Different calibrations, please check.

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gjmeer
Posts: 6
Joined: Sun Jun 16, 2019 7:30 am

Different calibrations, please check.

Post by gjmeer »

I feel that the calibration of my PP is not going well. That's why I completely restarted yesterday.
I have done a full reset of the PP. I then created a new profile with 'Best Accuracy'.
Afterwards I reach a suitable place for the calibration. Connection of sensors has been successful and is ready for calibration.

The PP first carried out its own calibration. This went well from 0-50, stopped, made a U-turn and further from 51-100. Sounds good.

Then started a calibration trip of 3.2 km O&B (total 6.4 km).
This ride used for 'Check Calibration' option in Isaac. See upload. This calibration trip had the same route for the first kilometer as the first calibration. The calibrations are performed directly one after the other in calm weather conditions and no traffic.

After the calibrations I recorded a ride of 24km that PP based on the first automatic calibration. (See upload 2).

I think the differences between the calibrations are quite large.

Aero Wind: 0.982 (PP Cal) vs 1.027 (Cal Ride)
Friction: 9.297 vs 12.725
Riding Tilt: -0.7 vs -1.1
Wind Scaling: -2,908 vs -2,936

My body weight = 69 kg
Weight of bike & Gear = 14.5 kg
Position PP: Go Pro Front Mount - Giant Conduct (https://images.app.goo.gl/WdaFPFXGzbygusA56)

The differences in the calibrations make the values in the 24km ride quite different, in my opinion:
Peak Watt: 946 (PP Cal) vs 914 (Cal Ride)
5sec Watt: 771 vs 743
10 min Watt: 297 vs 325
20 min Watt: 270 vs 290
Average watts: 196 vs 213

My measured FTP on the Wahoo Kickr indoor trainer is around 240 watts (20 min FTP test), so the values above are quite significant. In addition, I did not even have the impression that I had to go so deep.

Can you check my calibrations? Thanks in advance!
Attachments
PowerPod_2019_06_15_1440_24_km (PP Cal).ibr
(192.85 KiB) Downloaded 150 times
PowerPod_2019_06_15_1440_24_km (Cal Ride).ibr
(217.6 KiB) Downloaded 131 times
PowerPod_2019_06_15_1426_7_km.ibr
(61.01 KiB) Downloaded 132 times
gjmeer
Posts: 6
Joined: Sun Jun 16, 2019 7:30 am

Re: Different calibrations, please check.

Post by gjmeer »

edit:
Hereby a photo of the real place of my PP on my bike:
The windport is about 84cm above the ground.

https://drive.google.com/open?id=1KBMLc ... SKJjITMPAl
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Different calibrations, please check.

Post by Velocomp »

It looks like the two 24km files you uploaded are from the same ride, except that one has been processed mathematically with Isaac.

What kind of speed sensor are you using?

When Isaac processes files, minor differences (which is what you have) can occur.

There are some ENORMOUS headwinds on your ride; are these real?

Your mount location looks fine.
John Hamann
gjmeer
Posts: 6
Joined: Sun Jun 16, 2019 7:30 am

Re: Different calibrations, please check.

Post by gjmeer »

Thanks for you reply.

It's true that the two files are from the same ride. For the comparison, I was curious about the impact of the two calibrations.
I can also imagine small differences, but I think the differences are quite large. Or am I wrong?

I use a magnetless Wahoo speed sensor and also a Wahoo magnetless cadence sensor.

What about the the wind. There was a NNW wind of around 10 mph / 16 kmph. from km 11 I drove straight to the Northeast, from km14.5 to the northwest and from km 16 to the north. In this section there was a headwind / crosswind, but 3 bft is not huge.
https://www.wunderground.com/history/da ... /2019-6-15

Today made a new ride based on the Cal Ride. Here the values seem reasonable, although I have the impression that during driving at low intensity values are displayed too low and at low intensity too high values. Is that true, or am I wrong?

Thank you in advance.
Attachments
PowerPod_2019_06_18_1223_47_km.ibr
(297.12 KiB) Downloaded 121 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Different calibrations, please check.

Post by Velocomp »

The differences aren't large, in my opinion. What is most important is that you use the same settings, for consistency.

Wahoo sensors are not as good as Garmin sensors; Wahoo sensors have speed spikes. You can see this if you set your filtering to zero. It's not fatal, however...

I think your ride file looks fine!
John Hamann
gjmeer
Posts: 6
Joined: Sun Jun 16, 2019 7:30 am

Re: Different calibrations, please check.

Post by gjmeer »

Bedankt voor je reactie.

Ik merkte de pieken in snelheid niet op. Ik zal zoeken naar een Garmin-sensor en dan een nieuwe kalibratie uitvoeren. Van daaruit ga ik ervan uit dat de rest correct is.

Dank voor de moeite van het meekijken.
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