Real World Aero Testing via Chung Method - Data Thread

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RyanH
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by RyanH

I'm regretting this already, but I'm committing to spending 3 days a week doing laps around the Rose Bowl at 240 watts (tempo pace) for an hour using various bikes and wheelsets. The goal is to get 5-10 samples of each configuration as a baseline. From there, I have a few more ideas which I'll discuss later. I'll put together a spreadsheet in Google Docs and update this thread as I go.

There's others on here who have done similar tests, and I think it'd be useful to post that information in a single thread.

For my testing:

Course:
3.1 mile loop. West side is a climb and east side is a negative grade. 112ft of elevation per lap.
https://www.strava.com/segments/12466587

Testing Constants:
Position: Hoods
Bottles: Front bottle, rear will have fred can with tire
Clothing: Kask Protone Helmet, Rapha Core Jersey (uggh...poor choice...may switch to pro team if it doesn't skew results), Rapha Pro Team Bibs, Giro Empire Shoes
Powermeter: I'll move the Quarq from bike to bike to get consistent results.

Equipment to be tested:
Bikes: Fuji Altamira, Cervelo R5ca and Scott Foil 2016
Wheelsets: Shimano RS11 (box section), Reynolds 32's, Reynolds RZRs, Zipp 404's
Tires: Veloflex Carbon, Veloflex Record, Vittoria Evo Pave 27mm and Vittoria G+ 23mm tubulars.

Resources
Air Density Calculator by Steve Gribble
Power Models by CyclingPowerLab
Golden Cheetah

Day 1: Fuji Altamira with Reynolds Thirty-Two's and Vittoria Evo Pave 27mm Tubulars
Tire Pressure: 70F/70R
Beginning Temp: 78*F
Ending Temp: 84*F
Wind: 0-3mph SW (flag was half value which seems to be more than the recorded weather's 0-3
Avg HR: 152 bpm
Avg Speed: 21.8
Distance Covered: 21.8mi
Estimated CdA: 0.3687
Ride Data (Strava)

Notes: First 10 minutes was too fast, went out at 250w. The heat bumped my HR up to 160 on the last laps. I'm glad I decided to not do these at threshold. I'm tired and sore from yesterday, this week is going to suck.

Day #1 Test Setup:

This should represent the 2nd most unaero setup that I have (the Fuji with box sections will be the most unaero). The Fuji's HT is thick and the downtube is enormous. Round bars to round things out.

Image

Day #1 Chung Method Aero Analysis
Image

Note: Updated 6-28-2016 with revised Aerolab analysis
Last edited by RyanH on Fri Jul 01, 2016 10:07 pm, edited 4 times in total.

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dudemanppl
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by dudemanppl

I like this a lot. I see you ended up getting those 404s!

justkeepedaling
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by justkeepedaling

No, stop your marketing, you must be someone the industry paid off. There is no such thing as aero benefit.

Just kidding ;)

junchen
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by junchen

Tks for sharing. Had to Google what the chung method is... Interesting to see the results.

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BRM
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by BRM

justkeepedaling wrote:No, stop your marketing, you must be someone the industry paid off. There is no such thing as aero benefit.

Just kidding ;)
Noone said on this forum these words. You haven't understood anything of former discussions. You need to rape words and put them in a new setting trying to get a point. It says something about your intelligence level.

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BRM
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by BRM

RyanH wrote:This should represent the 2nd most unaero setup that I have (the Fuji with box sections will be the most unaero). The Fuji's HT is thick and the downtube is enormous. Round bars to round things out.

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For your information:
Round tubes are already reasonable Aero.
The thick headtube and the big downtube on its own, doesn't say anything about the Aero level of the total bike.

cobrakai
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by cobrakai

Thanks for sharing, looking forward to the data.

