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wafflycat said:

Quoted message said:

I think I could use my large rear and ample bosums giving too high a
centre of gravity to be stable as an excuse :-)

and [email hidden] thunk:

Quoted message said:

shouldn't a higher CoG make it easier to balance?

Only if the weight is easy to move around in a controlled manner in
order to restore balance when one starts to fall. The large rear would
be plonked firmly on the seat and would be, for all intents and
purposes, an immovable object. The ample bosums could be moved along
with the rest of the upper body in order to reposition the centre of
mass, but I wonder of the bosums may follow slightly after the rest of
the upper body, then continue moving after the rest of the body has
stopped, causing a degree of unpredictability in the redistribution of mass.

Sorry Helen ;-)

--
Danny Colyer <URL:http://www.colyer.plus.com/danny/>
"He who dares not offend cannot be honest." - Thomas Paine

Jim Price said:

Try balancing a pencil on it's end on your finger, then try something
similar but about a metre long. I've tried this theory out on two
significantly different heights of unicycle - the taller one was much
easier to balance on as it seemed like you had much more time between
when you noticed it starting to topple and it getting beyond what you
could recover from.

Stevie's right if you're on a trike, though. On one or two wheels, a
higher CoG makes balancing easier, but once you have a stable base then
a lower CoG helps.

As for the pencil argument, there's a good reason why it's forbidden to
use a devil stick (about 26" long) instead of a club (about 20" long) in
face balancing competitions at juggling conventions. Balancing a devil
stick on your nose is really easy. Balancing a club is easy enough,
with practice. It took me a _long_ time to learn to balance a pencil on
my nose, and I never got really good at it.

And taller unicycles only get easier until you reach the point where
it's too heavy to control easily, or until the rider's fear of pain
makes it impossible to move away from the wall. IME a 6' giraffe is
easy to ride, but I'm far too much of a coward to go anywhere on a 9'.

--
Danny Colyer <URL:http://www.colyer.plus.com/danny/>
"He who dares not offend cannot be honest." - Thomas Paine

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

I always thought a _lower_ centre of gravity gave you better balance.

<snip>

Quoted message said:

If your COG is 25cm above ground, and you lean 5 degrees, your COG is
2.2cm outside your balance line - but if your COG is 1m above ground,
and you lean 5 degrees, your COG moves to 8.8cm outside your balance
line. This means that you are inherently less stable - factor in the
leverage effect that a higher COG has and you get a much greater pull
downwards.

But look at this another way; if you're 25cm above the ground, moving
your COG a mere 2.2 cm outside your balance line gives you a lean of 5
degrees, whereas at 1m above ground, moving your COG 2.2 cm only gives
you a lean angle of 1.26 degrees, which is easier to regain your balance
from than a 5 degree lean.

Colin
--

Coincidence is the alibi of the Gods

"Danny Colyer" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

wafflycat said:

Quoted message said:

I think I could use my large rear and ample bosums giving too high a
centre of gravity to be stable as an excuse :-)

and [email hidden] thunk:

Quoted message said:

shouldn't a higher CoG make it easier to balance?

Only if the weight is easy to move around in a controlled manner in order
to restore balance when one starts to fall. The large rear would be
plonked firmly on the seat and would be, for all intents and purposes, an
immovable object. The ample bosums could be moved along with the rest of
the upper body in order to reposition the centre of mass, but I wonder of
the bosums may follow slightly after the rest of the upper body, then
continue moving after the rest of the body has stopped, causing a degree
of unpredictability in the redistribution of mass.

Sorry Helen ;-)

S'arright... my ample bosums are very unpredictable ;-)

Cheers, helen s

in message <[email hidden]>, Danny

Colyer (') said:

wafflycat said:

Quoted message said:

I think I could use my large rear and ample bosums giving too high a
centre of gravity to be stable as an excuse :-)

and [email hidden] thunk:

Quoted message said:

shouldn't a higher CoG make it easier to balance?

Only if the weight is easy to move around in a controlled manner in
order to restore balance when one starts to fall. The large rear would
be plonked firmly on the seat and would be, for all intents and
purposes, an immovable object. The ample bosums could be moved along
with the rest of the upper body in order to reposition the centre of
mass, but I wonder of the bosums may follow slightly after the rest of
the upper body, then continue moving after the rest of the body has
stopped, causing a degree of unpredictability in the redistribution of
mass.

This hysteresis effect can be controlled by appropriate engineering of
the over-shoulder boulder holder.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; my other religion is Emacs

Mike Causer of said:

Here's a pic of Jon on Hooves (2?) with wicker basket, following the
Maker and Purveyor of Wicker Baskets to the Nobility, Gentry and
Other Cyclists, David Hembrow.

And not just bike baskets, I bought a linen basket and a waste basket from
him after finding out about him in this forum. Many thanks to whoever first
mentioned him, Jon probably.
--
Steph Peters
Chorlton Wanderers Cycling Group
Monthly slow and easy rides from South Manchester
http://www.sandbenders.demon.co.uk/cycling/chwan.htm

Jim Price said:

Stevie D said:

Quoted message said:

shouldn't a higher CoG make it easier to balance?

I always thought a _lower_ centre of gravity gave you better balance.

Imagine a straight line between your front and rear wheels as your
balance line. You want to keep your COG above this line.

If your COG is 25cm above ground, and you lean 5 degrees, your COG is
2.2cm outside your balance line - but if your COG is 1m above ground,
and you lean 5 degrees, your COG moves to 8.8cm outside your balance
line. This means that you are inherently less stable - factor in the
leverage effect that a higher COG has and you get a much greater pull
downwards.

Try balancing a pencil on it's end on your finger, then try something
similar but about a metre long. I've tried this theory out on two
significantly different heights of unicycle - the taller one was much
easier to balance on as it seemed like you had much more time between
when you noticed it starting to topple and it getting beyond what you
could recover from.

It didn't just seem like you had more time to control a wobble, you did.

There are two distinct factors at work in height of CofG in
balancing. The first is that the lower the CofG the more stable the
thing is, in that a certain lean angle generates a smaller force
increasing the lean, so static balance is more easily achieved. The
second is that the higher the CofG the longer it takes to fall
over. Since we have a finite reaction time, there is a minimum height
of CofG below which it takes concentration and risk of failure to keep
balanced. So the lower the CofG the better the staic balance, but the
higher the CofG the easier the dynamic balance. So the optimum height
is as low as possible which is above an uncomfortably demanding
reaction time height.

I'm sure it won't surprise anyone to learn that evolution in her
wisdom has equipped us with reaction times well able to stop us
falling over when standing up :-)

--
Chris Malcolm [email hidden] DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

wafflycat said:

"Ambrose Nankivell" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

wafflycat said:

Mr Clinch & Vernon are discussing steeds outside.

Roos & I are being sensible & having cake

And posting to usenet 😉

Will you be taking them for^W on a ride?

A

They've just departed en route to their evening destination in Norfolk.
It was lovely to meet them. We had ice cream, iced tea, cake... Pete
offered me a go on his streetmachine. I managed ooh, all of zero inches
on it - it felt very alien to me compared to the Trice. The extra wheel
on the Trice makes all the difference for me :-) Much chatting about
steeds and where to visit in Norfolk sur Velo.

Cheers, helen s

Was the cake iced?

Julesh