Trouble with Newton Setup (user error?)

Trouble with Newton Setup (user error?)

Postby KLP » Sat Oct 14, 2017 5:37 pm

Disclaimer: I am relatively new to cycling (2,3 years) and only started structured training with a power meter this June. Newton has been a great help but I'd like to start fine tuning some of my profiles to get the most out of it that I can.

I'm not sure what to make of this FTP ride. I was riding around a track and the winds were very strong. The power seems very low given my effort, and that 2 days after I averaged the same power while climbing hills; the second ride took less out of me. I think my profile is incorrectly configured (wind resistance constants) and I'm getting low power readouts during windy days, which are quite common here. I've not found a way to do coast down calibration (my device can't access setup screen), and even if I did I'm not sure there would be a calm day without winds to do them! Note: the FTP ride was right after a new profile reset & calibration

How can I accurately fine tune my profile and drag constants? Based on an old post of John's I tried calculating power on bikecalculator.com but couldn't get it near what my Newton reports for the ride. Would someone mind looking at the attached ride file?
Attachments
iBike_10_03_2017_1936_7_Miles.ibr
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KLP
 
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Re: Trouble with Newton Setup (user error?)

Postby Velocomp » Sat Oct 14, 2017 6:51 pm

I think you are fine...

1) I have a "rule of thumb" 20/20 approximation: on the flats, at 20 mph, you'll need about 200W

2) To use bike calculator you need to pick a place where conditions are constant. I did this for the place shown; your Newton measured 195W and bike calculator, 201W

3) At the end of your FTP test you had some "gas" left in the tank. You probably could have biked with more power during your test... :D
Attachments
Screen Shot 2017-10-14 at 6.42.29 PM.png
Screen Shot 2017-10-14 at 6.42.29 PM.png (1.02 MiB) Viewed 156 times
Screen Shot 2017-10-14 at 6.44.55 PM.png
Screen Shot 2017-10-14 at 6.44.55 PM.png (671.37 KiB) Viewed 156 times
John Hamann
Velocomp
Velocomp CEO
 
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Re: Trouble with Newton Setup (user error?)

Postby KLP » Sat Oct 14, 2017 8:26 pm

Ah, thanks! Looks like I entered the incorrect wind speed (average ground speed makes sense when I think about it).

I could work on pacing these, always seem to finish with some gas left. Time to get back out there! Many thanks
KLP
 
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