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Hmmm, good point. Considering the reduced frontal area of the test setup (no shoulders, handlebars, back), that lower body shape must have a terrible Cd compared to a real cyclist to arrive at that CdA. That would also exacerbate the effect of poking that shape up 4mm into the wind.Don't forget the wheels used on that setup...not exactly a deep front and a disc ;-)
I'd expect a "full" cyclist on that road setup to have a total CdA closer to .350 m^2 than .250 m^2. The CdA that AC was referring to was a "full aero" TT-type CdA.
but doesn't a CdA of .234 seem crazy-high for half of a body??? That cut-off torso must have some horrible drag (and is quite freaky-looking)
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Anyway, I do believe that there must be some postitive aero effect of lowering a cyclist on a bike, but I'm very suspicious of SpeedPlay's rational for removing parts of the cyclist and bike to remove "extraneous hardware". I certainly don't consider my heart, lungs, and head to be "extranous" :-) I'd suspect that the numbers just turned out better this way.
I don't think it's so much about lowering the body relative to the bike or pedals, but more about removing the surface area of the front of the spacer out of the air stream.
It's really about reducing the "A" part of the CdA.
Well...what's better, a surface being hit with "messy" air, or a slightly smaller surface being hit with "messy" air?
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