@BRM round tubes are horribly aero. Pretty much the only thing worse would be something square/rectangular.
https://en.wikipedia.org/wiki/Drag_coefficient

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BRM
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by BRM

Wrong interpretations of figures.
A road race bike frame with round tubes is reasonable Aero, not horrible.
Important to understand is that we are talking about a bike frame and not just about some static models on a wiki page.

People need to stop to stare autistic to figures without the meaning in real life.
Try to conceive the basics.
A bike frame of mainly roundtubes is already reasonable Aero and not total negative as some believe.
And sure a bike frame with more aeroshaped tubes is more Aero than the round tubed frame and although the difference in figures can look big, the reality is that it is not a big issue. Because the frame is only a small percentage of the total (you and your bike and equipment together)
Besides that in the real world there are other parameters that has influence on Aero.
The total win for you as a road race biker is nihil.

And there are other parameters that has influence on speed with greater importance and impact than that minimal Aero effect benefit.
Then at last you need to understand that a road race is build up of many stages where speed and power fluctuate many times.

You also have people that can discuss endlessly the drag of chainlubes.
Same thing, it plays no single role. When you set it off to the power you generate with your legs.
But yeah on paper it willlook as an enormous difference . . . .

Set the things in the right proportions.

RyanH
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by RyanH

Well, the goal is to translate those assertions into observed data. Ultimately, I want to test the benefits within a pelotón and then test to see the impact on a race like finish.

An idea would be, after quantifying the difference within the pelotón of an aero and non aero frame, to use the delta and do multiple two hour tempo runs and finish with a race effort climb to see if, for example, 14w saved over two hours has a meaningful impact on simulated finishing efforts.

Well, it's 530am and almost time to go for a ride.

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Marin
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by Marin

Are you just reading the power number on your computer or are you crunching numbers afterwards too (á la Chung)?

If you're only doing the former, I don't think your data will have a lot of meaning :(

RyanH
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by RyanH

I'm going to to put the numbers through the Chung method calculator later today, is there something else I should be doing, welcoming feedback:

http://www.cyclingpowerlab.com/CdAEstimation.aspx

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cobrakai
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by cobrakai

Golden cheetah also has the chung method pre-programmed into it if you would rather use that.

RyanH
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by RyanH

Day 2: Fuji Altamira with Reynolds RZR 46T and Veloflex Carbon 23mm Tubulars
Tire Pressure: 100F/100R
Beginning Temp: 70*F
Ending Temp: 74*F
Wind: 0-3mph SW (observed wind was zero value flag to 3/4 value flag)
Avg HR: 150 bpm
Avg Speed: 21.
Distance Covered: 21.856 mi
Estimated CdA: 0.3562
Ride Data (Strava)

Notes: Tires have sealant in them. 100 psi is unpleasant.

Day #2 Test Setup:

Image

Day #2 Chung Method Aero Analysis

Image

Atmospherics (end of session)
Image

Comments:
I was expecting a bigger difference. This could be well within the margin of error, we'll have to see as I perform more runs. Golden Cheetah doesn't let me modify the temp, so I'm not sure if it's taking into account the temperature recorded or not. I also don't know the Crr's, so I can only keep that constant at 0.004013.

Note: Updated 2016-06-28 with weather data and Aerolab analysis
Last edited by RyanH on Wed Jun 29, 2016 5:57 am, edited 1 time in total.

cobrakai
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by cobrakai

Hm I would expect that Crr would change as you change tires. I haven't looked at the Chung protocol in a while but I thought that it had a provision to estimate Crr in addition to CdA since you have a known elevation profile.

RyanH
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by RyanH

If there is, let me know as I agree, Crr can and should play an influence. I'll probably glue up the 32's and the 404's with Veloflex Carbons as well to hopefully control for Crr to some degree.

Anything else that I should be controlling for and/or trying to observe and record? The fitting of the line on Golden Cheetah seems prone to error but cyclingpowerlab doesn't take into account course profile in their calculator so I think Goldencheetah should be more accurate. So, suggestions would be appreciated.

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