From Good to Great - Wish List

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RolfK
Posts: 26
Joined: Fri Nov 02, 2018 4:47 am

From Good to Great - Wish List

Post by RolfK »

Firstly, this is almost avantgarde, to be able to, as an ordinary masters time trialist, work with in-the-field, real time CdA analysis. It is huge that you have made this possible and affordable. So, please: the following is meant to be constructive, to help improve the AeroPod. It's already good, as it is.

I have two areas where I think improvements could be made relatively easily; data smoothing and data resolution.

Both areas may get improved automatically, when the official CdA Ant+ profile is released. Garmin and Wahoo and others will probably implement CdA data fields similar to their power data fields, with no smoothing as well as rolling 3s, 30s etc. and lap averages. But, this may take a while. I personally don't think the profile will get released before Garmin has their own CdA measuring device ready for the market.

So, in the meantime...

1) Data smoothing
I firmly believe that all smoothing should be done solely for display and analysis purposes, and that recorded files should contain the raw, second-by-second CdA values.

Would it be possible to make CdA smoothing optional in the AeroPod, just like power smoothing is? To move smoothing to the Garmin CIQ App - and with a shorter rolling window?

As it is, changes of position are manifested very slowly in the CdA numbers. In this example, transitioning from riding around in the base bar to riding in the extensions takes almost the full 90 seconds to manifest itself. Obviously, for testing it's easy to work around, but for real time feedback while racing (in events where that will be legal), the time lag is too big.
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2) Data Resolution
As it is, the resolution is 0.004 CdA units. What will the resolution be, when the switch is made from transmitting HR values to transmitting true CdA values? 0.0001? 0.001?

In the mean time, would changing the scaling to improve resolution be possible? right now AeroPod can handle CdA values from 0 to (4 * 220) / 1000 = 0.88 (I'm assuming that Garmins don't permit HR's above 220). That is a very wide range. The resolution could be doubled by calculating CdA as (HR + 75) * 2 / 1000, if one could live with a CdA measuring range from 0.15 to 0.59. I think that most users could live with that range.

Thank you :)
RolfK
Posts: 26
Joined: Fri Nov 02, 2018 4:47 am

Re: From Good to Great - Wish List

Post by RolfK »

Just to elaborate on the data resolution point: A reduction in CdA of .004 from, say, .254 to .250 corresponds roughly to an efficiency gain of 4 watts when riding in the 40-45 km/h range.
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Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: From Good to Great - Wish List

Post by Velocomp »

From our instructions (page 28):

'A “rule of thumb” is that a CdA change of .001 reflects a 1 watt difference between applied and opposing power readings. This is a small difference in power readings.'

So, we very much agree with your post!
John Hamann
RolfK
Posts: 26
Joined: Fri Nov 02, 2018 4:47 am

Re: From Good to Great - Wish List

Post by RolfK »

Yes, the physics are what they are. A .001 resolution would be perfect, .004 is a little coarse.

I hope that the ideas presented above are useful.
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