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Is there a limit to how low a head or back can be to be beneficial? For aerodynmic purposes, is a horizontal back ideal, or would being lower than that do any good? I suppose there might be some benefit to having the head lower, even if the back is then sloping down. On the other hand, I can envision a back sloping down to the front might actually increase frontal area compared to horizontal, or at least not improve it. Has anyone seen any testing on this? Thanks.
 

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Fixed said:
Is there a limit to how low a head or back can be to be beneficial? For aerodynmic purposes, is a horizontal back ideal, or would being lower than that do any good? I suppose there might be some benefit to having the head lower, even if the back is then sloping down. On the other hand, I can envision a back sloping down to the front might actually increase frontal area compared to horizontal, or at least not improve it. Has anyone seen any testing on this? Thanks.
http://forum.slowtwitch.com/cgi-bin...romion;guest=38153148&t=search_engine#1893722
 

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Time trialling or riding? If you get really aero, you will probably lose power, but the aero advantage out weighs the power loss (to a point). Also, the more aero you get, the less comfortable you will find it.

edited for a slight clarification.
 

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Without a wind tunnel, its hard to make generalizations, as individual differences between riders can make a big difference in aerodynamics. One rider might make great gains with a really low head while another won't necessarily.
 

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kbiker3111 said:
Without a wind tunnel, its hard to make generalizations, as individual differences between riders can make a big difference in aerodynamics. One rider might make great gains with a really low head while another won't necessarily.
As time has passed and more wind tunnel data has been taken, this has been shown to work remarkably well. A search on neandrathal [sic] position will bring up later discussions.
http://groups.google.com/group/rec....athal+position+coggan&rnum=1#46e0c0aabed40c18


coggan

Not to be disagreeable, but I disagree. If my goal were to set myself up
in an aero position with minimal drag and I didn't have access to a wind
tunnel, I'd just drop the elbow pads far enough down below the saddle
that my shoulders (acromion process) were within a couple of inches of
being level with my hips (head of greater trochanter), move the elbow
pads in to where my arms were as narrow or perhaps narrower than my
thighs when viewed from the front, tilt the aero bars up
ever-so-slightly, and keep my head down. I'd then go out and ride the
bike - hard - in that position and see how far foward (and thus up) I
needed to move the saddle to where my thigh-torso angle was similar to
the "working position" on my road bike. I'd then ride the TT bike for at
least one hour - hard! - each week for at least 6 weeks before any race.
Sounds crude, I know, but for a flat TT this neandrathal approach will
probably get you to within about 1 km/h of your maximal speed.

Now, the caveats:

1) achieving such a position will, as has been discussed, probably
require special equipment, e.g., a frame with TT-specifc geometry, or at
the very least a down-angled stem/forward seatpost. The latter
approach is okay as long as you don't fall off your bike as a result of
having too much weight on the front wheel.

2) the above isn't necessarily the fastest position for a rolling or
hilly course, or at least may not be unless you devote more time
learning how to go fast in such a position.

3) gaining that extra 1 km/h will probably require spending time in the
wind tunnel further refining your position.

4) use of a power meter such as an SRM or Tune to try to refine your
aero position can be entertaining, but unless you have access to an
indoor velodrome probably won't help you go any faster than just
following the advice of somebody with a well-trained eye (like John
Cobb), or simply copying the positions of athletes known to have low
drag. OTOH, having the power data can be very useful for training
purposes, and for pacing during TTs.
 
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