for Clive efficient running of wire spoked wheels abandoned urcm
thirty-six
the removal of a thread with reference to an Ian Jackson posting.
On 9 Nov, 16:03, "Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote:
> "thirty-six" <thirty-...@live.co.uk> wrote in message
>
> news:0a9c8bb5-038e-4edc...@t2g2000yqn.googlegroups.com...
>
> Can you explain this a bit further?
>
> > Spokes acting purely in tension at all times versus bending as the
> > load is varied.
>
> vs
>
> > Rim assisting in suspension due to less spoke tension.
>
> Are you saying your spokes bend as the load is varied?
My spokes act purely in tension.
>
> Or are you saying the higher tension of a brandt-style wheel means the
> spokes don't act purely in tension at all times? Coz that seems really quite
> odd.
YES, that is the nub of it. He pays no attention to the interlace
crossing in its effects upon the rigidity of the wheel in either a
radial or lateral sense(wrt rim). Isn't it odd? He missed it.
Material changes of spokes mean it is important to address the
crossing point when not using soft spokes or the wheel will be overtly
stiff radially for acceptable lateral stability.
You can guess my opinion of Ian Jackson
thirty-six
Procida) wrote:
> thirty-six <thirty-...@live.co.uk> wrote:
> > Physical explanation for benefits.
> > Longer tyre patch (see next item)
>
> I don't get this.
>
> What kind of distortion of the rim would have to take place to make a
> significantly different tyre patch, and would the continuous distortion
> of the rim as it rotates not eventually damage it?
That was my suspicion and I still have some lightweight rims I have
not built up because I suspect they will be wasted for general use.
Their mileage may be limited by the continual distortion. From what I
have seen, the securing pins for the for the joining sleeve will work
loose. Modern rims seem to use a cement in addition to the sleeve
rather than pinning the sleeve. This looks to me like an attempt to
address the problem of wear affecting a sleeved joint. With a typical
medium or heavy rim it does not seem to affect it.
Ian Smith
>
> YES, that is the nub of it. He pays no attention to the interlace
> crossing in its effects upon the rigidity of the wheel in either a
> radial or lateral sense(wrt rim). Isn't it odd? He missed it.
In my copy, he discusses the effect of increasing the potential for
transfer of forces at crossings (on page 131, for example, there's a
description of a tied-and-soldered test).
You're a tied-and-soldered nut, aren't you?
If the spokes aren't tied and soldered, by what mechanism do you
propose force is transferred at the crossing?
regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|
NM
Real good fun watching you lycra loonies squabble, keep it up. I'm
sure there are many more laughs to be had yet.
thirty-six
>
> > YES, that is the nub of it. He pays no attention to the interlace
> > crossing in its effects upon the rigidity of the wheel in either a
> > radial or lateral sense(wrt rim). Isn't it odd? He missed it.
>
> In my copy, he discusses the effect of increasing the potential for
> transfer of forces at crossings (on page 131, for example, there's a
> description of a tied-and-soldered test).
>
> You're a tied-and-soldered nut, aren't you?
>
> If the spokes aren't tied and soldered, by what mechanism do you
> propose force is transferred at the crossing?
>
That's not my argument. It is a relatively minor point to what I'm
discussing.
Ian Smith
So, can I check I've understood: you brought up a claim, but it's not
relevant enough to discuss?
thirty-six
JB did not record any observations as to the lateral movement and
bending of the spokes as the wheel was loaded and unloaded. If he
had, he would of noted that as the wheel is loaded the bottom spokes
bow. It is this bowing which would cause the fatigue at the spoke
elbow. It is this bowing which compromises a wheels lateral
stability. It is this bowing which I do not allow in the wheels I
build.
There is more than one method to address the problem of bowing spokes
and tying and soldering in a profficient manner will help. The
modification of the interlace is the most effective way to improve a
wheel. As in least expenditure of time, effort and money. It may
take half an hour to modify your first wheel, but will take around 5
or so minutes after you have done a handful. When building the wheel
it takes an additional three minutes.
Ian Smith
JB does consider the effect (he discusses it wrt symmetrical or
mirrored so===poking), but apparently considers that it is not
significant.
I don't consider it significant. The bottom spokes remain in
tension, the bow is not significant, the stress range induced by the
lateral displacement effect is significantly lower than the stress
range variation that cause the lateral displacement. You're worrying
over a second-order effect which is completely swamped by the
principal effect. It's not significant.
You'll need to come up with something a bit more convincing than proof
by assertion. It will be easy for you to do - the spokes are nice
simple members, it's really just a geometry problem as to how much
lateral movement occurs given a particular change in tension of one of
the crossing spokes. Of you go - produce some numbers, demonstrate
(quantitatively) that it's a significant effect. I'll be astonished
if you can.
> There is more than one method to address the problem of bowing spokes
> and tying and soldering in a profficient manner will help.
I thought so. You're a tied-and-soldered nut.
thirty-six
Stick a straight edge against a spoke from the rim to the interlace
and undo the nipple by four turns and see what happens.
Ian Smith
> On 10 Nov, 21:50, Ian Smith <i...@astounding.org.uk> wrote:
> > On Tue, 10 Nov 2009, thirty-six <thirty-...@live.co.uk> wrote:
> > >
> > > �bending of the spokes as the wheel was loaded and unloaded. �If he
> > > �had, he would of noted that as the wheel is loaded the bottom spokes
> > > �bow. �It is this bowing which would cause the fatigue at the spoke
> > > �elbow. �It is this bowing which compromises a wheels lateral
> > > �stability. �It is this bowing which I do not allow in the wheels I
> > > �build.
> >
> > JB does consider the effect (he discusses it wrt symmetrical or
> > mirrored so===poking), but apparently considers that it is not
> > significant.
