Is there any direct drive smart trainer without a powermeter?

A light bike doesn't replace good fitness.

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maurice1
Posts: 157
Joined: Mon Dec 19, 2022 12:51 pm
Location: Jura

by maurice1

Looking to get a home trainer again but sadly the one I used the previous years, an elite Suito has now increased in price a lot. I don't want to spend much for just winter and already have powermeters on my bikes, so I don't need the trainer to calculate it again (plus the consistency is valuable)
I definitely don't want a wheel-on because the noise would drive me crazy. My idea of an ideal trainer is one that receives power from my on-bike powermeter to then simulate gradient or even ERG. Is this a thing? Am I asking for too much (or too little :) )?
The units I've had on my radar in the 200-300CHF range (including used) are the Magene T100, Elite Turno, neither of which are smart, and the Xplova noza one (not S) which I can't find anything about but looks a lot like the Magene T100

by Weenie


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usr
Posts: 1023
Joined: Thu Mar 25, 2021 5:58 pm

by usr

I believe that you are greatly overestimating the inherent cost of power metering. The parts are all single-digit at most and without the constraints of having to fit within existing bike part form factors and roadworthy sealing, adequate consistency should be possible at much lower price points. The technology is basically the same a an electronic kitchen scale, with a more powerful chip (and better software). And that computing hardware would be exactly the same for a trainer that skips the internal sensor and relies on connecting to an external powermeter instead.

What you are looking for is a controllable trainer at a low price point, power meter or not. In product portfolios that serve a wide price spectrum, segmentation will mandate that the lower prices can't include a powermeter, but that does not imply that other vendors have to follow the same strategy.

maurice1
Posts: 157
Joined: Mon Dec 19, 2022 12:51 pm
Location: Jura

by maurice1

Thank you, I indeed assumed power meters cost 100+ to manufacture. There would however still be value in always using the same powermeter, no? Because the trainer might have a different calibration and give me a false sense of progress, while my crank PM is what I've used to gather the last 2 years of data.
Is there then a much greater cost for developping ERG/gradient sim in a trainer? Or is this another case of manufacturers willingly stripping their entry levels of ERG mode?

My one need above all else is that I want it to be direct drive and silent enough. I'm okay sacrificing power accuracy, but gradient sim would be a nice plus, even if I enabled 50% in zwift

usr
Posts: 1023
Joined: Thu Mar 25, 2021 5:58 pm

by usr

I try to keep my zwift connected to the Faveros, for consistency and half jokingly (less jokingly than I want to admit?) to keep drivetrain losses out of my times up to the radio tower. No idea if that means that the ERG feedback loop goes through zwift or if that's still just Zwift telling the Neo to do what it thinks is x watts. I hardly ever use ERG outside of injury recovery and that occasional Zwift pyramid test.

Back when I had Neo Watts in Zwift and Favero Watts on the Edge I saw quite some variation in the difference. Never tried to align them (drivetrain losses etc), sampled some "best 20 minutes" data over a winter season to align different sets of pedals on different bikes, getting them to agree on how much they disagree with the Neo. Spread within different 20 minutes bests in the sample group of a single pair of pedals was still quite considerable.

AJS914
Posts: 5499
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

maurice1 wrote:
Wed Oct 25, 2023 11:15 am
Thank you, I indeed assumed power meters cost 100+ to manufacture. There would however still be value in always using the same powermeter, no?
Some trainers (like my Kickr) and most software (Zwift, TrainerRoad) allow you to use the power reading off the bike's power meter.

I have an older Kickr. I take power from my bike's power meter and record it to my Garmin. I control the trainer resistance with the trainer's app and my gears. I only look at the power on my Garmin head unit.

by Weenie


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TobinHatesYou
Posts: 13062
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

All smart trainers perform power measurement. What do you think the resistance unit is doing? It’s changing the brake power being applied to the flywheel based on commands given to it. It is basic functionality that can’t be taken away for cost-saving purposes. Even the KICKR ROLLR has a power meter, it’s just that without consistent tire contact on the rollers, it’s too inaccurate and not used for power reporting.

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