Expected power differance from quarq dzero and neo

hi guys, I put my quark from gravel bike onto neo to check calibration it’s reading 10 watt higher then neo on ave over a 45 min session,

would you say this is normal for a crank based to direct drive system

what was your average power for the 45 minutes? I’m guessing 10 watts is a pretty small percentage of that.

Variation in power readings is different across equipment for any number of reasons. You could just as easily find a 10w discrepancy between 2 different crank based PMs

was only neo 145 watts on a 4 min on 4 min off so and quark 155. I’m going to redo ftp on quark to establish a ftp for outdoor based rides.

As others noted every PM is probably different and accuracy as quoted may not always be completely correct (I personally think this statement is most true for wheel-on smart trainers, which I know isn’t your question).

My Quarq consistently reads higher than my Assioma duo pedals. It is a slightly smaller difference around 200W (maybe 5W higher) and larger around 350W (more like 12-15W higher).

My Kickr had more variation and difference compared to Duos but I haven’t been recording the Kickr lately so can’t provide a great comparison.

Your difference seems like a high percentage given how many people not the accuracy/consistency of each of those pieces of equipment.

10w is a lot. Is your cassette rubbing your frame? Is your cassette loose?

have you calibrated your Quarq after warming it up? Neo?

How are you seeing the power #? keep in mind different services calculate power a bit differently.

nope no and no. calibrated crank after warmup, neo doesn’t need calibrating. I’ve got a set of vectors I’m going to put on as well,
both workouts where recorded on TR one on phone another on

when I do the ramp testing will do it on both again and see if its consistant or changes with increased power.

I’d grab a power file (.fit) from each on the same ride, not in a workout, and use DC Rainmakers comparison tool. Figure out if its a cadence or torque difference. You can’t just look at screens.

Are you in EGR mode? Because the trainer will lie to the app. See Kickr here - https://media.dcrainmaker.com/wp-content/cache/comment-plus/1333510-400x300.png?1451903054

Unless you’re in a really weird gear, have a heavily worn/dirty chain, 10w is way off. You probably have +10w drivetrain loss at 200w, but the Neo should know that and add a correction.

Edit: Looks like this is common https://forums.garmin.com/sports-fitness/indoor-training/f/tacx-neo-2t-898484771/212372/power-comparison-with-vector-3-pedals Maybe Tacx doesn’t compensate for drivetrain loss or does smoothing.

Edit2: Looks like the Tacx is shit or over smooth at reading cadence. https://www.dcrainmaker.com/2018/12/tacx-neo-2-smart-trainer-in-depth-review.html https://media.dcrainmaker.com/images/2018/12/image-59.png

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I have 2x quarqs and a neo and the neo reads lower than both of them. The difference is larger at high flywheel speeds (big ring) and lower at low flywheel speeds (little ring). @GPLama has confirmed this with neos iirc

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Maybe your chain is worn. I have the same setup and normally the difference is around 3 watts or so (Quarq higher than Neo). Couple of months ago the difference started to increase and closing in on 10 watts, replaced the chain and went straight back to 3 watts.

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