> >
> > I don't consider it significant. �The bottom spokes remain in
> > tension, the bow is not significant, the stress range induced by the
> > lateral displacement effect is significantly lower than the stress
> > range variation that cause the lateral displacement. �You're worrying
> > over a second-order effect which is completely swamped by the
> > principal effect. �It's not significant. �
> >
> > You'll need to come up with something a bit more convincing than proof
> > by assertion.
>
> Stick a straight edge against a spoke from the rim to the interlace
> and undo the nipple by four turns and see what happens.
That's your proof?
I agree, if the spoke tension changes, there's lateral movement.
As I said - it's a secondary effect. As you undo the nipple, there is
a very small change in stress distribution across the spoke section
attributable to lateral movements. There is a very large change in
spoke tension due to the fact that you've undone the nipple. You are
worrying about the very small effect. It is swamped by the very large
effect.
You are fussing about an irrelevance.
thirty-six
No, ability to obtain lateral stability in a wheel with a reasonable
spoke tension which permits rim deformation due to high loads and
improves the wheels efficiency and comfort.
The 'irrelevance' was allowing a rear wheel of mine to lose lateral
stability when cornering on a smooth road. It was a open4cd rim and
there was no way I could continue tensioning it without a considerable
increase in risking buckling. The wheel used typical components, it
was just that I'd put on some weight and got more effective at
cornering. The standard response would be more spokes, stiffer rim,
stiffer spokes, wider flanges. It is all unecessary. A better manner
in spoke installation gives the required lateral stability with normal
flange spacing.
thirty-six
> thirty-six <thirty-...@live.co.uk> considered Tue, 10 Nov 2009
> 14:36:17 -0800 (PST) the perfect time to write:
>
> >Stick a straight edge against a spoke from the rim to the interlace [of a factory wheel]
> >and undo the nipple by four turns and see what happens.
>
> You'll find that instead of going completely slack, the spoke will
> adopt a curved path.
Yes.
> Surely this is a benefit?
No. It is a definite disadvantage. It means the spoke does not adopt
the constant stress/strain relationship as expected of a metal in
tension. There is an additional bending component which modifies the
relationship. This means that the spokes fail to relieve the rim
where it is displaced by the riding load. It is also the cause of
lateral instability and faigue failure of the spokes. There is no
benefit to bowed spokes of steel wire.
> Spokes which can go completely slack are not good.
Religious belief!
> By kinking them into a series of straight lines you would be
> increasing the chance of that happening, for any given set of load,
> gauge and tension.
Ther's no chance of spokes becoming loose happening, it is positively
designed into the wheel for heavy loads, otherwise the rim buckles due
to the lateral instability, overtensioning of spokes and the failure
to relieve suficient spoke tension at the rims loading area.
Ian Smith
I have no idea what you think that says. I've tried several times,
but I cannot parse it into anything that makes sense.
> The 'irrelevance' was allowing a rear wheel of mine to lose lateral
> stability when cornering on a smooth road. It was a open4cd rim and
> there was no way I could continue tensioning it without a considerable
> increase in risking buckling.
I don't believe you. I think you didn't tension adequately, not
least because there is a relatively low lateral force on a wheel of a
cornering bicycle. If it's a trike, you might like to reduce the
dish.
Ian Smith
> On 12 Nov, 03:02, Phil W Lee <phil(at)lee-family(dot)me(dot)uk> wrote:
> > thirty-six <thirty-...@live.co.uk> considered Tue, 10 Nov 2009
> > 14:36:17 -0800 (PST) the perfect time to write:
>
> >
> > >Stick a straight edge against a spoke from the rim to the
> > >interlace [of a factory wheel] and undo the nipple by four turns
> > >and see what happens.
> >
> > You'll find that instead of going completely slack, the spoke will
> > adopt a curved path.
>
> Yes.
>
> > Surely this is a benefit?
>
> No. It is a definite disadvantage. It means the spoke does not
> adopt the constant stress/strain relationship as expected of a
> metal in tension. There is an additional bending component which
> modifies the relationship. This means that the spokes fail to
> relieve the rim where it is displaced by the riding load. It is
> also the cause of lateral instability and faigue failure of the
> spokes. There is no benefit to bowed spokes of steel wire.
Firstly, the spoke material does comply exactly with the expected
stress-strain relationship. The curved path does not cause a change
in the properties of the material. I have no idea what you mean here,
but if you really think the material fundamentally changes properties
depending what shape it adopts you're beyond reason.
Next, the curve does not cause lateral instability. What causes
lateral instability is riding on a wheel where you've loosened the
nipple four turns from where it ought to be. It's slack spokes that
cause lateral instability, not the curved profile that a slack spoke
adopts when the wheel is not under load.
Once more, you demonstrate an apparent inability to see the primary
cause of something, and latch onto triviality.
Further, bending stress does not cause more fatigue than tensile
stress. It's the micro-level principal tensile stress that matters,
not the macro-level stress distribution across the section. This is
why you get fatigue in a weld even in compression - it's micro-level
tension above yield stress at micro defects, the stresses
arising due to differential cooling. If you're looking at micro-level
stresses, the fact that the steel has a different stress way over on
the other side of the spoke (practically a millimetre away) is
completely irrelevant.
Further, the bowed shape arises because it is minimising the bending
stress - it's a minimum energy state for the boundary conditions. If
the spoken went straight and then turned a corner there would be
significantly higher bending stress than with the smooth curve.
> > Spokes which can go completely slack are not good.
> Religious belief!
You really are fixated on secondary matters.
A wheel with slack spokes does not buckle because the slack spokes
adopt a curved profile. A wheel with slack spokes buckles because the
slack spokes don't restrain the rim and don't conduct the load
directly to the hub, necessitating the applied load distribute further
round the rim.
Your arguments sounds very much like the chap proposing that it's the
trees rustling their leaves that makes the wind blow. He knows this
because when the rustle gently there's only a little breeze, but when
they wave their branches around there's a much stronger wind, and
if they positively thrash about there's a storm.
