Has erg algorithm changed?

I hadn’t used erg for quite some time but did today. Previously erg function locked-in very tight on the set wattage and showed a graph absolutely flat across the interval top, looking like a mesa. Today varied above and below the set wattage but ultimately yielded a watt average for the interval just a few watts above the set spec and the graph definitely no longer was flat across the tops of the intervals.

Has Zwift changed the ergo algorithm?
Bill Black

Hello Bill,

No, Zwift hasn’t changed. I assume you previously had some sort of ERG smoothing setting on your trainer turned on, is it a wahoo?

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Yes, it’s a Wahoo Kickr (2018) and I’m runnig W10 on a PC — I’m not aware of any smoothing setting and I certainly never activated or deactivated any such setting.

believe it or not, it is there, in the wahoo app, not on Zwift.

I’ll have to check it out. I use the Wahoo app for calibration and perhaps I inadvertently activated smoothing when I last calibrated the Kickr?

I checked the Wahoo Kickr settings and smoothing was not on. However, problem was solved by uninstalling and then reinstalling Zwift.

if it is off you will see the spikey power graph as you explained earlier, by turning it on you will get the nice “smooth” lines when in ERG mode as in the screenshot below:

The spikey graph is the correct one and the smooth one is kind of lying to you. Looks nicer but it isn’t the power you’re actually doing.


I think it averages out to be pretty darn close though right?

yeah, i think so, never had a trainer that does it.

i kind of also meant that it is just a visual thing and doesn’t affect the in game experience

Yes, very close, although without the Kickr smoothing the average watts for the intervals are 3-4 watts higher than are the averages shown for the same intervals with Kickr smoothing on.