Which spokes support the load?

g-spot said:

Sandy said:

Quoted message said:

the spokes below the hub are not doing anything to support the hub.

Try taking them out.

As the load is applied progressively, the bottom-most spoke starts to carry
the load by reduced tension.

The greater the load, the lower the tension and the more supporting the
bottom spoke is doing,

When tension reduces to zero, the bottom spoke is providing its maximum
support and can be
removed.

Ummmmmm?

pk

pk said:

g-spot said:

Sandy said:

Quoted message said:

the spokes below the hub are not doing anything to support the hub.

Try taking them out.

As the load is applied progressively, the bottom-most spoke starts to carry
the load by reduced tension.

The greater the load, the lower the tension and the more supporting the
bottom spoke is doing,

When tension reduces to zero, the bottom spoke is providing its maximum
support and can be
removed.

Ummmmmm?

Ummmmmm, why do you seem so puzzled? What's up? What exactly is your problem?

In article <[email hidden]>, spam.trap100
@btinternet.com says...

Quoted message said:

g-spot said:

Sandy said:

Quoted message said:

the spokes below the hub are not doing anything to support the hub.

Try taking them out.

As the load is applied progressively, the bottom-most spoke starts to carry
the load by reduced tension.

The greater the load, the lower the tension and the more supporting the
bottom spoke is doing,

When tension reduces to zero, the bottom spoke is providing its maximum
support and can be
removed.

Ummmmmm?

Obviously a spoke carrying zero load is providing zero support.
Analyzing the forces acting on the hub by netting out opposing tensions
can occasionally be misleading.

Rick
The "wheel stands on its spokes" metaphor stands on its merits.

[email hidden] (David Wagner) wrote,

Quoted message said:

I would think that the weight load of the
bicycle is transferred from the frame to
the hubs, and then through the hub to
the *upper spokes* to the top of the rim
via tensile forces, and then from the top
of the rim to the bottom of the rim --- the
rim being held in shape by the spokes
through tension---and then to the tires
and the ground. Isn't this the correct
view?

You are correct. A spoked wheel is, as one engineer put it "A suspension
bridge with no end points. ALL the spokes support the hub in the center
of an evenly tensioned circular "Bridge". However, the spokes on the
upper half do bear slightly more of the load, gradually increasing the
closer to the zenith (top) you get.

Just look at how there are designed to attach to the wheel and hub.
Every spoke is designed to resist tension (pulling away), not
compression (pressing together), as would be encountered at the bottom
of the wheel.

- -

"May you have the wind at your back.
And a really low gear for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner
http://www.geocities.com/czcorner

g-spot said:

pk said:

g-spot said:

Sandy wrote:
>

> the spokes below the hub are not doing anything to support the hub.

Try taking them out.

As the load is applied progressively, the bottom-most spoke starts
to carry the load by reduced tension.

The greater the load, the lower the tension and the more supporting
the bottom spoke is doing,

When tension reduces to zero, the bottom spoke is providing its
maximum support and can be
removed.

Ummmmmm?

Ummmmmm, why do you seem so puzzled? What's up? What exactly is
your problem?

I don't have a problem. When asking what supports the hub, I look at the
hub, not at the bit of the rim in contact with the ground.

.........
Freebody diagram of the hub.

what forces are acting through which spokes?

Which spokes are acting to support the hub?

If you look at the rim you might get answers to the question " what forces
are acting to stop the rim/wheel deforming, but very little information
about the hub.

pk

On Fri, 19 Nov 2004 18:20:08 -0500, [email hidden]

(Chris Zacho 'The Wheelman') said:

[email hidden] (David Wagner) wrote,

Quoted message said:

I would think that the weight load of the
bicycle is transferred from the frame to
the hubs, and then through the hub to
the *upper spokes* to the top of the rim
via tensile forces, and then from the top
of the rim to the bottom of the rim --- the
rim being held in shape by the spokes
through tension---and then to the tires
and the ground. Isn't this the correct
view?

You are correct. A spoked wheel is, as one engineer put it "A suspension
bridge with no end points. ALL the spokes support the hub in the center
of an evenly tensioned circular "Bridge". However, the spokes on the
upper half do bear slightly more of the load, gradually increasing the
closer to the zenith (top) you get.

Just look at how there are designed to attach to the wheel and hub.
Every spoke is designed to resist tension (pulling away), not
compression (pressing together), as would be encountered at the bottom
of the wheel.

- -

"May you have the wind at your back.
And a really low gear for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner
http://www.geocities.com/czcorner

Dear Chris,

"However, the spokes on the upper half do bear slightly more
of the load, gradually increasing the closer to the zenith
(top) you get."

I'm trying to understand what you're saying in relation to
the "Post-Processing" table for the projected spoke tension
changes here:

http://www.achrn.demon.co.uk/astounding/ian/wheel/index.html

But I'm not even sure which column you would be looking at.

