First Look: Tacx Announces New Flux 2 Smart Trainer


While much of the attention in the Tacx booth today at Eurobike was on the soon to ship Tacx Neo Smart Bike, there was also a lonely trainer swirling around quietly in the corner – the new Tacx Flux 2 Smart.  This unit squeaked just in time to the show to be able to be put up on a pedestal (literally) – but wasn’t yet in riding condition.

Still, it’s worthwhile taking a look at the specs and seeing where they stand compared to the other mid-range entrants that are on the scene.  After all, it was just a few weeks ago that Tacx reduced the price of the original Tacx Flux from $899 down to $799.  Meanwhile, this new Flux slots right in place price-wise where the original unit left off – resuming the $899 spot.  A spot that is mirrored by Wahoo’s latest entrant today, the KICKR CORE as well as Elite’s Direto trainer – all of which are direct drive trainers.

The Tech Details:


As I said up above, there wasn’t an opportunity to ride the unit yet – so the jury is still out on that.  And even that aside, the reality is this is a very minor evolutionary update of the Tacx Flux trainer, rather than some huge shift.  And that makes sense given how deep the Tacx lineup is in terms of numerous models (I’d argue, probably too many models – almost like Elite was years ago).  They’re having to be careful to not step on the toes of other units.

In any event, the changes here are actually pretty good – even if they are small in number.  The following items have been changed from the original Flux Smart:

– Dramatically decreased speed you can maintain 15% grade at from 50KPH down to 10KPH (more on this in a second)
– Changed simulated flywheel mass from 24.7KG to 32.1KG (this impacts road like feel)
– Lowered the trainer resistance floor (ideal for smaller folks trying to do intervals with lower wattages)
– Increased sprint support up to 2,000w vs the 1,500w
– Now including thru-axle adapters in the box (versus separate as accessory)
– Increased long cage derailleur support
– Pile of internal improvements like tweaking tension roller which slightly impacts feel and accuracy during sprints

Some of these aren’t necessarily box-listed stats like change to accuracy (+/- less than 3% still the same), nor crazy things like 24% incline.  But in reality, the changes made here are actually probably more important.

Take for example the speed change for maintaining 15% grade. That’s actually much bigger than folks realize.  See, the deep dark secret with trainers is twofold.  Part of it is that Zwift by default halves the trainer difficulty level.  So when you see 8% grade, its actually only giving you 4% grade and then virtually slowing your speed down.

Why does it do this?  That’s the second part: Most trainers aren’t really designed to handle very low speeds at high gradients.  So the mid-range trainers and lower end trainers especially suffer here, and can’t hold the inclines they say at the lower speeds.  For example, the Flux 1 can technically hold 15% grade…but only if you were going 50KPH. Which of course nobody is doing.

So bringing that entire range down to 10KPH is a massive shift. That’s a realistic value, and thus you can realistically make that work at 100% trainer difficulty (versus the default halved value on Zwift).


Likewise, the shift to the trainer resistance floor is useful for smaller athletes that may have lower FTP values.  Meaning, they’re putting out less wattages.  Previously they’d have to find a gearing combination that allowed them to go to lower watts during the recovery portion of intervals.  But sometimes doing that meant that the trainers didn’t react as fast.  So it was a double-edged sword.  This lowers that ‘resistance floor’ as it’s known significantly.

In talking with Tacx they showed charts of how they’re starting to re-architect their trainers a bit to focus more on the specific zones people are actually riding in, rather than going for mythical 24% at 50KPH type specs.  I’ll be digging into this a bit more, as they’ve produced some pretty interesting data sets and assumptions about where people are actually training.  But stay tuned for that more down the road as I’d like to make it more about industry trends than just what Tacx is doing.

Oh – and before I forget, the trainer supports all the usual stuff you’ve come to expect:

– Dual ANT+/Bluetooth Smart support, including FE-C and FTMS, plus power/speed/cadence broadcasting
– Axle Compatibility: Race 130mm, MTB 135mm, 142x12mm, 148x12mm
– Cassette compatibility of 8 through 11 speed cassettes (you do have to supply your own)
– Max 15% supported incline
– Max 2,000w supported resistance
– Requires power cable/be plugged in
– Requires calibration/spindown occasionally (unlike Tacx Neo)

Ultimately, as I said above, the changes here on the Flux 2 may appear minor (especially cause it looks almost identical), but are kinda like the shift from the KICKR 2017 to KICKR 2018 – behind the scenes impact of those changes is actually quite important.  In the case of Tacx with the Flux 2 it makes the trainer highly appealing to those focused on climbing, or in the case of Wahoo’s KICKR changes it makes it appealing for those that appreciate their hearing. But that’s a whole different topic.

