Any way to reliably calibrate PowerPod against real world performance?

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JRandomUser
Posts: 6
Joined: Thu May 09, 2019 4:20 pm

Any way to reliably calibrate PowerPod against real world performance?

Post by JRandomUser »

It's driving me nuts that I cannot tell if my PowerPod is giving me accurate power numbers.

I've just tried comparing PowerPod power statistics for a ride with estimated power from Strava, by exporting the FIT file for the ride from Garmin Connect, stripping the power data out and uploading to Strava. The result is that PowerPod is giving considerably higher power figures than Strava (about 30% more). I realise this doesn't tell me much - Strava has much less data to go on so I can't trust its numbers either.

I understand it's possible to get pretty good accuracy out of a PowerPod, but It seems the only way to take the guesswork out that and get numbers close to my real world power output, would be to calibrate it against a known-good power meter - i.e. a DFPM. That's not really an option - my bike is basically not compatible with any inexpensive (non-pedal based) DFPM, due to being belt drive with a weird chain-set.

How can I alleviate my accuracy anxiety?
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Any way to reliably calibrate PowerPod against real world performance?

Post by Velocomp »

Just curious: if you had an SRM, or Stages, or PowerTap, or any other DFPM, how would you know if any of them was giving you accurate power numbers? :D

Strava truly GUESSES at power. It has no accurate idea of wind conditions, slope, or acceleration. I would never compare power meter readings to Strava readings.

PowerPod will give you accurate and consistent results if:

1) It is properly attached to the bike (device can't rotate)

2) Rider weight, height, and ride position are accurately entered

3) Device has been properly calibrated (wind speed is consistent with bike speed)

If you post a .ibr ride file I will show you how to check it.

By the way: I have a DFPM on my bike, which I use for CdA measurements. About a week ago my CdA measurements (from two AeroPods mounted on my bike) both dropped precipitously and without reason; I am now 100% convinced my DFPM is giving me inaccurate numbers. I am actually going to attach another DFPM to verify this; when I do I will post my analysis.
John Hamann
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