Rob Morley
Ian Smith <i...@astounding.org.uk> wrote:
> Your arguments sounds very much like the chap proposing that it's the
> trees rustling their leaves that makes the wind blow. He knows this
> because when the rustle gently there's only a little breeze, but when
> they wave their branches around there's a much stronger wind, and
> if they positively thrash about there's a storm.
>
I like that. It does seem rather appropriate too.
thirty-six
There was more than adequate tension on the spokes, the lower spoke(s)
did not become loose and the rim was unstable. It was not only
unstable on the road but unstable during trueing. I pedal through
the corners with my backside to the side of the saddle in the same way
a fixed wheel bike has to be ridden quickly through the corners. It
was (and is) a bicycle. The spokes are 1.6mm stainless DTswiss both
sides (32 0f them), my weight 13st+ . This was a common complaint
with this rim. After modification of the spokes, not only did my road
cornering become secure, but I also had sufficient lateral stability
to use the wheel aggresively off road, until I started to think about
axle breakage. I dont use those wheels much because they are stiff in
comparison to my others and I dont have tyres I can use with abandon,
they all having little sidewall protection.
thirty-six
> On Thu, 12 Nov 2009, thirty-six <thirty-...@live.co.uk> wrote:
> > On 12 Nov, 03:02, Phil W Lee <phil(at)lee-family(dot)me(dot)uk> wrote:
> > > thirty-six <thirty-...@live.co.uk> considered Tue, 10 Nov 2009
> > > 14:36:17 -0800 (PST) the perfect time to write:
>
> > > >Stick a straight edge against a spoke from the rim to the
> > > >interlace [of a factory wheel] and undo the nipple by four turns
> > > >and see what happens.
>
> > > You'll find that instead of going completely slack, the spoke will
> > > adopt a curved path.
>
> > Yes.
>
> > > Surely this is a benefit?
>
> > No. It is a definite disadvantage. It means the spoke does not
> > adopt the constant stress/strain relationship as expected of a
> > metal in tension. There is an additional bending component which
> > modifies the relationship. This means that the spokes fail to
> > relieve the rim where it is displaced by the riding load. It is
> > also the cause of lateral instability and faigue failure of the
> > spokes. There is no benefit to bowed spokes of steel wire.
>
> Firstly, the spoke material does comply exactly with the expected
> stress-strain relationship. The curved path does not cause a change
> in the properties of the material. I have no idea what you mean here,
> but if you really think the material fundamentally changes properties
> depending what shape it adopts you're beyond reason.
I said the spoke, not the wire, not the metal, not the material, the
element, the spoke.
>
> Next, the curve does not cause lateral instability. What causes
> lateral instability is riding on a wheel where you've loosened the
> nipple four turns from where it ought to be. It's slack spokes that
> cause lateral instability, not the curved profile that a slack spoke
> adopts when the wheel is not under load.
I've made the changes and made the observations. Get rid of the bows
and you get rid of the instability.
>
> Once more, you demonstrate an apparent inability to see the primary
> cause of something, and latch onto triviality.
You're ignorant. Are you choosing this or does it come naturally?
>
> Further, bending stress does not cause more fatigue than tensile
> stress.
Of course it does. That small angular displacement at the end of the
spoke is magnified many times due to leverage, the thinner the spoke
the greater the leverage. Note the popularity of 14/15swg spokes. No
reason for these whatsoever except to reduce the leverage caused by
the bending on a thin spoke. Except if you get rid of the bending
then you can use the straight 15swg spokes with easier installation
and less cost.
> It's the micro-level principal tensile stress that matters,
> not the macro-level stress distribution across the section.
Bending increases the tensile stress on the outside of the bend.
>This is
> why you get fatigue in a weld even in compression - it's micro-level
> tension above yield stress at micro defects, the stresses
> arising due to differential cooling.
Dont try Brandt tricks, it wont wash with me. that is a total
irellevance and I'm not even going to consider whether or not you have
actually potred a fact or a route for diversion.
> If you're looking at micro-level
> stresses, the fact that the steel has a different stress way over on
> the other side of the spoke (practically a millimetre away) is
> completely irrelevant.
It's totally relevant that this is recognised. Upon examination of a
fractured spoke the tide marks point to the direction of bending and
the side of greatest stress. The other side will be necked down
slightly the amount dependent upon the hardness of the spoke.
>
> Further, the bowed shape arises because it is minimising the bending
> stress - it's a minimum energy state for the boundary conditions. If
> the spoken went straight and then turned a corner there would be
> significantly higher bending stress than with the smooth curve.
The cyclic nature of the bending hardens the highest stressed zone
(where the spoke leaves the flange) and it is this which cracks,
causing stress concentrations which further advance the crack.
>
> > > Spokes which can go completely slack are not good.
> > Religious belief!
>
> You really are fixated on secondary matters.
>
> A wheel with slack spokes does not buckle because the slack spokes
> adopt a curved profile. A wheel with slack spokes buckles because the
> slack spokes don't restrain the rim and don't conduct the load
> directly to the hub, necessitating the applied load distribute further
> round the rim.
Buckling is due to compressive overload along long sections. There is
no way that you can buckle a typical rim unless the rim is overloaded
by excessive spoke tension. Injuries made to a rim by kerbing a
loosely spoked wheel will be dents. Tightening spokes cannot avoid
this, but can make what would just be a minor dent turn into a major
buckle, possibly involving the whole rim.
>
> Your arguments sounds very much like the chap proposing that it's the
> trees rustling their leaves that makes the wind blow. He knows this
> because when the rustle gently there's only a little breeze, but when
> they wave their branches around there's a much stronger wind, and
> if they positively thrash about there's a storm.
