I've been using the holidays to pointlessly obsess about my power meter readings (as one does). I have two P2M NGs that I've been comparing with a Neo 2T and and Elite Drivo II.
Long-story-short.. I'm suspecting that the auto-zero function on the NGs may sometimes be causing weird offsets mid-ride, e.g. by kicking in when there is no force detected on the pedals but the conditions are far from stable, e.g. on simulated descents.
If you use a P2M, do you toggle the auto-zero to "off" when indoor training and use manual zero offset instead? If so, do you find that this produces more consistent readings?
The odd thing is, a message once came up on the P2M phone app warning me to turn off auto-zero indoors, but only once (I can't get that message to repeat). So wondering if perhaps it was specific to a particular version of the software (perhaps implying that any issues caused by auto-zero for indoor traning had been ironed out.).
Yes, I over-think things.
Turn off auto-zero indoors on P2M NG?
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TobinHatesYou
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RyanH and I had this conversation in the middle of a Zwift race, stemming mostly from Quarq's new Magic Zero being unreliable.
I turn off auto-zero on the Quarq I use indoors. Ideally it shouldn’t affect anything since any force applied by the chain during coasting should be negligible, but I’ve occasionally noticed an offset change after a period of coasting. I don’t have a Neo, so it’s not even the “downhill drive” causing it in my case. It could certainly exacerbate the problem, as could packing too much, too thick of a grease into your freehub driver.
Either way it's not something I worry about since auto-zero is only a feature on spider-based PMs. Crank and pedal based PMs always detect some amount of force/strain so they can only auto-zero when you are off the bike anyway.
I turn off auto-zero on the Quarq I use indoors. Ideally it shouldn’t affect anything since any force applied by the chain during coasting should be negligible, but I’ve occasionally noticed an offset change after a period of coasting. I don’t have a Neo, so it’s not even the “downhill drive” causing it in my case. It could certainly exacerbate the problem, as could packing too much, too thick of a grease into your freehub driver.
Either way it's not something I worry about since auto-zero is only a feature on spider-based PMs. Crank and pedal based PMs always detect some amount of force/strain so they can only auto-zero when you are off the bike anyway.
I think I'll try turning it off indoors.
Yes, any force applied during coasting shoud be negligible, but I suppose the thing might auto-zero while you are applying very gentle force (enough to account for 4 or 5 watts but not enough to deactivate the auto-zero, depending on how it works / timing etc?).
I believe that the NG does its temperature compensation dynamically (whether or not force is being applied), so I guess I could just auto-zero at the start.
Yes, any force applied during coasting shoud be negligible, but I suppose the thing might auto-zero while you are applying very gentle force (enough to account for 4 or 5 watts but not enough to deactivate the auto-zero, depending on how it works / timing etc?).
I believe that the NG does its temperature compensation dynamically (whether or not force is being applied), so I guess I could just auto-zero at the start.
