I'm Confused (As Per Usual)

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AN2019
Posts: 43
Joined: Sat Oct 05, 2019 6:31 pm

I'm Confused (As Per Usual)

Post by AN2019 »

So,

Decided to do a Profile 4 calibration ride. I then decided to test positions on a closed, 3.4 mile loop. I wanted to compare riding on the tops versus the drops. I did 4 loops on the tops and 3 loops on the drops. Unfortunately, I had auto-lap on for the first lap and I got a 3 second "lap." Attached are my files. I can't make heads or tails of it (what I got doesn't make sense; seemed to suggest no real difference between drops and hoods). A few notes:

1) I put on Turbo Cotton tires and latex tubes today. They have very low rolling resistance apparently. As per usual, my initial setup decided to put .006 for my RR, which is far from correct. I think it's more like .0033.

2) The weather deteriorated a bit over the course of the test. It started sprinkling rain a little and seemed to get a little windier during the drops segments.

3) I did not hold my power consistently. Treated it like a tempo ride and was feeling a bit warmed up the further I got. The power from my DFPM ranged from 228 normalized to 293 normalized on the final lap.

4) It is not a flat loop, but as flat as it gets here (85 feet per lap, 700ish for the test).

Files attached.
AN2019
Posts: 43
Joined: Sat Oct 05, 2019 6:31 pm

Re: I'm Confused (As Per Usual)

Post by AN2019 »

Files.
Attachments
Andy comp.zip
(369.25 KiB) Downloaded 4 times
Velocomp
Velocomp CEO
Posts: 7583
Joined: Fri Jan 11, 2008 8:43 am

Re: I'm Confused (As Per Usual)

Post by Velocomp »

I took your ride files and consolidated them into an overall ride file using the File/Merge command. This allows me to see the overall pattern of your testing and your test results:
Screen Shot 2022-07-30 at 5.01.07 PM.png
Screen Shot 2022-07-30 at 5.01.07 PM.png (347.23 KiB) Viewed 126 times
Not only does your course have a fair number of elevation changes, but you also appear to be making some sharp turns, specifically where your speed and cadence drops in a place where there is a 6% grade
Screen Shot 2022-07-30 at 5.14.13 PM.png
Screen Shot 2022-07-30 at 5.14.13 PM.png (252.52 KiB) Viewed 126 times
Overall, I think there are far too many variations in your bike speed, power, and cadence to get repeatable results. Deteriorating conditions do not appear to be an issue in your ride file.

Your CdA is shown in the HR data field for 10 sec at the end of each lap: CdA = HR +180

Here is what I get for your CdA values

Hoods:

0.247
0.221
0.232
0.24

Drops

0.248
0.228
0.247

As a rule of thumb I throw out the first lap of any new measurement: this would be lap 1 and 4 for you. So, you have 3 laps for Hoods and 2. laps for drops.

I would repeat these tests, trying to hold power levels and cadence constant (non-zero), and do at least 5 laps of each configuration.
Attachments
Andy_combined_07_29_2022_1632_26_Miles.ibr
(316.09 KiB) Downloaded 4 times
John Hamann
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