Questions to results from aero testing

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aeropod.user
Posts: 20
Joined: Sat Jul 20, 2019 2:08 am

Questions to results from aero testing

Post by aeropod.user »

Hello John,

today in aero tests I wanted to compare two TT helmets (Kask Mistral and Giro Aerohead) plus check how my CdA changes when I ride with arm cups narrow or wide with each helmet. I performed 8 tests: 2 for each helmet with arm cups narrow / wide configuration. Every test was out and back ride to the same place, I tried to keep power on similar level between test runs. Aeropod position remained unchanged, the device was set to profile 3 and calibrated before the tests.

I attach results to this post if you want to look at details. Attachment contains both calibration ride, ride file downloaded from Aeropod and test runs separated to separate files. I also created Excel file with comparison of everything.

I have following questions to this:
1) For each test run I note 3 different values in Isaac:
* as it was recorded,
* as it is after applying Analyse->Analyze Route (I kept the selection for OUT or BACK part unchanged to make sure that I execute Tools->CdA Analysis on Selection against exactly the same part of given ride),
* and as comes from HR channel with HR*4/1000 formula.
Which one should I trust?
2) The differences between recorded values and those after Analyse->Analyze Route are not consistent for every OUT / BACK ride, although the same calibration of the device and the same start/finish of the ride. Please, see at the bottom of the Excel file - I gathered all of them there. Is it normal?
3) I see that Aeropod shows in Isaac much higher DFPM power values than my Garmin device recorded. As an example I attached screenshots from Isaac and Strava for the same run. Isaac shows 451,9W, Strava shows 374W. I can see 374W also in GoldenCheetah. Is it normal? Is there any option in Isaac to see real DFPM power readings?
4) Last but not least: is my reasoning right that Kask Mistral in my case is faster with narrow arm pads, and Giro Aerohead is faster with wide arm pads?

Thank you in advance for your answers.

Regads,
Bartosz
Attachments
TestRun1-Power_Strava.PNG
TestRun1-Power_Strava.PNG (61.9 KiB) Viewed 2001 times
TestRun1-Power_Isaac.PNG
TestRun1-Power_Isaac.PNG (143.27 KiB) Viewed 2001 times
20200802_aerotests_Mistral_Aerohead.zip
(644.83 KiB) Downloaded 179 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Questions to results from aero testing

Post by Velocomp »

Honestly, this post is too complicated to respond to:

1) Your test method is unclear

2) For the testing you're doing, you should have used profile 4, not profile 3. Please read AeroPod documentation

3) It's difficult to figure out where each test occurred in the master file. When you separate out the big file into smaller ones this makes analysis more difficult

4) I cannot tell anything from your Strava/Isaac comparison. Where is this in the ride file?

I am reluctant to draw any conclusions regarding equipment comparison. That's mostly because I don't understand your test method and your data.
John Hamann
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