>
It's you that has it arse about. the rim is stable without spoke
tension, add spoke tension and its still stable, add more tension it
becomes unstable, this is buckling. If you straighten the spokes
before tensioning, you do not have to tension the spokes so tight to
make them straight, theyre already there without tension. The spoke
tension may then be adjusted to give the required rim response for the
conditions it must endure. You do not have o try to balance tension
in an effort to find stability, with straightened spokes, it all falls
into place.
Ben C
[...]
> Further, bending stress does not cause more fatigue than tensile
> stress. It's the micro-level principal tensile stress that matters,
> not the macro-level stress distribution across the section. This is
> why you get fatigue in a weld even in compression - it's micro-level
> tension above yield stress at micro defects, the stresses
> arising due to differential cooling. If you're looking at micro-level
> stresses, the fact that the steel has a different stress way over on
> the other side of the spoke (practically a millimetre away) is
> completely irrelevant.
Not sure exactly what thirty-six's original point was, but bending
stress on spokes whose elbows are not as close as possible to the flange
causes high tensile stress (on the outside of the bend).
I'm not saying anything here that isn't obvious-- anyone can bend a bit
of coat hanger wire, but elongating one by pulling on the ends is much
harder. The difference is just leverage.
In a wheel the 1000N tension or so in each spoke is low enough to keep
the wire safely away from yield stress if it's pulled along its axis.
But if the elbow's sticking out from the hub, or if the wire is pulled
at a different angle, you've got a moment, and there are much higher
stresses at the bend, enough to cause fatigue.
Ian Smith
> On 12 Nov, 22:19, Ian Smith <i...@astounding.org.uk> wrote:
> > On Thu, 12 Nov 2009, thirty-six <thirty-...@live.co.uk> wrote:
> > > �On 12 Nov, 03:02, Phil W Lee <phil(at)lee-family(dot)me(dot)uk> wrote:
> > > > thirty-six <thirty-...@live.co.uk> considered Tue, 10 Nov 2009
> > > > 14:36:17 -0800 (PST) the perfect time to write:
> > >
> > > �adopt the constant stress/strain relationship as expected of a
> > > �metal in tension. �There is an additional bending component which
> > > �modifies the relationship. �This means that the spokes fail to
> > > �relieve the rim where it is displaced by the riding load. �It is
> > > �also the cause of lateral instability and faigue failure of the
> > > �spokes. �There is no benefit to bowed spokes of steel wire.
> >
> > Firstly, the spoke material does comply exactly with the expected
> > stress-strain relationship. �The curved path does not cause a change
> > in the properties of the material. �I have no idea what you mean here,
> > but if you really think the material fundamentally changes properties
> > depending what shape it adopts you're beyond reason.
>
> I said the spoke, not the wire, not the metal, not the material, the
> element, the spoke.
So teh spoke adopts a different behaviour, but teh material from
which it is made does not?
> > Next, the curve does not cause lateral instability. �What causes
> > lateral instability is riding on a wheel where you've loosened the
> > nipple four turns from where it ought to be. �It's slack spokes
> > that cause lateral instability, not the curved profile that a
> > slack spoke adopts when the wheel is not under load.
>
> I've made the changes and made the observations. Get rid of the bows
> and you get rid of the instability.
I still don't believe you.
> > Further, bending stress does not cause more fatigue than tensile
> > stress.
>
> Of course it does.
You state as "of course" a premise that contradicts every previously
stated characteristic of fatigue. Bending stress does not inherently
cause more fatigue than tensile stress. At the level that is
relevant, it's just stress.
> > �It's the micro-level principal tensile stress that matters,
> > not the macro-level stress distribution across the section. �
>
> Bending increases the tensile stress on the outside of the bend.
Yes, and it's irrelevant whether it is derived from bending or from
tension, and the bending component is small anyway.
> > This is why you get fatigue in a weld even in compression - it's
> > micro-level tension above yield stress at micro defects, the
> > stresses arising due to differential cooling.
>
> Dont try Brandt tricks, it wont wash with me. that is a total
> irellevance and I'm not even going to consider whether or not you have
> actually potred a fact or a route for diversion.
Eh? In what way is it 'tricks' to illustrate why what you've said is
wrong.
I give up.
I'm sure you're right and every metallurgist and analyst and
structural engineer and wheel-builder that ever lived has it all
wrong.
thirty-six
I agree, and that is what I've said. Even at (a high) 1000N of
tension, the spoke is still likely to be four times under the yield
stress and only bending loads will put the spoke into yield. The rim
will distort to uselessness long before stress levels induced purely
by spoke extension could possibly take a spoke into yield.
thirty-six
contradictions again:
> > I said the spoke, not the wire, not the metal, not the material, the
> > element, the spoke.
>
> So teh spoke adopts a different behaviour, but teh material from
> which it is made does not?
With poor installation the spoke bends, this bending must be included
in an analysis of wheel structure and spoke failure for it to be
valid. Treating the spoke as a purely tensile material is wrong when
it clearly isn't.
>
> > > Next, the curve does not cause lateral instability. What causes
> > > lateral instability is riding on a wheel where you've loosened the
> > > nipple four turns from where it ought to be. It's slack spokes
> > > that cause lateral instability, not the curved profile that a
> > > slack spoke adopts when the wheel is not under load.
>
> > I've made the changes and made the observations. Get rid of the bows
> > and you get rid of the instability.
>
> I still don't believe you.
>
> > > Further, bending stress does not cause more fatigue than tensile
> > > stress.
>
> > Of course it does.
It is greater. The precise magnification of stress at the outside of
the bend is relevant to the the treatment of the wire in its
manufacture and the forming of the elbow. Subsequent heat treatment
and tempering of the spokes may permit a spoke to bend during service
without inducing edge stress levels high enough to cause surface
cracking. An unecessary expense because simply shaping the spokes
during their fitting removes the bending loads to the spoke. With the
correct tooling, a man can perform the spoke modifiction in a wheel in
a sequential manner, spending no more than two seconds for each pair
of spokes. The spokes may be preformed before insertion through the
hubs and so no additional build time is required.
