On Wed, 15 Jun 2005 09:43:02 +0200, "Robert Chung"
<
[email protected]> wrote:
>[email protected] wrote:
>
>> Climbing, from the side.
>
>Have you checked out http://grahamwatson.com/ ?
>Or possibly, since you're interested in climbing,
>http://www.littlechainring.com/
Dear Robert,
Aha!
In this picture . . .
http://grahamwatson.com/news/images/2005/17may7.jpg
.. . . the arms of both riders are only slightly curved,
their heads are up, and they aren't twisting or dropping a
shoulder, so they look fairly relaxed for a standing climb.
A vertical line dropped from either rider's ear will fall
between the front axle and the intersection of the fork and
tire. (The right edge of the picture makes this very clear
on the far rider, whose face is half cropped.)
The same ear position is shown in this picture, which is
even better:
http://www.littlechainring.com/12 lance climb bw.jpg
Look at all those lines on the building and crowd rails in
the background beyond Lance! The camera angle isn't perfect,
but it's as close as we're likely to get to a grid in an
impromptu picture.
Again, a true vertical line (the picture is a bit tilted, so
you have to use the building beyond him) dropped from his
ear appears to descend between his front axle and the
intersection of the fork and tire.
The ear business seems to work, even though Lance is
crouching more, his head is down, and his arms are bent
further than the more relaxed riders standing in the other
picture.)
The headless rider just ahead of Lance is interesting, too.
His right leg is almost fully straightened near the bottom
of the downstroke--and look how far forward he's bent at
this moment and how his body is twisted slightly to his
right, following his descending right foot. His right elbow
is bent back behind the leading edge of his forward-bent
left thigh.
The faint vertical line on the wall beyond Lance is helpful.
A ruler laid along it will touch the back of each of Lance's
elbows, the back of his bent right knee, and the middle of
his left ankle on the downstroke.
His front axle is nicely centered against the bottom of the
crowd railing and aligned with an upright bar--the
background forms a protractor for his front wheel.
Raise a vertical line from the bottom bracket--lay a ruler
parallel to that helpful faint line on the wall.
About 90% of Lance's body is ahead of the bottom bracket.
Only his right foot, part of his lower right leg, and part
of his butt are behind a true vertical line rising from the
bottom bracket.
Do the same thing with the headless rider ahead of Lance,
and you get roughly the same result--practically all of the
rider is forward of a true vertical line rising from the
bottom bracket.
Of course, the bottom bracket is not the true center of
mechanical action in this situation. Lance's foot will
rotate forward as well as downward, bringing it more under
his center of mass about half-way down, and then retreat
backward behind him for the rest of the downstroke.
But it looks to me as if the riders are leaning well forward
onto the bars and curling from side to side, with one elbow
following the foot on each downstroke.
They may be pulling down and toward the downstroke pedal
with one arm, but I think that they must also be pulling the
other way with the other arm to keep their balance. The
angles make it look as if they're doing a lot of forward
leaning on the handlebars--mimic that position while
standing on a scale and leaning against a railing, and
you'll find it hard to pull down enough to make the scale
read your original weight.
I'm starting to think that the real advantage of standing is
not so much "weight on the pedal" as improving the posture
for exerting greater force with the leg muscles themselves.
When standing, the thigh angle is much closer to being
straight relative to the body and has a much better
mechanical advantage--it's closer to the natural human
standing posture than our usual seated position, where our
thighs come up much farther and end up at their feeblest
angle.
Notice how much harder we strain as our thighs start coming
up toward our chests--we can stand easily with our legs bent
only slightly, but once our knees come up to roughly 90
degrees relative to our torsos, things get harder and
harder. Our legs work best when dangling mostly below us.)
Here's the same picture with three black lines that I think
are roughly true vertical, showing how far forward the rider
is leaning:
http://home.comcast.net/~carlfogel/download/lanceclimb.jpg
The real advantage of standing up seems to be how far away
it puts the knees from the chest, not how much weight it
puts above the bottom bracket--the riders seem to be leaning
much farther forward than a "full-weight-on-the-pedal"
theory would allow.
Carl Fogel
