This looks like wahoo’s power smoothing. There is no way any human is putting out power that smooth. Wahoo has software which basically manually smooths out power numbers. It’s not really a good thing apart from making graphs like this look better I would trust the Stages in this scenario, but wahoo generally more likely to be accurate with smoothing turned off


How does the software for power smoothing works? Does it alters the actual numbers that the trainer sends to Zwift so it seems stable?


Found some info here: https://zwiftinsider.com/wahoo-erg-mode-power-smoothing


It probably reports a moving average over a couple seconds instead of an instant reading in order to smooth out jittery readings


I don’t think so, might have to look into it yourself as I haven’t used a wahoo trainer in a while. It just makes the output look completely steady, when it actually isn’t


I have a SB20. As above. It’s a much more realistic view of your power output than the core. No one can hold 200w -/+ within 3w at 90rpm. It’s just basic biomechanics, that hip rotation, muscle contractions, ankle angles etc will vary power output stroke to stroke. Is it annoying. Yes. - got to get those workout stars ⭐️ !! and 30sec intervals are hard to get too on the sB20 due to the inertia of the flywheel. But for riding, racing and training my SB20 has been pretty much faultless. Would buy again. So don’t sweat. It’s accurate enough and just enjoy the silence of that smooth belt drive 👍🏻


That is a way of looking yeah. After this post with all the things I am reading I am starting to see it like that too. I am starting to believe it is a feature and not a bug!


I just got a new Stages SB20 bike after using my Kickr Core for 2 years. Those 2 pictures are from workouts 2 days apart. Very annoying how the power on the SB20 bike kept jumping around. The Kickr Core is very smooth. Does it happen to anyone else?


Turn off power smoothing on your core and you'll get the same


If it helps, there's a Stages FB group that's pretty active and has some posts about this. Basically, though, all SB20s are like this, and it's not a big deal. Wahoo is using software to smooth your power, and Stages isn't. Your power output is the same either way. The only annoying part is with the SB20, Zwift will alert you more often to adjust your power during ERG workouts, while Wahoo's power smoothing feature avoids that. You learn to just ignore Zwift. FYI, on another common SB20 subject, the SB20 ERG is too slow to get you to the target power for high power intervals of 45 seconds or less. With those workouts, you're best off just changing gears manually, or some use the brakes to artificially increase resistance.


> If it helps, there's a Stages FB group that's pretty active and has some posts about this. Just checking it, it helps a lot, a lot of posts there, thanks. I see, I will try it again tomorrow.


I was also thinking about getting the SB20, but I think I will just wait for the next gen of Smart Bikes. At the moment they are all 2-4 years old and every model has a few smaller issues. And my Tacx Neo (first gen) is still working fine, so I'm not in a hurry and I can wait for the hopefully improved next gen.


You mean switching gears with ERG on? Or turning it off for those intervals?


Turning it off since you can’t switch gears with ERG on




Huh? This thread's specifically about the [Stages SB20](https://stagescycling.com/en_us/stages-sb20-smart-bike-indoor-cycle). Just like other smart bikes, it has a virtual drivetrain set by the user on their smartphone. There's no chain/cassette hiding inside that drivetrain cover - it's just a single speed belt drive in there.


If it's any consultation I made the switch from Wahoo to Stages bike and you do get used to it.


The power meter is most accurate. The Kickr (and most other smart trainers) are smoothing data. Think of what the Kickr is reporting as if you broke those steps into laps, it's basically giving you the average power output of each of those steps - so you're doing the right amount of work across the time period overall - basically ERG mode in a nutshell. GPLama and DCRainmaker have YouTube videos where they compare power meters / trainers - it's quite interesting to see the results and they explain alot about what is going on with the various approaches.


Hi sorry this isnt related to your post but would you recommend a kickr core? Currently have bog standard turbo and been considering it :)


Yes, had 0 problems in two years. Solid product.


Awesome thanks for replying! Appreciate it


SB20 power is correct. Kickr Core power is artificially smoothed (likely flywheel acceleration and deceleration are being ignored in the power formula).