>
> You state as "of course" a premise that contradicts every previously
> stated characteristic of fatigue. Bending stress does not inherently
> cause more fatigue than tensile stress. At the level that is
> relevant, it's just stress.
In bending, it is magnified.
>
> > > It's the micro-level principal tensile stress that matters,
> > > not the macro-level stress distribution across the section.
>
> > Bending increases the tensile stress on the outside of the bend.
>
> Yes, and it's irrelevant whether it is derived from bending or from
> tension, and the bending component is small anyway.
In bending, it is magnified.
> Eh? In what way is it 'tricks' to illustrate why what you've said is
> wrong.
>
> I give up.
What a surprise.
>
> I'm sure you're right and every metallurgist and analyst and
> structural engineer and wheel-builder that ever lived has it all
> wrong.
Have you seen the Dunlop and Rudge wheel documentation? Perhaps you
could point me to the development and build techniques they used for
their record breaking wheels. Both these companies were involved
extensively in aeronautic work during the war effort of the Great War
and gave thorough investigation of the materials used annd their
form. Both these companies were large producers of suspension wheels
and yet I fail to see any reference to the work they have done by
those who today profess to understand the structure of a tension
wheel. Nor have I seen references to Cayley, Bauer or Palmer. There
a quite a few others having influence in the structure but the
greatest knowledge is likely to be held in Dunlop and Rudge archives.
Ian Smith
>
> With poor installation the spoke bends, this bending must be
> included in an analysis of wheel structure and spoke failure for it
> to be valid.
If and only if you are intent on analysing a poorly-built wheel that
fails as soon as it is ridden. I'm certainly not, and I very much
doubt that JB was either. If you want to analyse a badly built wheel
that fails as soon as you ride it, go ahead.
Even if it were true that when analysing your useless wheel you should
use a method that does not assume purely tensile spoke elements, that
says nothing about the appropriate analysis of a properly tensioned
wheel.
You have fixated on assuming that a wheel with loose spokes fails
because the spokes bow. As I said, this is just like the argument
that the trees waving their leaves make the wind blow.
Yes, loose spokes bow.
Yes, wheels with loose spokes fail.
No, the failure is not caused by the spokes bowing.
thirty-six
> On Fri, 13 Nov, thirty-six <thirty-...@live.co.uk> wrote:
>
> > With poor installation the spoke bends, this bending must be
> > included in an analysis of wheel structure and spoke failure for it
> > to be valid.
>
> If and only if you are intent on analysing a poorly-built wheel that
> fails as soon as it is ridden. I'm certainly not, and I very much
> doubt that JB was either. If you want to analyse a badly built wheel
> that fails as soon as you ride it, go ahead.
Yes, I purposely observed and analysed an obviously imperfect wheel.
I also observed and analysed wheels which had been junked because they
were 'shot'. They rode a little unevenly but still supported heavy
loads despite loose spokes. None fell apart or failed in any way.
>
> Even if it were true that when analysing your useless wheel you should
> use a method that does not assume purely tensile spoke elements, that
> says nothing about the appropriate analysis of a properly tensioned
> wheel.
>
> You have fixated on assuming that a wheel with loose spokes fails
> because the spokes bow. As I said, this is just like the argument
> that the trees waving their leaves make the wind blow.
You must be confusing be with =someone else. Bowed spokes affect all
wheels, whether tightly spoked or not. Loose spokes do not make a
wheel fail. There is an optimum spoke tension and bows must not be
present.
>
> Yes, loose spokes bow.
and do tight spokes.
>
> Yes, wheels with loose spokes fail.
less common than wheels with over tight spokes.
>
> No, the failure is not caused by the spokes bowing.
Buckled wheels are caused by insufficient lateral stability. Bowed
spokes leave a wheel laterally unstable. Bowed spokes are the
predominant cause of a buckled wheel.
From Dan Rudge and Co. 1887
"The SPOKES are tangential, and present the following advantages over
other of a similar pattern:-
"First, the tendency of the tangential to snap at the rim is
obviated by securing them with a concealed lock-nut and washer, making
them practically but-ended, and doubly strong at this point.
Rudge Spokes
"Second, instead of lacing back and forth from the rim to the
hub in nearly parallel directions, they now end at the hub and are
firmly riveted on the Inside after passing through it. The spoke is
thus single, and by being made heavier at the halt, the tendency of
snapping is entirely done away with. The system of crossing is also a
new one, and works to perfection, being accomplished by one spoke
passing over and under another in such a way that each spoke holds its
neighbor firmly in place, consequently, a rattle is impossible. Again,
the spokes are placed at right angles to each other, which not only
makes the wheel very much stronger and more rigid, but keeps it true
and prevents any possibility of buckling by ordinary use.
"The best recommendation for this particular spoke is the
universal satisfaction it has given in the last three years.
"Many manufacturers have tried to copy it, with a greater or
less number of crosses, and the result has been that the wheel has
been either too loose or far too rigid. If the spokes in a tangent
wheel are not laced tightly, it will be found that when the rider is
on the machine the upper spokes will be very tight, while those
directly beneath him, on the under side of the wheel, will be found
very loose, making it almost impossible for the wheel to be rigid and
to stand the required strain. On the other hand, if the wheel is a
complete network of spokes, crossing and recrossing, and all firmly
brazed to each other, the wheel is practically solid, and although
rigidity is to be desired, there must be sufficient give in the
machine to be able to stand the wear and tear.*
"With the Rudge spoke it will be seen at a glance that it is
unequalled for simplicity of construction, rigidity, and ease of
replacing in case of breakage."
* "sufficent give in the machine to be able to stand wear and
tear." a lacking in other manufacturers machines. Rudge went on to
be the largest manufacturer of wire spoke wheels as Rudge-Whitworth
because they were succesful because they employed the best methods.