Are you talking about raw tension change (the "Tension"
column), the calculated vertical force of such changes with
the spoke angle considered (the "vertical force" column), or
something not shown here, or even something that contradicts
this kind of analysis?

That is, what tension changes or vertical lift (or what)
should I see in a 36-spoke wheel with a 1,000 newton load?

Carl Fogel

the load? once supported with the broken spokes!

pk said:

g-spot said:

pk said:

g-spot wrote:
> Sandy wrote:
>>
>
>> the spokes below the hub are not doing anything to support the hub.
>
> Try taking them out.

As the load is applied progressively, the bottom-most spoke starts
to carry the load by reduced tension.

The greater the load, the lower the tension and the more supporting
the bottom spoke is doing,

When tension reduces to zero, the bottom spoke is providing its
maximum support and can be
removed.

Ummmmmm?

Ummmmmm, why do you seem so puzzled? What's up? What exactly is
your problem?

I don't have a problem.

Then what are you on about?

Quoted message said:

When asking what supports the hub, I look at the
hub, not at the bit of the rim in contact with the ground.

Obviously.

Quoted message said:

........
Freebody diagram of the hub.

what forces are acting through which spokes?

Which spokes are acting to support the hub?

All of them.

Quoted message said:

If you look at the rim you might get answers to the question " what forces
are acting to stop the rim/wheel deforming, but very little information
about the hub.

Werehatrack said:

On Mon, 15 Nov 2004 16:09:48 -0600, David Wagner
<[email hidden]> wrote:

Quoted message said:

.. It is because this in
the case - that the greatest *change* in tension from the unladen
state is in those contact-point spokes - that these spokes are

incorrectly

Quoted message said:

said to be bearing the load.

Quoted message said:

This seems counterintuitive, but if you look at
the cyclic change in spoke loading during wheel rotation and the
instantaneous load on the remaining spokes, you will also see that it
is definitely not the case that the upper spokes are the ones with the
greatest tensile load at that point,
so it is demonstrably and
obviously incorrect to state that the hub hangs from the upper spokes
under load. Some transfer of the load occurs to many of the spokes,
in a variety of directions, but nowhere is the change as great as in
the contact-patch spoke(s), and in a properly tensioned wheel, nowhere
does the spoke tension increase due to loading approach the magnitude
of the unloaded tension.

Normal spoked wheel carrying load in the normal manner.

Draw a freebody diagram of the hub.

Which forces are acting in which direction?

Only the tension vectors associated with the tension in the upper spokes is
are acting to support the load.

it is demonstrably clear that the tension in the lower spokes is not
imposing a force on the hub to counteract the load,

The lower spoke are not bearing the load.

BUT, because

Quoted message said:

The wheel is a complex system. Its function is highly interdependent,
and not as simple as it might appear.

and if the load is increased the interdependency acts not to increase the
tension in the upper spokes but to decrease the tension in the lower spokes,
however, the physical state remains unchanged: the tension vectors
associated with the tension in the upper spokes are acting to support the
load.

pk

pk said:

Normal spoked wheel carrying load in the normal manner.
Draw a freebody diagram of the hub.
Which forces are acting in which direction?

You're attacking the straw man of a net upward force from the bottom
spokes again.
--
David Damerell <[email hidden]> Kill the tomato!

David Damerell said:

pk said:

Normal spoked wheel carrying load in the normal manner.
Draw a freebody diagram of the hub.
Which forces are acting in which direction?

You're attacking the straw man of a net upward force from the bottom
spokes again.

you clearly recognise the nonsense of the proposition, many do not. just
check the past threads.

For instance:

From Ian's fea page.

He bases his conclusions on the basic question:

#
"In asking whether the hub hangs or stands on the spokes, I really mean to
question where the structurally active spokes are. That is, if the spokes
which resist load are below the hub, I'd describe the hub as standing on the
lower spokes. If the spokes that resist load are above the hub, then I'd say
the hub was hanging. That is:

a.. Something hangs from a support if it is below the support.
b.. Something stands on a support if it is above the support"

#

Draw the free body diagram of the hub and it is clear that the hub is
supported by forces from above against gravity and other forces pulling it
down. Thus by the test he sets out, the hub hangs.

Actually it neither hangs nor stands, but forced to choose one or t'other,
hanging is less wrong than standing,

pk

pk said:

David Damerell said:

pk said:

Normal spoked wheel carrying load in the normal manner.
Draw a freebody diagram of the hub.
Which forces are acting in which direction?

You're attacking the straw man of a net upward force from the bottom
spokes again.

you clearly recognise the nonsense of the proposition, many do not.

That's not true. Your last set of quotes were selective, and neither
person said there was a net upwards force.

Quoted message said:

From Ian's fea page.

It does not say there is a net upwards force from the bottom spokes. You
are still attacking a straw man.
--
David Damerell <[email hidden]> Kill the tomato!