Wrap Up:


Of course, there’s plenty of history with the Flux lineup. It got off to a very rough start with the first generation units for the first few months suffering all sorts of manufacturing QA problems. Tacx eventually sorted those issues out and since then the Flux has found smooth sailing and plenty of popularity.  Still, there’s a pile of testing that I’ll be looking forward to digging into once I get my hands on a rideable unit. At the show, the only thing rideable about the Flux 2 shown there was the turntable it sat on.

It sounds like Tacx will be releasing the Flux 2 in low volumes from September, and then at full volume from October.  That’s a bit late in the trainer season curve, even assuming there’s no delays or the like.  Hopefully they can keep things on the straight and narrow.

Either way – between the new KICKR CORE and the Tacx Flux 2, alongside the Elite Direto – it’s shaping up to be a really strong year at the $899 price point. Let the battles begin!

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  1. Mike

    I wonder what’s the noise situation like with the new model.

  2. Antoine nguyen

    Nothing about reliability improvements?

    • Most of that you saw inline within the Flux 1 manufacturing over the course of time, especially in that first year. I’ve heard essentially zero complaints in the last 8-12 months from folks on the Flux 1.

    • Nick

      I have just received Flux #3. It was built in the past few weeks apparently. First 10km was nice and silent and now a sound is starting to come from the unit. I’m going to give it a bit more time to see if it settles but these units are still far from being fault free.

    • VLD

      I had two Flux since september 2017 and decided to go for a Neo due to problems with the Flux. Worst experience ever in terms of product and customers service.

  3. Andy CS

    In a Flux x Direto x Kickr Core, my problem with the Flux is that it does not fold for storage. The Direto is just too noisy for the apartment. These are both eliminators for me personally.
    I think Wahoo will have a great success on the hands with the Core if there’s no flagrant fault with it.

    • Agree. The fact that the Core is silent is the knife.

    • Julio

      I agree with you, that the Direto is noisy. But he is only in high gears with a fast spinning flywheel noisy. I use the direto only for interval-training and i always use the lowest gear and have no complaints from my neighbours.

  4. Rajnith

    Before buying a flux people probably would want to do some research and see the feedback from this facebook group link to facebook.com

    good luck for the new version I had 3 replacement of the flux v1 and this has been quite a nightmare

    • zom

      Yea, I too have been concerned with the quality control of the Flux. Check the Amazon reviews as well, really terrible. I love Ray’s reviews, but they are N=1 and are not indicative necessarily of overall failure rates… do your due diligence before dropping your money imo.

  5. Oleg

    I found Flux 1 prices dropped as low as 550 Euro, and thought all early problems solved. Reading comments above, I started thinking I better go with Direto for 610 Euro.

  6. PeterF

    The 15% @ 10kph is a big thing for me. How does this compare to the Neo, is it even better in this respect?

    • Greg

      Would also love to have a direct comparison of the main contenders (wahoo kickr, Tacx neo, etc.) on this specific topic. I do train for mountainbike and am very often confronted to high slopes which require high power at very low speeds (~350W / 6kph / 80rpm). Is there anywere to look for such documentation (max power vs speed) ?

    • Yup, on the near-term docket for sure.

    • DaveG

      Ray, it would be great if, for you next trainer guide, you could find a way to compare max incline at a realistic speed. I bought a CycleOps Magnus thinking that the spec’ed 15% max incline would be more than enough. But In reality it maxes out at maybe 9% when going 6 or 7mph (and me weighing 180lbs). That is a huge discrepancy between the spec and real usage

    • Yup, that’s exactly what I’m working on (with multiple companies). It’s a bit trickier than folks want to make it seem, to ensure you can correctly compare against multiple companies/trainers.

      But that’s the idea, and all the trainer companies I’ve talked to it are down for it.

    • Joao

      Hi Rey, How does this compare to the Elite Directo?

      In Directo, i will not be able to have the 100% realistic feel on Zwift simulate a 14% ascend?


  7. Nathan B

    Just a quick question.

    What does the spin down consist of for this trainer? My old man has a Neo, and the lack of spin down required is amazing.

    I’ve got an entry level Tacx Flow Smart T2240 (and a power meter fortunately) and the spin down requires me to warm the bike (tire) up, then use the app to ride to 30kph (?) and stop pedalling, then I have to tighten or loosen the resistance on the tire to match up with a green line on the app.

    Do you have to fiddle with a dial or anything on this when calibrating? Or is is something like a back pedal akin to Power pedals, or Zero offset with a Crank PM?

    • Roady

      If it’s anything the same as the Flux 1 (which I would expect!) then it’s very similar to your experience with the Flow Smart (and my old Vortex Smart) but doesn’t require any ‘wheel tightening’. You basically pedal up to speed and then spindown, the offset result is then automatically set/applied by the trainer.