SUFFICIENT GIVE
Ben C
Indeed, and I am convinced that bending at the elbow is the first place
to look if you're getting fatigue failures there.
Not sure whether kinking them at the crossing would help much with that
though, but maybe it does.
I once saw a 3x wheel where the spokes had also been interleaved at the
second crossing, very close to the hub. Looked a bit strange.
thirty-six
> >and do tight spokes.
>
> Very little if they're tight enough.
'Tight enough' for what, rim destruction?
> >Buckled wheels are caused by insufficient lateral stability.
>
> Ok so far.
>
> > Bowed
> >spokes leave a wheel laterally unstable.
>
> Slack spokes leave a wheel laterally unstable.
No, you can have a sixth of the wheel running with slack spokes and
still have lateral stability.
>
> > Bowed spokes are the
> >predominant cause of a buckled wheel.
>
> No, bowed spokes are a sign that the spokes are not tight enough.
Tight enough for WHAT? What tightness do you think a spoke needs?
Why?
> If you bend them so that they are straight even when loose, they still
> perform as slack spokes rather than tight ones - contributing nothing
> to lateral stability.
They are braced by the spacing of the hub flanges, this provides the
stability required. Just like holding a broom which is resting on the
floor, steady by gripping with your hand. You cannot apply tension
with your arm yet you stabilize the broom should it be subjected to an
external force, such as by Mrs Jones from next door "that's my broom,
give it back here!" Yet when the external force attempts to remove
the broom, then your arm goes in to tension, resisting the external
force. You do not need to stress it befoere it is needed or you will
tire it out. the same extra stress on a spoke will also tire it out
before its time.
> None of that says anything about bending the spokes at their crossing
> points though.
No because its about a high wheel. I was just showing that they had
considered that radially overly stiff wheels were a problem quite
early.
>
> It correctly points out that when the lower spokes slacken under load,
> stability is compromised.
Only when the spokes become very loose. As in rattling in the holes
with only the weight of the rider and no dynamic additional force due
to stones or cornering. I have ridden wheels in this state and the
bicycle drifts down the camber of the road. Just taking out the slack
from the nipples by going around the wheel and adding a 1/4 turn makes
the wheel stable. For cobbled roads, a little more is needed or the
wheel is liable to track the valley between the cobbles. This is not
a great concern unless travelling quickly when the affect on the
steering may be too great.
thirty-six
> So you believe that it's not necessary for the lower 60° if the rim to
> be stable.
It's stabilized by the fore and aft spokes and the upper spokes. It's
an arch. Its a span that the rim can manage.
> >Tight enough for WHAT? What tightness do you think a spoke needs?
> >Why?
>
> Tight enough that it never goes slack (i.e. tension reduces to zero)
> in any regular use, including reasonably foreseeable shock loading due
> to hitting bumps.
There is no reason for the lowest spokes to stay tight, they do not
and can not contribute to the support of the wheel for their force is
in the same direction as the load upon the wheel and therefore
contributing to its load rather than working in opposition to the
load.
>
Onthe Dan Rudge extract:
> Where do they state that any looseness, at any stage, is acceptable?
How else are you going to get "sufficient give?"
>
> > I have ridden wheels in this state and the
> >bicycle drifts down the camber of the road. Just taking out the slack
> >from the nipples by going around the wheel and adding a 1/4 turn makes
> >the wheel stable. For cobbled roads, a little more is needed or the
> >wheel is liable to track the valley between the cobbles. This is not
> >a great concern unless travelling quickly when the affect on the
> >steering may be too great.
>
> So the wheel with looser spokes is less stable.
When taken to the extreme a loosley spoked wheel will become unstable
with increasing load.
> Tightly spoked wheels are more stable, right up to the point where the
> tension exceeds the strength of the components.
Not true. The rim will buckle. The tighter spoked wheel will also
give a harsh ride.
> Bending the spokes around each other at their crossing only stress
> relieves that bend in the spoke which will be produced by tension
> anyway. Since this is not where spokes typically fail, it seems to be
> an irrelevance.
Putting bends at the interleave prevents bending action of the spoke
at the hub flange, the place where spokes typically fail. Putting
these bends in also stiffens the spoking so that the fore, aft and
upper spokings support the rim more effectively and the lower spokes
will detension easily so not contributing as much to the loading of
the rim where it is already displaced by the road. With high loads
the lowest spokes are completey relieved as the force from the road is
taken by the rim.
Ian Smith
>
> There is no reason for the lowest spokes to stay tight, they do not
> and can not contribute to the support of the wheel for their force is
> in the same direction as the load upon the wheel and therefore
> contributing to its load rather than working in opposition to the
> load.
At which point I hope it is obvious to all that 36 is either trolling,
or (more likely, I think) actually does not understand that which he
professes to be expert in. In either case, the futility of extending
the conversation further is obvious, I think.
Marc
> On Sat, 14 Nov 2009 (PST), thirty-six <thirt...@live.co.uk> wrote:
>> There is no reason for the lowest spokes to stay tight, they do not
>> and can not contribute to the support of the wheel for their force is
>> in the same direction as the load upon the wheel and therefore
>> contributing to its load rather than working in opposition to the
>> load.
>
> At which point I hope it is obvious to all that 36 is either trolling,
> or (more likely, I think) actually does not understand that which he
> professes to be expert in.
You mean that he's talking bullshit! Surely not?
In either case, the futility of extending
> the conversation further is obvious, I think.
>
It's entertaining him watching him make a tit of himself!
thirty-six
> On Sat, 14 Nov 2009 (PST), thirty-six <thirty-...@live.co.uk> wrote:
>
> > There is no reason for the lowest spokes to stay tight, they do not
> > and can not contribute to the support of the wheel for their force is
> > in the same direction as the load upon the wheel and therefore
> > contributing to its load rather than working in opposition to the
> > load.
