the inner ring and 4 cogs down on the cassette. I haven't changed gear since before Christmas so erg mode works as should for me. I keep my cadence between 80-90 and the trainer adjusts accordingly. Mt trainer is slightly noisy to start but after a few minutes it is virtually silent.
  • Thanks Zeee, that’s exactly what I wanted to know.
    Sounds like my first one was faulty.
    Just for clarity Can I ask what size front chainring, and which rear cassettes (11-28 for example)
    The way your trainer is working is exactly as I was expecting.
  • dannbodgedannbodge Posts: 947
    Sounds like your hitting the trainer's floor.
    A lot of tsmart trainers have a lower wattage limit due to the flywheel needing a certain power to spin over.
  • zeeezeee Posts: 103
    cossyrush wrote:
    Thanks Zeee, that’s exactly what I wanted to know.
    Sounds like my first one was faulty.
    Just for clarity Can I ask what size front chainring, and which rear cassettes (11-28 for example)
    The way your trainer is working is exactly as I was expecting.

    On my turbo bike I run 50/34 and 11-28. Currently sat in 34 and 21 and has been for a few weeks. I think around 120 is the bottom of the range for the flux erg mode. But you don't really do much below that level anyway.
  • Great, thanks again Zeee.
    I won’t be going lower than around 140W.
    Sounds like you are happy with your Flux.
    Hopefully I will be too, once I’ve tested the replacement I’ve got.
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