Check calibration ride

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sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Check calibration ride

Post by sjeffrey »

Hi,
I'm on my 2nd year with the Powerpod. I always had issues calibrating it correctly but this winter I got some Assioma power pedals. I'm hoping to calibrate the Powerpod correctly by using DFPM and once setup my commuter bike can go back to it's old pedals and I'll leave the Powerpod on that bike permanently.

I have did a calibration ride last night that looks pretty close to the DFPM however, when I do a check calibration and allow to use DFPM data the power drops well below the original power data and the DFPM data.

I attached my calibration ride and I was hoping someone could review it.
iBike_04_30_2018_1817_2_Miles_CalRide.ibr
(44.79 KiB) Downloaded 185 times
Thanks!
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Check calibration ride

Post by Velocomp »

Please post a ride file from AFTER your calibration ride.

Calibration rides should not be used to tweak profiles, particularly with a DFPM.
John Hamann
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

Sorry about that. I didn't realize it couldn't be off the calibration ride.
Here's today's commute using the profile.

Stephane
Attachments
iBike_05_02_2018_1614_9_Miles.ibr
(133.63 KiB) Downloaded 179 times
iBike_05_02_2018_0734_9_Miles.ibr
(107.04 KiB) Downloaded 197 times
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

Bump :)
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Check calibration ride

Post by Velocomp »

Your two ride files are quite different in wind speed. I don't know which one to "believe".

Also, your CdA is a number that is appropriate for a TT bike...not a commuter bike.

Finally, your Crr is high, but if you're on a commuter bike it probably is OK.

Please do a new calibration ride, then post the ride file afterwards.

We will sort this out!
John Hamann
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

Believe me, the difference in wind was real!
So do you want me to do new calibration ride and a ride using the new calibrated profile and then post both?
My commuter is still a road bike so regular hoods and drops handlebars.
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Check calibration ride

Post by Velocomp »

Ahh...if your commuter bike is a road bike, then both CdA and Crr are wrong.

Yes, please do a new calibration, and post the ride file AFTER the calibration.
John Hamann
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

Here's a ride after a new calibration.
What's interesting is that the DFPM average is much lower than it should be. Isaac reports average of 113 while Strava and Golden Cheetah report an average of 155. The powermeter I am using are the Assioma pedals. They should be well calibrated as the power reading matches almost exactly the power calculation from my Kickr.

I appreciate the help,
Thanks

Stephane
Attachments
iBike_05_09_2018_0743_2_Miles_CalRide.ibr
(40.81 KiB) Downloaded 158 times
iBike_05_09_2018_0752_8_Miles.ibr
(153.92 KiB) Downloaded 163 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Check calibration ride

Post by Velocomp »

This ride is very close.

You adjusted CdA up to .363...much better for your road bike.

PP watts are 119...DFPM watts 113. I don't know where your 155 number comes from.
John Hamann
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

The 155 comes from either uploading the pedal power meter data to my Wahoo Bolt to Strava or taking the FIT file and importing into Golden Cheetah. Even taking every recorded entry from that FIT file and dumping the power values in Excel gives me an average of 150 watts. 113 just sounds very low compared to my usual rides. With average heart rate of 133 my power output should be higher.

There's a thread about Wahoo Elemnt recording bad average powerdata here: https://groups.google.com/forum/#!msg/w ... i6EzU0AwAJ
So perhaps the issue is with how the Assioma pedals report the data...

What I'll do is I'll keep the Assioma pedals on the bike and record using Garmin watch to see if I get same as Powerpod or not.
sjeffrey
Posts: 17
Joined: Mon Apr 10, 2017 9:15 pm

Re: Check calibration ride

Post by sjeffrey »

Here's the link to Strava in case it helps
https://www.strava.com/activities/1559907553

This ride includes the the time I spent doing the PP calibration. Obviously the ride was recorded using the Assioma pedals. The 4km mark is where the PP would have started to record actual ride. Selecting only the ride after the first 4km gives me an even higher average of 169 watts.
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