>
> At which point I hope it is obvious to all that 36 is either trolling,
> or (more likely, I think) actually does not understand that which he
> professes to be expert in. In either case, the futility of extending
> the conversation further is obvious, I think.
>
Would you like to show how a spoke in tension within 15 deg of
vertical is assisting in holding up the axle from the ground?
The force is in exactly the same direction as the riding load, that of
bringing together the hub and the ground. Having less of that is a
good thing, so the bottom spokes should be releived as much as
possible by correct construction method. This means that the spokes
must become loose at some point to give the greatest load capacity
without wheel buckling.
thirty-six
> thirty-six <thirty-...@live.co.uk> considered Sat, 14 Nov 2009
> >It's stabilized by the fore and aft spokes and the upper spokes. It's
> >an arch. Its a span that the rim can manage. [60deg of span of rim]
>
> Unless it gets some lateral force applied.
> It was lateral stability we were discussing, and an arch
> (geometrically speaking) has none at all.
This is only a problem with bowed spokes. With the bows removed in a
interlaced wheel the fore/upper/aft spokes provide the lateral
stability that the inverted supporting arch needs. The new elbows
form a steady and more rigid structure and the spokes have a lower
tendency to slide across each other.
>
> >There is no reason for the lowest spokes to stay tight, they do not
> >and can not contribute to the support of the wheel for their force is
> >in the same direction as the load upon the wheel and therefore
> >contributing to its load rather than working in opposition to the
> >load.
>
> Unless you are reaching tensions which will exceed the yield point of
> components, that is not a problem.
Yes, the rim will tear and buckle. There is no reason at all to
overstress the rim by excess spoke tension. Form elbows at the
interlace and the rim becomes more laterally stable at lower spoke
tensions. Win, win.
>
>
>
> >Onthe Dan Rudge extract:
>
> >> Where do they state that any looseness, at any stage, is acceptable?
> >How else are you going to get "sufficient give?"
>
> Elasticity.
Yes, of the rim and spokes. But the tension of the spokes must not be
so high that the rim cannot work, because if the rim cannot work then
neither can the spokes.
>
>
>
> >> > I have ridden wheels in this state and the
> >> >bicycle drifts down the camber of the road. Just taking out the slack
> >> >from the nipples by going around the wheel and adding a 1/4 turn makes
> >> >the wheel stable. For cobbled roads, a little more is needed or the
> >> >wheel is liable to track the valley between the cobbles. This is not
> >> >a great concern unless travelling quickly when the affect on the
> >> >steering may be too great.
>
> >> So the wheel with looser spokes is less stable.
> >When taken to the extreme a loosley spoked wheel will become unstable
> >with increasing load.
>
> No need for extremes - zero tension = zero lateral stability.
I have run wheels which continually showed no tension in the spokes as
they passed the bottom of the wheel, it is no problem on a smooth
road. Its only when a few of the spokes are coming loose and the road
is not dead smooth or has significant camber does a larger span of
completely detensioned spokes become a problem. Remember, I bend the
spokes at the interlace making a more stable wheel.
>
>
>
> >> Tightly spoked wheels are more stable, right up to the point where the
> >> tension exceeds the strength of the components.
>
> >Not true. The rim will buckle. The tighter spoked wheel will also
> >give a harsh ride.
>
> Only if you have exceeded the strength of the components (in your
> example, the rim).
Buckling point is not the strength of the rim, the buckling point is
affected by the compressive load in the rim and the stability provided
by the spokes. So reducing the rims load by reducing spoke tension is
a good thing and elbowing the spokes at the interlace to imrove
stability is a good thing to do.
> Read it again, and try to understand what is included in "components".
Huh?
>
> >> Bending the spokes around each other at their crossing only stress
> >> relieves that bend in the spoke which will be produced by tension
> >> anyway. Since this is not where spokes typically fail, it seems to be
> >> an irrelevance.
>
> >Putting bends at the interleave prevents bending action of the spoke
> >at the hub flange, the place where spokes typically fail. Putting
> >these bends in also stiffens the spoking so that the fore, aft and
> >upper spokings support the rim more effectively and the lower spokes
> >will detension easily so not contributing as much to the loading of
> >the rim where it is already displaced by the road. With high loads
> >the lowest spokes are completey relieved as the force from the road is
> >taken by the rim.
>
> That is so confused that I can't even work out where to start.
> You seriously seem to be proposing that leaving the most stressed
> portion of the rim totally unsupported is a good thing.
It's only the most stressed if you have spoke tension assisting in its
demise. If the spoke tension at the bottom is relieved then the
circumferential compressive load on the rimi n that area is also
relieved, in its place is a bending load (due to road force) which can
now be easily coped with. The bending stress from the road still has
to be carried by the wheel in addition to excess spoke tension in your
overtensioned wheel.
So the rim at the base is not stressed any more in my wheels, the
stresses change from a compressive inline load to a bending load.as
evidenced by the rim displacement observed through occasional spoke
chatter over rough ground. BTW, I think this can be eliminated with
fibre washers under the nipples.
>
> I can only conclude that you like tacos.
With a tomato dip.
Marc
.
>>>> So the wheel with looser spokes is less stable.
>>> When taken to the extreme a loosley spoked wheel will become unstable
>>> with increasing load.
>> No need for extremes - zero tension = zero lateral stability.
>
> I have run wheels which continually showed no tension in the spokes as
> they passed the bottom of the wheel, it is no problem on a smooth
> road. Its only when a few of the spokes are coming loose and the road
> is not dead smooth or has significant camber does a larger span of
> completely detensioned spokes become a problem. Remember, I bend the
> spokes at the interlace making a more stable wheel.
Show it's more stable or be labeled a bullshitter!