      Just to expand and rather than start another comment – Flux 1 owner here since February. Lots of initial accuracy issues which seem to settle down over the first few hundred miles on Zwift. Still not totally happy with it’s accuracy during high power sprints/kicks and the noise but with the hassle of sending it back (again!) I’ve stuck with it. Wish I’d bought a Direto! Now KICKR Core seems another very valid alternative.

    • When using a power meter as power source, the spin down is not necessary. I just occasionally do spin downs on my wheel-on trainer since i have a power meter. I still keep the tyre-pressure constant to preserve the road-feel and responsiveness, but for smaller deviations of the set incline i don’t care because i have to use less than 100% trainer difficulty on Zwift anyway to avoid slipping at steep sections.

  8. Greg Bassett

    Will all these new trainers handle a bike with disc brakes? My Kickr2 does not. I’ll be replacing it later this year and want to be sure I don’t get a new trainer that does not handle all my bikes.

    • Nathan B

      From above:

      Axle Compatibility: Race 130mm, MTB 135mm, 142x12mm, 148x12mm

      So I guess as long as you’ve got one of those standards, then you should be ok.

    • Dan G

      Axle standards and clearance for disc brake calipers are very different things.

  9. ReHMn

    Hi Ray,

    Will you do a vlog about Eurobike on your YouTube channel?

    • Sorta. I’ll do my annual walk-through of the DCR Eurobike RV (cause that’s fun for me to look back on). Then I’ll also do something down on the Stelvio with what tech I’m using (like last year I did in the Swiss Alps).

      But mostly I’ve been doing videos on all sorts of specific Eurobike Tech.

      Oh, and I’ve actually got a pre-Eurobike Behind the Scenes VLOG I shot that shows what it’s like at the DCR Cave as all the new stuff comes in. I’ll release that later this week. It’s a one-shot-wonder.

  10. Devi Wolthuizen

    Hi Ray,

    I’m in the run for a new trainer for coming winter (still have the older Bushido (not so) smart).
    How would you compare the Tacx Flux 2 to the new Wahoo Kickr Core, as in what would you value more:
    * Doing high wattages (grades) at lower speeds (Flux 2) or
    * Trainer being silent? (Kickr Core)


  11. I wonder how the tariff threats will impact trainer prices if they become real

    • We asked that. Tacx has seen no aspect of it’s biz impacted by it.

      Most other companies in the space have had no impact either, and even Stages’s impact is very minimal as only a single SKU and even then the way the tariff is it’s not 25% of the retail price, but rather the component price. So mostly negligible.

      Still, most companies we talked to are shifting manuf out of China (and were doing it already, largely for non-presidential reasons). Companies are going to Vietnam and Singapore, with a side of Taipei.

  12. Wesley Wuyts

    Interesting stuff about the high wattages/grades at lower speed. Did not know about this.

    How does this compare to the new Kickr(core) and old 2017 Kickr specs? Was it lacking too in that area?

  13. MartinR

    No news about the NEO?
    Would like to see at least a handle for better portability. Heck, it’s the only trainer that can be used outdoors without power, but it’s so cumbersome.
    Also the disc brake/frame clearance/compatibility should be better. Tacx, are you listening? 😉

  14. Ben

    Not sure if anyone is still tracking such things but my Tacx Flux bought in late April 2018 was defective, I am going through all sorts of rigmarole to get it exchanged. Tacx (from Holland) have diagnosed it as requiring replacement but naturally the local bike shop in Australia says we won’t take Tacx’s word for it, we have to send it to our distributor who will eventually do something about it. Just hopeless, I don’t see how they’ve really lifted their game at all and would not trust a Flux 2 either.

    • Nick Johnston

      My experience replacing 2 Fluxes has been quite different. I email my LBS with a video of the noise and ask for a replacement. They forward email to their Tacx rep who arranges the replacement. I get the call its arrived so I take old one in and swap it for the new one. That’s how it should work IMO. At least that’s how it works in NZ.

    • Ben

      That’s quite good! I had to really twist the arm of the store today, even with the Australian distributor saying in writing ‘we will provide you a new unit within 3 days’ they were reluctant.

      I was quite sympathetic to their predicament but when they had Tacx proper and the local distributor (Sheppard Cycles) saying ‘replace it’ their attitude needed to change..

      But they did, and tomorrow I should be able to swap it over, hopefully it’s ok! ;o)

  15. VicP

    Hi, Ray
    I’m interested in your comments about the shift to the trainer resistance floor, since I’m one of those smaller riders. But I’m no sure I’ve understood. Could you please elaborate a bit on that?

