When to Stop Pedalling?

[Claire Petersky]

Elisa Francesca Roselli <[email protected]> wrote in message
news:<[email protected]>...

> I'm agog when I see cyclists yakking away on their mobile phones or pedalling with no hands.

One of the great joys of my life is coasting down the big hill near my house on the way home at
night, with my arms outstretched, singing my little heart out.

Warm Regards,

Claire Petersky ([email protected])

Come to our recording concert Sunday June 22! http://www.tiferet.net/ Home of the meditative
cyclist: http://home.earthlink.net/~cpetersky/Welcome.htm Books just wanna be FREE! See what I mean
at: http://bookcrossing.com/friend/Cpetersky

 

[Andrew Bradley]

Ryan Cousineau:

> Tim McNamara <[email protected]> wrote:
>
> > In article <[email protected]>, Ryan Cousineau <[email protected]>
> > wrote:
> >
> > > The high-speed stability of a bicycle--assuming the bicycle's geometry is stable--is largely a
> > > matter of its momentum, not its traction. It resists changes in direction in proportion to its
> > > mass and speed.
> >
> > Pardon me, but isn't that the situation for all objects in motion?
> >
> > Tim "The faster you go, the rounder you get" McNamara
>
> Why, yes! It's one the simplest laws of the physics of objects with mass and velocity. But it
> points out that bicycles do not get their stability from the gyroscopic effects of their wheels.

No it doesn't.

Linear momentum does nothing to stop you toppling over since it produces no counter torque. Steering
out of a topple requires a certain amount of speed, that's all.

Andrew Bradley

 

[Jobst Brandt]

Tim Underwood writes:

>>> That is exactly what I'm talking about, and I've only seen one person outside the circus who
>>> could do it.

>> I had the pleasure of seeing Cino Cinelli, a man of 5'4" or so, in business suit, pant legs
>> inverted over knees, sit motionless on my 26" fame bicycle with his arms folded over his chest,
>> front wheel straight ahead. It can be done.

> I'm surprised he fitted! There's a similar height difference between myself (6'7") and my lady
> (5'6"), and she can't reach the bottom of the pedal arc while straddling the crossbar.

He didn't fit at all. He could only reach the pedals when the cranks were horizontal.

Jobst Brandt [email protected] Palo Alto CA

 

[Dennis P. Harri]

On Fri, 20 Jun 2003 11:31:47 +0200 in rec.bicycles.misc, Elisa Francesca Roselli
<[email protected]> wrote:

> And what exactly is a controvertial topic to cyclists?
>
h*lmets

critical mass

stop signs

 

[Jasper Janssen]

On 20 Jun 2003 13:30:31 -0700, [email protected] (Claire Petersky) wrote:

>One of the great joys of my life is coasting down the big hill near my house on the way home at
>night, with my arms outstretched, singing my little heart out.

"The hills are alive with the sound of my music"?

Jasper

 

[Jasper Janssen]

On 20 Jun 2003 13:38:03 -0700, [email protected] (Andrew Bradley) wrote:

>No it doesn't.
>
>Linear momentum does nothing to stop you toppling over since it produces no counter torque.
>Steering out of a topple requires a certain amount of speed, that's all.

No it doesn't.

It requires a certain amount of lateral movement of the contact patchesd to bring them back under
the center of gravity. This requires less extreme steering excursions at speed.

Jasper

 

[Prometheus]

<snip
> My favorite version is: An optimist thinks the glass is half full. A pessimist thinks the
> glass is half empty. And an engineer thinks the glass is twice as big as it needs to be.
>
> Pardon me for posting out of thread order. My ISP is in a bad mood, and I only see about half
> of what's posted. I've been using Google to keep up, and I'm hoping things will be fixed by
> tomorrow.

The one we like at school is : How many Carnegie Mellon students does it take to change a
light bulb?
4: 1 Civil and Environmental engineer to remove the light bulb and dispose of it in a way friendly
to the environmnet. 1 Mechanical engineer and 1 Electrical engineer to design a new light bulb
that never needs changing 1 Computer Science major to rewrite the code for the switch so it is
more efficient, more user-friendly, and uses less memory.

How many MIT students does it take?
5: 1 to call Carnegie Mellon and see how they handled the problem. 3 to take the credit for
CMU's design.

 

[Andrew Bradley]

Jasper Janssen:

>(Andrew Bradley) wrote:
>
> >No it doesn't.
> >
> >Linear momentum does nothing to stop you toppling over since it produces no counter torque.
> >Steering out of a topple requires a certain amount of speed, that's all.
>
> No it doesn't.
>
> It requires a certain amount of lateral movement of the contact patchesd to bring them back under
> the center of gravity.

No it doesn't.

Neither of the contact patches are under the CG. More hairs to split?

>This requires less extreme steering excursions at speed.

Speed makes balancing corrections easier. But it's not a momentum effect. What's your point?

Andrew Bradley

 

[Kevan Smith]

On Fri, 20 Jun 2003 23:41:39 -0800, [email protected] (Dennis P. Harris) from None wrote:

>h*lmets
>
>critical mass
>
>stop signs

Of course you realize, this means WAR!

Where's my Illudium Q-36 Explosive Space Modulator!

--
http://home.sport.rr.com/cuthulu/ human rights = peace

Minnesota but don't EMBARRASS me!!
3:46:41 PM 21 June 2003

 

[Jasper Janssen]

On 21 Jun 2003 12:41:46 -0700, [email protected] (Andrew Bradley) wrote:
>Jasper Janssen:
>>(Andrew Bradley) wrote:

>> >Linear momentum does nothing to stop you toppling over since it produces no counter torque.
>> >Steering out of a topple requires a
^^^^^^^^
>> >certain amount of speed, that's all.
>>
>> No it doesn't.
>>
>> It requires a certain amount of lateral movement of the contact patchesd to bring them back under
>> the center of gravity.
>
>No it doesn't.
>
>Neither of the contact patches are under the CG.

That's why I said "contact patches", as in the plural. The group of contact patches is under the
COG. If one contact patch, then that patch is directly under COG. If two, the the COG is on the line
between them. If three, the COG is on the triangle formed by them.

>>This requires less extreme steering excursions at speed.
>
>Speed makes balancing corrections easier. But it's not a momentum effect. What's your point?

Speed makes balancing corrections easier. It's not a requirement.

Jasper