I recently decided to try to cross test my power meters for accuracy. I was hoping to find pretty consistent results like we see on DCR/GPLama vids, but no such luck. Every PM calibrated (zeroed) on head unit prior to each ride. Crank lengths consistent (175mm) and set-up correctly for pedals. Some…

I went down this rabbit hole a couple of years ago. I found out I had a significant L/R imbalance. Not only though, did it vary with intensity and fatigue but also was completely different inside or out. I put that bit down to the bike not moving around on the turbo trainer as opposed to the road. I…

Right. Years ago when we were collecting all the packets sent from an ANT+ power meter, we saw that different head units did (slightly) different things with the data they received. This iGPSport head unit sounds excessive, but the general issue that every manufacturer has slightly different proprie…

I went down this rabbit hole four years ago. My only conclusion was to use one power meter for training. Bypass the trainer’s power meter at all costs. If you really train on two bikes, then get power meters (like pedals) that can be adjusted to match each other. I also found out that my Stages per…

I haven’t done extensive indoor testing on these because 1) it’s outdoor riding season :joy: and 2) I’m not motivated to swap cassettes & drivers on trainer to figure this out. I have however done outdoor intervals, and the discrepancies are fairly consistent at around 10% I am aware of the challen…

[image] AJS914: My only conclusion was to use one power meter for training. Bypass the trainer’s power meter at all costs. If you really train on two bikes, then get power meters (like pedals) Agreed. I have two sets of the same power pedals, they seem to match each other. I use them for eve…

[image] carytb: I eventually moved on from this as insanity beckoned. Indeed.

So the cadences appear to agree pretty well, so the difference must be from the torque measurements. It also might appear that the torque difference grows with higher torque? Check that you have the right crank length for the Assiomas, and do a static check on the Quarq. Quarq used to let you do a …

You can find variance is non-linear with non-strain gauge meters. So two devices may vary by 10% at 200W, 1% at 100W and 20% at 300W.

I’ve mentioned this before but it really would be great if trainerroad looked into the data and answered this question once and for all. They have millions(?) of rides where users have used power match and I believe from interactions with trainerroad support staff that power data is recorded and st…

Power meter accuracy comparison - Down the rabbit hole

Equipment

AlphaDogCycling May 27, 2024, 4:43pm 10

FYI: If you are using Duracell batteries, don’t use them in the Quarq. Quoting myself in a different thread: Quarq DZero Dub PM suddenly not measuring power - #5 by AlphaDogCycling

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Power meter accuracy comparison - Down the rabbit hole

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