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Power Discrepancy - Kickr Core v p1 pedals
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Have had P1 pedals for about 4 years, recently switched to a Core. What is an acceptable margin? This seems pretty high to me (maybe it isn't), and makes me wonder whether I should use P1 as power source since that is what I will have on the road.


Did the Kickr spindown, calibrated the P1s on Edge.

What is an acceptable discrepancy?




Last edited by: ChrisM: Jan 30, 21 13:44
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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P1 is generally considered to be very accurate...

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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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Always try to use the same power source whenever possible anyways.

Go with the P1
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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Looks similar to mine.

I’m reading both pedals via ANT+.

Also we are measuring power at 2 different places.

I use the pedals, not my Kickr as I’m using the pedals outside and racing. Consistent. Even if wrong.
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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what is even worst is the pedals are reading lower.

Even if both were accurate, the kickr should read 2 or 3% lower to take in account drive efficiency/loss.

I'm guessing you have the crank length properly set on the Garmin ?
You have 2 sided pedals ?
Last edited by: marcag: Jan 30, 21 16:34
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Re: Power Discrepancy - Kickr Core v p1 pedals [marcag] [ In reply to ]
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My mistake. My pedals higher than Kickr.
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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Hmm, seems high to me. If it was a big discrepancy the other way I'd say it's likely drivetrain related, but in this case if the core is calibrated, I'm not sure.

I'd just use the P1 pedals as your power source; you'll be using them as your power meter anyways and the p1/p2 pedals are also known for their accuracy, so I'd bet the P1 pedals are the "real" numbers.
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Re: Power Discrepancy - Kickr Core v p1 pedals [marcag] [ In reply to ]
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marcag wrote:
what is even worst is the pedals are reading lower.

Even if both were accurate, the kickr should read 2 or 3% lower to take in account drive efficiency/loss.

I'm guessing you have the crank length properly set on the Garmin ?
You have 2 sided pedals ?

Yes to both
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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I'm wrestling with a very similar problem. I'm trying to get rid of my TrainerRoad account and control my Kickr Core with my Garmin 945. My problem is there doesn't seem to be a way to calibrate the trainer with the 945.
  • I do a workout with the TrainerRoad app controlling the Kickr Core. I also record the workout on my 945 which is reading power from my pedals. After the workout the two different recording sessions are extremely similar.
  • I started using the 945 to control the trainer. After a few rides, WKO5 thinks my FTP has jumped 15 watts.
  • I tried using the app from http://imobileintervals.com/ to control the trainer, however it is consistently reading 10+ watts higher than my pedals.

I think my problem is the 945 has no way to calibrate with the trainer. What I don't know is when a calibration is run, is it stored on the trainer or on the phone app? I suspect that if I run a calibration on my phone using the Wahoo app or TrainerRoad app then the calibration number is stored directly in the app. Anything else that tries to use the trainer will have no information about the calibration.
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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ChrisM wrote:
marcag wrote:
what is even worst is the pedals are reading lower.

Even if both were accurate, the kickr should read 2 or 3% lower to take in account drive efficiency/loss.

I'm guessing you have the crank length properly set on the Garmin ?
You have 2 sided pedals ?


Yes to both

The easiest solution is to use the pedals to feed the Kickr.

If it were me, I'd do a static weight test on the pedals to see if they are accurate. I think you can do it with the PT pedals, an PT expert could chime in
Another solution would be to test using your computrainer, if you still have it.
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Re: Power Discrepancy - Kickr Core v p1 pedals [marcag] [ In reply to ]
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marcag wrote:
ChrisM wrote:
marcag wrote:
what is even worst is the pedals are reading lower.

Even if both were accurate, the kickr should read 2 or 3% lower to take in account drive efficiency/loss.

I'm guessing you have the crank length properly set on the Garmin ?
You have 2 sided pedals ?


Yes to both

The easiest solution is to use the pedals to feed the Kickr.

If it were me, I'd do a static weight test on the pedals to see if they are accurate. I think you can do it with the PT pedals, an PT expert could chime in
Another solution would be to test using your computrainer, if you still have it.

I do, but broken down. Wish I had known about Zwift power when it was set up. I do know (at least in erg) that the CT amd P1 were waaaay off above 220 ish, just eyeballing the two
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Re: Power Discrepancy - Kickr Core v p1 pedals [ChrisM] [ In reply to ]
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I have 4 PMs: KICR Core, P1, PT G3 hub and Computrainer (CT).

The KICK Core, PT G3 hub and CT always read within a few Watts of each other, and have been very consistent. The P1 has read consistently and significantly higher, 15-25W higher in most cases and outside the range of expected drivetrain efficiency unless my chains are really bad!

I just convert manually depending on if I'm riding inside or outside. I assume the P1 is incorrect as the others are very consistent, but I haven't tried to adjust yet.
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