Struggling to tweak CRR/ high CDA

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mareng
Posts: 3
Joined: Sun Jun 02, 2019 4:45 am

Struggling to tweak CRR/ high CDA

Post by mareng »

I performed the attached ride and ended up with unexpectedly high CDA (Was particularly interested in the first 2 efforts).

The road surface is fairly rough, so I suspect CRR set too low. When I use the "Tweak CDA, CRR ..." under the analyze menu and save the file (attached), then go back to the "Analyze CDA" I get the exact same CDA numbers - any idea what I am doing wrong?

Thanks
Attachments
iBike_08_07_2019_1841_21_Miles.ibr
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Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Struggling to tweak CRR/ high CDA

Post by Velocomp »

There is a bug in Isaac we are working on. In the mean time, here's how to work-around it:

1) Adjust your Crr value with the "Analyze/Tweak CdA-Crr" command

2) To see its effect on CdA, next use the command "Tools/Power Meter Comparison". For one of the fields presented, select "CdA". You'll see a graphical representation of CdA that is based on the tweaked value of Crr

3) Note that the drag-drop CdA averaging feature does not work at this time in this window.

4) If you want to measure CdA for a section of the ride, you'll need to highlight that section in the main window. Click the View DFPM box to compare watts between AP and DFPM readings. Then, manually adjust CdA in the "Analyze/Tweak CdA" window until you get AP and DFPM watts the same.

We are working on automating the above process...
John Hamann
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