  16. Matthew


    On this point:

    “In talking with Tacx they showed charts of how they’re starting to re-architect their trainers a bit to focus more on the specific zones people are actually riding in, rather than going for mythical 24% at 50KPH type specs. I’ll be digging into this a bit more, as they’ve produced some pretty interesting data sets and assumptions about where people are actually training. But stay tuned for that more down the road as I’d like to make it more about industry trends than just what Tacx is doing.”

    It would be great if you could (maybe you already are) work with TrainerRoad (I’m making the assumption that TrainerRoad has a pretty large user base that would provide a solid sample) to get data from them on actual wattage / speeds that people are using for indoor workouts, and then us that for evaluating trainer performance.

  17. TD


    Just a random question.
    Can you control the FLUX 2 with a WAHOO BOLT as control unit?
    Fe. changing/increasing or decreasing wattage on the BOLT, changing it also on the FLUX?

  18. kestas

    Shouldn’t easily measurable max torque in Nm being used to compare trainers instead of some mythical grade % ? We can discuss how to ‘correctly’ convert Nm to % for an end user. But when directly comparing trainer to trainer Nm should instantly tell which one is better at ‘grade simulation’.

    • Giles E

      Totally agree, at the very least all trainer companies need to agree to advertise max % grade at the same speed for the same weight.

  19. Callum

    Seen posts above – any advice as im looking for my first trainer. Tacx Flux v1 new is now £525, do I get that or wait and and get the core for £699?

  20. Carla Ever

    Will it be able to handle a long cage derailleur? The old flux could only be used with short cage derailleurs

  21. Richard Ellis

    Is there just one model of the new Flux, my local bike shop (Tacx stockist) informed me that there will be a Flux 2 & Flux S models available?

  22. Laurence

    Where can you find information on other Turbos about what speed you need to maintain to achieve a certain gradient?


  23. Jānis Vaskis

    how close is the Flux2? at least in Tacx web nothing about it…

  24. Devi Wolthuizen


    If you are in the trainer market for a new direct drive trainer (sub €800,-): which would you recommend at this moment for the comming winter?
    – Tacx Flux 1
    – Elite Direto
    – Wahoo Kickr Core

    or hold your money and wait a bit for the Tacx Flux 2 review and decide then?

    I can wait a bit, but want to have a new one before the winter.


    • (Just copying my answer from the duplicate on the other thread)

      In that scenario, it really just depends on how much you care about sound. If that doesn’t bother you (or if you have a loud fan), you could save the 250EUR and pickup the Flux 1 and likely be happy. I would note that if you’re a bit heavier (like solidly 00kg+) and like riding hills a lot, then you might want to look to the CORE instead. But if you’re lighter than that you’d never have an issue.

      The CORE will give you a bit more inertia, but again, I suspect most people wouldn’t care a ton if they could spend 250EUR on some other gizmo or gadget. Heck, that buys a new Wahoo BOLT or Garmin Edge 520 (maybe even 520 Plus) these days.

      As for waiting for a Flux 2 review, i suspect that’s going to be a while. Like, late October or November at the earliest by the sounds of it.

    • Tuomas


      Firstly, thanks for awesome blog and reviews!

      Any news when you would review Tacx Flux 2?


    • Once I have a unit. That was supposed to happen this past week, but hasn’t quite yet. Right now for new trainers coming in, I’m on about a 7-14 day cycle once they hit my doorstep.

  25. nm

    Is Wahoo doing the same thing with their Core trainer as Tacx is with the Flux 2 by lowering the power to sustain a 15% grade?

    • Not sure entirely. The power required is very similiar to that of the KICKR 2017 though, which one doesn’t really hear much complaints in terms of trainer floor or weight ratios.

  26. Mark brown

    Hi I can get the version 1 trainer for £405 approx $525 on a deal is it worth the money or should I just wait for the new version to be available. I will use the trainer for sufferfest or Zwift, not sure which at the moment.

  27. Jon

    Looks like they have changed the Flux 2 into the Flux S. They’ve lowered the price point even more but also downgraded the max power and slope settings. I’m sure DCR will be releasing and update/review soon.

  28. Dennis

    Only adding a 12mm thru-axle adapter, just when 10mm becomes the norm for road bikes with disc brakes. That seems a bit backwards looking.

  29. Robert

    Tacx advertises the Flux 2 as being “the most silent flywheel equipped trainer available.” True or false?

  30. Robert

    Can you offer a preliminary recommendation Kickr Core versus Flux 2?

    • I haven’t ridden a Flux 2 (even for 2 seconds), so it’s hard to say. But spec-wise I don’t think it’s any better than the CORE, and more importantly for some, it’s not silent like the CORE.