Curious if anyone else has same results, I can be on a Zwift ride on my Kickr direct drive and my watts will vary 10-20 one second it is 120 then goes to 140 then to 130, etc watts up and down with me keeping same cadence and speed. Not sure it’s an issue w trainer or Zwift, would think I could hold a fairly steady watt output on a flat road, Thanks
Hi @Jeff_Gaster
Welcome to the forum.
The image you posted is your PC Frames per second not watts, am I missing something?
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Hi @Jeff_Gaster, do you have your settings in Zwift at instant power or 3 second average power? This is a display option only, it doesn’t effect your actual power output, but it can help “smooth” out the displayed power on the screen.
@Mike_Rowe_PBR HI, I have 3 second average, should I switch to Instant?
I would leave it at 3 sec avg
I wouldn’t spend too much time worrying about it, there is always going to be some variation in your power, even shifting your weight in the saddle or sitting upright will cause it to change.
When in ERG mode, it should hold a constant power regardless of your cadence. If you are seeing variation in ERG mode (doing a workout), then I would be concerned.
Thanks Mike, appreciate it.
One issue is it depends on what power meter you use. If you use a crank-based power meter, that measures power over each pedalstroke. If you use a hub-based power meter (including many smart trainers), power is typically measured over 1 second. But power varies over each pedalstroke, so if you have a cadence of 60 or 90 or 120, no problem, you get an even number of pedalstrokes, but if it’s not an even number of half-pedal-strokes, then you might get a different number of “power strokes” one second to the next. Averaging over 3 seconds helps with this but won’t eliminate it, especially at relatively low cadence.
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That’s the problem I have. Some workouts hold me at steady power and the next day it’s like ERG mode is off even tho the companion app says it’s on and the radio button is checked when I select the workout.
I’m having the same issue - watts are fluctuating by up to 150 W within a single pedal stroke. it’s bouncing all over the place - very frustrating. it makes training futile because I can’t get a relatively consistent watt reading. this does not happen, however, when riding routes. I’ve never had this issue until recently. I’ve performed spin downs and undated all software.
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Is this still an issue? I got a New Tacx Neo2 trainer and the 3second average power doesnt seem to work. The displayed power bounces up to 10W either side of the ERG target
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Mine does the same thing. As with the earlier responses, I don’t think you should really worry about it. As consistent as we think we are, the reality is that our power output varies constantly. 10 watts isn’t a large difference to be concerned with.
In ERG mode the trainer resistance is regularly changing so that you meet the desired wattage target. But if you increase your cadence, even just a bit, the resistance will drop by a bit (after a slight lag), and the opposite will happen if you decrease your cadence. So, unless you can stay at a perfectly consistent cadence the trainer will be constantly increasing and decreasing the resistance while you ‘chase’ the wattage target.
To be varying 10 watts above and below the target with 3s averaging means i’m swinging 30 watts above and below per screen update?
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My wife is getting the same quite regularly. It coincides with a change in resistance as well. It has happened with two different trainers for her.
I also had the same once as well when climbing the alpe… resistance would disappear while still on 10% gradient.
My wife is getting something similar…
Same problem here. Errs tic power numbers in ERG
I’m experiencing this as well recently, regardless if my power source is from my Kickr v5 or my 4iiii PM (both are at 3s ave setting).