Going from wheel off to wheel on trainer

Currently I’ve got a Tacx Flux 2 and I didn’t realise until the recent podcast how inaccurate it was in ERG mode. So knowing that I’m looking to replace it, I can return it to the place I bought it from but I’m not sure what to replace it with. I’d like to buy from the same place (I’ve got a 20% off voucher) so I’m a little limited to models, in terms of wheel off there’s the cycleops h2 and elite direto.

I was all ready to order the h2 when I thought about maybe going slightly backwards and getting a wheel on trainer. It would allow me to be a bit more flexible where I do my training and give me brownie points with the wife if my bike isn’t permantly in the dining room. Also with the money saved I could get myself some power pedals.

As all of my turbo riding is “training” the feel of the trainer doesn’t matter so much, but other than that I can’t see any big downsides to going wheel on + power pedals. Is there anything I’m missing out on (aside from tyre wear).

Thanks :slight_smile:

To add, the wheel on I was looking at is the cycleops m2

I ride a wheel on trainer and will upgrade to a smart trainer when $$& permits.

There are a few workouts on trainer road that aren’t that well suited to a dumb trainer. (Specifically the ones with rolling power targets: Geiger) Doesn’t effect the training…unless your ocd with hitting then target power.

For clarity, the CycleOps M2 the OP mentions considering for a wheel-on trainer, is actually a smart trainer. So there are no concerns about dumb trainers related here.

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If you think a wheel off trainer is inaccurate just wait until you have to deal with all the fun of maintaining consistency with a wheel on trainer! Don’t do it!

P.s. I havent gotten to the latest podcast (presumably the one with @dcrainmaker ). Cliff notes on how ‘bad’ a flux 2 is?

That’s why I was thinking get some power pedals - that way the trainer just adds resistance and the power comes from the pedals.

10-20% I think he said

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I have a Tacx Flux S and this is the first time Im hearing of them being wildly inaccurate… I find it hard to believe theyd be less accurate than a wheel on trainer…


Very interesting! Thanks for sharing.
Link to Screenshot: https://www.dcrainmaker.com/2018/07/first-look-tacx-announces-new-flux-2-smart-trainer.html

For fun, see attached screenshot for how badly the Flux 2 handles in ERG mode. This is compared to two the PowerTap P2 and Stages LR. There’s two core issues:

A) It can’t hold ERG mode properly at a given level without large swings (for which Tacx has confirmed)
B) It’s simply inaccurate by 10-20% (for which Tacx has also confirmed)

I started calling this out back in March on my post in the comments section, waiting for fixes. I had other warnings as well on it before finally giving up and just sticking a big old ‘Do not buy’ in bold at the top. It’s just not good.

The Flux 2 was also quietly updated at Eurobike, dubbed the Tacx Flux 2.1, to address these. More on that soonish.


Also note, this is specific to ERG mode, not SIM mode. And it doesn’t matter if it’s ERG mode on TR or Zwift, I tested both and both suck with the Flux 2.

However, SIM mode, such as regular Zwift riding, is just fine. See attached for that (the spike you see is me doing a mid-ride calibration



You can read through the thread I posted a couple of months ago when I was trying to decide between a used Snap or a new Core. I have a power meter, so I use powermatch. I’ve never really had issues with tires wearing out with my old PowerBeamPro, but I also split my training between indoors and outdoors. I ended up with the used Snap, although I haven’t done much on it since it’s still nice here and I’m still doing intervals outdoors. I think you’ll really like having the power meter on the bike because it means you’ll get power outdoors as well as indoors.

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My Flux S displays this exact behavior, is it just the 2 you tested?

If erg mode is the concern… then why not get the h2 or h3 as Ray also mentioned how great they are for erg?

I have the same. The idea of a direct drive is fancy…but I really wonder if I will appreciate the $800+ in extra cost.

If you’re not obsessed with a direct drive trainer there’s one system that could really change your value equation. You can pick up the inside ride ultimate Flex and connect your power pedals as the source. Then you have decent smart resistance with full rocking control, all floating on a motion platform. And they can be converted to smart rollers just in case you get the itch to ride free. I love mine… they rock!

I tested both. Zero issues with Flux S in that regard. Pretty different internals actually.

Bit out of my price range - plus I don’t think they are available in the U.K.

But if you take the money you save and get a power meter that you can now also use for outdoor riding, and let that also control your wheel on smart trainer’s erg mode, you are coming out well ahead.


That’s exactly my thinking.

I’ve ordered an M2 which works out at £280 and a set of Vector 3’s for £400 with %10 cashback to come. So about breakeven in the end.