"David Damerell" <[email hidden]> a écrit dans le message
de :
news:[email hidden]...

Quoted message said:

pk said:

David Damerell said:

pk <[email hidden]> wrote:
>Normal spoked wheel carrying load in the normal manner.
>Draw a freebody diagram of the hub.
>Which forces are acting in which direction?
You're attacking the straw man of a net upward force from the bottom
spokes again.

you clearly recognise the nonsense of the proposition, many do not.

That's not true. Your last set of quotes were selective, and neither
person said there was a net upwards force.

Quoted message said:

From Ian's fea page.

It does not say there is a net upwards force from the bottom spokes. You
are still attacking a straw man.

The "straw man" keeps crowing that he is a "metaphor", which clearly is not
the case. It's just a miserable attempt to cover an inadequate vocabulary
(at best), or a pretentious defense of admiring the king's new clothes (more
likely). Keep on killing tomatoes - it seems that putting an end to this
sorry long exchange of tripe is not happening very soon.
--
Sandy
Verneuil-sur-Seine FR

*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

Quoted message said:

David Damerell <[email hidden]> Kill the tomato!

Sandy said:

"David Damerell" <[email hidden]> a écrit dans le message

Quoted message said:

pk <[email hidden]> wrote:

[PK claimed people said there was a net upwards force]

Quoted message said:

Quoted message said:

It does not say there is a net upwards force from the bottom spokes. You
are still attacking a straw man.

The "straw man" keeps crowing that he is a "metaphor", which clearly is not
the case.

What? The straw man exists only in PK's mind.

"Stands on the spokes" is a metaphor. That _is_ clearly the case. A lousy
confusing one, arguably, but a metaphor nonetheless.
--
David Damerell <[email hidden]> Kill the tomato!

"David Damerell" <[email hidden]> a écrit dans le message
de :
news:[email hidden]...

Quoted message said:

Sandy said:

The "straw man" keeps crowing that he is a "metaphor", which clearly is
not
the case.

Quoted message said:

What? The straw man exists only in PK's mind.

"Stands on the spokes" is a metaphor. That _is_ clearly the case. A lousy
confusing one, arguably, but a metaphor nonetheless.

From Merriam-Webster -

"metaphor - a figure of speech in which a word or phrase literally denoting
one kind of object or idea is used in place of another to suggest a likeness
or analogy between them."

Again, not quite a metaphor, but a poor use of language and an inadequate
capacity to express thoughts leads to the "standing on its spokes" rot. If
the word "stand" is meant to denote a particular other word, then it has
clearly failed. A metaphor is one which _successfully_ conveys the
reader/hearer to the alternative image. If not successful, it is neither a
mixed metaphor, or any such thing. Unless, now, you take the word
"metaphor" to have a meatphoric meaning other than its common one. Then it
becomes a meta-metaphor ??

All this, just to justify the incapacity of one purported author to stop
writing cutesy and get across the actual concept that could have been
conveyed.

At least it was 14C today, and we got in a nice 90 km in fog and drizzle.
Somewhat like getting through this thread and its parent.
--
Sandy
Verneuil-sur-Seine FR

*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

Quoted message said:

--
David Damerell <[email hidden]> Kill the tomato!

Sandy said:

"David Damerell" <[email hidden]> a écrit dans le message
de :

Quoted message said:

"Stands on the spokes" is a metaphor. That _is_ clearly the case. A lousy
confusing one, arguably, but a metaphor nonetheless.

From Merriam-Webster -
"metaphor - a figure of speech in which a word or phrase literally denoting
one kind of object or idea is used in place of another to suggest a likeness
or analogy between them."

Well, the word "stands" would literally denote that the bottom spokes are
in net compression but is used to suggest the idea that in the prestressed
structure they behave as if they are rigid members in compression.

That seems to fit the definition to me.

Quoted message said:

clearly failed. A metaphor is one which _successfully_ conveys the
reader/hearer to the alternative image.

The definition does not demand that; and indeed that is absurd, since
whether or not a particular figure of speech was a metaphor would depend
on the reader. Presumably it would vary from time to time as more or less
perceptive readers read it; and what it would be with one reader of each
sort looking at it is quite unclear.

Quoted message said:

All this, just to justify the incapacity of one purported author to stop
writing cutesy and get across the actual concept that could have been
conveyed.

This is also false. I've written nothing about Brandt here; I'm just
pointing out that it is useless for PK to so vigorously attack the idea
that the bottom spokes produce a net upwards force, because no-one
actually supposes that that is the case.

Quoted message said:

At least it was 14C today, and we got in a nice 90 km in fog and drizzle.
Somewhat like getting through this thread and its parent.

If you don't like it, don't read it. At least it's not about bloody
American politics.
--
David Damerell <[email hidden]> Kill the tomato!