Observations from today's ride (aerodynamics related content)

[93KgBike]

Originally Posted by pncguy

looking at your hr, my heart just exploded. I don't like being 50.

+1!

[kppolich]

here is a fantastic website for after you crawl deeper down the Aero rabbit hole. You will need to find the air density of where you are riding, after that look how much a decrease in drag speeds you up.


https://www.gribble.org/cycling/power_v_speed.html

[RyanH]

I wrote a pretty extensive series on doing aero testing on Weight Weenies:

http://weightweenies.starbike.com/fo...c.php?t=139992

[fa63]

^^ I remember that (I am a member on WW as well). That was a valiant effort; this is nothing like that

[Web1111a]

Where did you do this ride

Looking for new courses in Atlanta area

[fa63]

We just did laps on Columns Drive. Not particularly exciting to ride on, but good for intervals and such. To check out group rides around town, this is the best source I have found:

www.sadlebred.com/rides

[RyanH]

I'll post this here for general knowledge since someone asked me in a PM if I had any pointers on aero testing. Here's what I gathered through some trials and tribulations over roughly three months of aero testing:

• You absolutely need to use a GSC-10 or similar speed sensor with an accurate wheel rollout. GPS is too "dirty." I did 15 runs with GPS and had to scrap them all since I was getting way too much variance.
• You need to pedal the entire time. PMs for some reason keep sending data for ~1.5s even though you're producing zero power so this throws off the CdA.
• Can't touch your brakes and want to avoid riding near cars.
• A course with elevation change is good but not necessary.
• If there's elevation change, as little wind as 2mph on the uphill side (headwind) can significantly throw off your data.
• Since this is "real world" testing, don't just do something once and assume that's your CdA for that setup. I'd suggest repeating at least 3 times to ensure consistency among those data points, but preferrably 5 times.
• Make sure you get a local weather station point that accurately reflects your conditions. At the Rose Bowl, I had to buy a Kestrel to identify which station gave me correct info since the ones surround the Bowl varied by up to 10 degrees.
• Sorry Stages users (and other 1 sided PMs), your data is not consistent enough for this type of testing.
• Keep your position on the bike as consistent as possible. I focused on maintaining my "normal" riding position.
• I did my testing at a constant 240w but that's not necessary either and mixing wattage supposedly helps tease out the rolling resistance. If I were doing it again though, I'd still do a constant 240w. The benefit of it (in my mind) is that I can see if any laps are skewed if they are much faster or slower than others.

That's all that comes to mind at the moment.

[ojingoh]

Originally Posted by pncguy

Looking at your HR, my heart just exploded. I don't like being 50.

Agree- That's damn impressive.