Normal power meter behavior?

I’ve been using a Kickr Core for a while, generally doing all my rides in Erg mode. I just got a separate power meter (Assioma Duo) and did my first ride with it yesterday (with power match set to auto): https://www.trainerroad.com/career/mcsenn/rides/57469272-red-lake-3

I expected my power graph to be a lot spikier than I’m used to, but is this degree of variation normal? Target power 224W for the work intervals, and I was frequently spiking to +/- 50W around that target.

My average power for the work intervals was consistently higher than target, by 2-3.5%. Shouldn’t power match keep my average closer to target for intervals this long (5 minutes)? Eventually I took the workout intensity down a couple percent to compensate.

Also, I wanted to compare the two sources of power using DC Rainmaker’s analyzer, but when I exported the .fit file from TR there was only one power recording. Is there any way to recover the separate streams? Or the left/right power breakdown?

  • Yes, that is totally normal for a regular power meter.
  • Wahoo defaults to using Power Smoothing in ERG mode. It is terrible, a complete lie and the reason this question comes up every time that someone gets a different power meter or smart trainer.
  • https://youtu.be/7L7hfT0I7E0

  • TR only captures one power source in the workout. If you want to analyze, you need to use a second device to capture a separate file. Then you use both combined to see the comparison.
  • Same issue for L/R data, you need to use a difference device and app than TR. They do not capture that data for use.
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Is it normal to be THIS spiky though? (screenshot from interval 4 of his ride, versus a recent screenshot from my Garmin vectors in erg mode) Power maxes out 375 watts on a 225 watt interval…


And also, for the smart trainer to not properly correct itself over the course of the interval and make him overshoot the targets so regularly? Feels like there’s some issue with powermatch here that’s not quite working as it should.

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FWIW, the 375 was while I was reaching for my mouse to lower the intensity, when my cadence was varying a little bit. In general my cadence looks less stable than yours, but I’m still mostly sticking within a band of ~10 RPMs - I wouldn’t think that’s so drastic to spike my power so much for a few seconds.

In my opinion that’s exceptionally spiky. I also use Assioma Duos in auto power match erg mode. For reference, here’s a 5 minute interval I did today:


The target for the interval was 275W. The big yellow overshoot I had there at the start of the interval was 349W, but then power match kinda did its thing and I settled into a +/- ~35W envelope around my target (maybe I need to work on my stroke smoothness). What is your power smoothing set to?

I’m pretty bummed too that TR discards the left/right data from my pedals. I’ll be even more bummed though in a week or two when Favero releases the firmware update for our pedals that enables cycling dynamics and all that good data doesn’t make it into TR either!

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I would say that is NOT normal and much “spikier” than what’s expected with Powermatch. Also, to get two .fit files simply use your bike computer and record your PM as well as using Powermatch. This way you’ll have your TR .fit file and your head unit’s .fit file. Then you can compare the files with DCR Analyzer.

Also look into Wahoo’s settings on their app. I turn off Erg Mode Power Smoothing and have Control w/ ANT+ Power Meter turned on. Make sure to Calibrate your PM before every ride/workout.

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You might try some testing without power match on and see what you get for data from the pedals alone (in a separate app). I know there are mixed results where it works well for some, and not so well for others. One variable to test here at least.

Thanks for the suggestions everyone, I’ll do some experimenting tonight.

It does look pretty spiky, but I note that your cadence range on those suprathreshold intervals was fairly wide, which will definitely give you more spikey data and it’s magnified as power goes up. Some of the largest spikes happened when cadence changed from 89 to 96 or 89 to 97 or 95 to 101, which you’d expect in erg mode.

In my experience with powermatch and my Vector 3 pedals, my higher power intervals are usually a little more spikey, and the cadence variation makes that more pronounced as well.

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I know it’s also been mentioned a lot over the years.

Small front rather than big ring and try for a straight chain line - I believe is the ideal for erg?