Calibration Ride Off; Fixed By O&B In Isaac; What's up?

[ianc]

I did the firmware upgrade, and did the calibration ride. Everything seemed to go well. I was getting somewhat elevated power numbers, but I was doing 5 min VO2max intervals, and didn't expect things to be super-accurate.

Today I went out on my second ride post-calibration ride. I was trying to to 12 min SS intervals at about 290W. Instead PP was telling me I was putting out 330W without a whole lot of effort. Things were pretty windy, and each time I turned into the wind, I was suddenly putting out 500W without any extra effort either. Then things would settle down a bit.

When I got home, I did an O&B analysis via Isaac, and it tweaked the profile significantly resulting in some more normal looking numbers. Nothing has changed as far as the bike goes; the PP is still in the same mount, in the same position, with nothing blocking it.

I'm starting to think I'm using the PP in a way it's not really meant to be used. (i.e. training in power zones). PP & Isaac seem to be pretty good at giving accurate numbers *after* I get home from the ride, but I'm starting to have serious difficulty trusting the numbers its spitting out *while* I'm riding. I've had this PP for almost a year now, and I'm still not quite sure I'm using it correctly.

Any suggestions?

[Velocomp]

Check Calibration reduces your wind a little bit, and puts your intervals in the 290W zone.

What REALLY affects your results after Check Calibration is the missing cadence, from mile 2 to 3. When you run Check Calibration, you'll find that Isaac forces watts to zero in that section. This is dropped your overall average considerably.

I use my PP for zone training all the time (though I'm not as strong as you). Once you get your profile dialed-in, you should be OK.

I would use the Check Calibration profile for your next ride.

[ianc]

Hmm. The weird thing is--I don't see that 7.5 minute dropout from 06:00-13:30 in Garmin Connect or Strava.

https://connect.garmin.com/modern/activity/1610163961

Any idea why it's missing in the ibike file? Guessing the PP lost signal from the cadence sensor, but the head unit didn't? Does the PP read directly from the cadence sensor, but get HR and speed from the head unit?

Thanks!

[Velocomp]

I don't know why cadence went "missing". Looks like PP temporarily lost the signal...

All signals recorded by PP come directly from the sensors.

[ianc]

Hi John,

One last quick question:

I used my O&B-calibrated ibr to tweak my profile, and now I'm seeing a wind scaling value that I believe may be high.

I have the dual mount from K-edge, which if I remember correctly tends to want a value around 1.7. Isaac is suggesting 2.054. The value *before* the O&B (the one generated by calride) was 2.222.

Is that within normal range of values, or is it indicative of something off?

Thanks!

isaac_profile.jpg (116.82 KiB) Viewed 4045 times

[Velocomp]

The default values in PP are middle-of-the-road estimates for different mounting positions.

The O&B ride dials-in your PP. I would use the value it measured.

[ianc]

Thanks John, you've been a great help!