Don't forget , you didn't like URCM because you weren't allowed to
discuss your ideas, now's your chance...
thirty-six
A wheel with unmodified spokes will wobble with tension still existant
in the lower spokes. That, due to a doubling of load, and the rear of
the bike tracking wide in a corner, without extra load, is what
prompted me to investigate "WHY?" and "can I improve this apology of a
wheel?" I could and I did. That same wheel which was causing
problems carried the same doubled up load over the same cobbled road
at a greater speed without wobbling. That IS MORE STABLE. The same
goes for cornering with my backside off the the inside of the saddle.
Same gear, higher speed, same corner, no discerible tracking error at
the rear. It is also clear when building up the wheels that they are
more stable, no chasing wobbles around the rim, it all comes together
cleanly with rims that otherwise would be difficult, such as any under
20mm wide.
Marc
> On 14 Nov, 23:55, Marc <initial.surn...@btintrenet.co.uk> wrote:
>> thirty-six wrote:
>>
>> .
>>
>>>>>> So the wheel with looser spokes is less stable.
>>>>> When taken to the extreme a loosley spoked wheel will become unstable
>>>>> with increasing load.
>>>> No need for extremes - zero tension = zero lateral stability.
>>> I have run wheels which continually showed no tension in the spokes as
>>> they passed the bottom of the wheel, it is no problem on a smooth
>>> road. Its only when a few of the spokes are coming loose and the road
>>> is not dead smooth or has significant camber does a larger span of
>>> completely detensioned spokes become a problem. Remember, I bend the
>>> spokes at the interlace making a more stable wheel.
>> Show it's more stable or be labeled a bullshitter!
>>
>> Don't forget , you didn't like URCM because you weren't allowed to
>> discuss your ideas, now's your chance...
>
> A wheel with unmodified spokes will wobble with tension still existant
> in the lower spokes.
How much?
That, due to a doubling of load, and the rear of
> the bike tracking wide in a corner, without extra load, is what
> prompted me to investigate "WHY?" and "can I improve this apology of a
> wheel?"
Double of what? Oh never mind suddenly there was no extra load! Make up
your mind, let's have one bit of bullshit at a time!
I could and I did.
And the proof is where?
That same wheel which was causing
> problems carried the same doubled up load over the same cobbled road
> at a greater speed without wobbling.
How much greater ?
That IS MORE STABLE. The same
> goes for cornering with my backside off the the inside of the saddle.
> Same gear, higher speed, same corner, no discerible tracking error at
> the rear. It is also clear when building up the wheels that they are
> more stable, no chasing wobbles around the rim, it all comes together
> cleanly with rims that otherwise would be difficult, such as any under
> 20mm wide.
Do you have some sort of cognitive problem, in that you can't
differentiate between talking about and proving?
thirty-six
bye
Marc
Keitht
>
> I'm sure you're right and every metallurgist and analyst and
> structural engineer and wheel-builder that ever lived has it all
> wrong.
And he still wonders why he gets his posts blocked over on urcm.
When he posts the equivalent of 'I've got my hands over my ears and
I'm humming very loudly' time after time on urcm it's no real surprise.
He is, apparently, the Doug of wheelbuilding.
--
Its never too late to reinvent the bicycle
Naqerj
> On Sat, 14 Nov 2009 (PST), thirty-six <thirt...@live.co.uk> wrote:
>> There is no reason for the lowest spokes to stay tight, they do not
>> and can not contribute to the support of the wheel for their force is
>> in the same direction as the load upon the wheel and therefore
>> contributing to its load rather than working in opposition to the
>> load.
>
> At which point I hope it is obvious to all that 36 is either trolling,
> or (more likely, I think) actually does not understand that which he
> professes to be expert in.
Not from the bit you've quoted, that seems more-or-less right *taken in
isolation*.
On t'other hand, all the stuff about spoke crossings is, at best, trivial.
> In either case, the futility of extending
> the conversation further is obvious, I think.
It was obvious a long time ago. I must admit that I've been following
this thread with more than usual interest - mainly because, having
missed out on the beginning of the thread, I couldn't actually work out
what the two you were arguing about. That is, what the actual
difference in wheel building methods your arguments were meant to
advocate. Took me days to work it out ... the actual difference between
the methods must be infinitesimal. Mind you, I don't ever interlace...
well, hardly ever.
--
Andrew
thirty-six
> Ian Smith wrote:
He has no valid argument
On 14 Nov, 22:24, thirty-six <thirty-...@live.co.uk> wrote:
> Would you like to show how a spoke in tension within 15 deg of
> vertical is assisting in holding up the axle from the ground?
He cannot answer.
> The force is in exactly the same direction as the riding load, that of
> bringing together the hub and the ground. Having less of that is a
> good thing, so the bottom spokes should be releived as much as
> possible by correct construction method. This means that the spokes
> must become loose at some point to give the greatest load capacity
> without wheel buckling.
The differences in build are clearly evident when riding cobbles
without resort to measurement. Once you recognise the qualities it
is easy to see where they contribute in more usual riding.
The value of the interlace is to permit good elbow support of the
inner spoke by reduction of the angle to the flange and it also, when
elbows formed or tied and soldered, presents greater support by the
fore and aft spokes to the hub.
Ian Smith
> Ian Smith wrote:
> > On Sat, 14 Nov 2009 (PST), thirty-six <thirt...@live.co.uk> wrote:
> >> There is no reason for the lowest spokes to stay tight, they do not
> >> and can not contribute to the support of the wheel for their force is
> >> in the same direction as the load upon the wheel and therefore
> >> contributing to its load rather than working in opposition to the
> >> load.
> >
> > At which point I hope it is obvious to all that 36 is either trolling,
> > or (more likely, I think) actually does not understand that which he
> > professes to be expert in.
>
> Not from the bit you've quoted, that seems more-or-less right *taken in
> isolation*.
"there is no reason for the lowest spokes to stay tight"
That's a true statement, is it?
thirty-six
>
> "there is no reason for the lowest spokes to stay tight"
> That's a true statement, is it?
Absolute fact. It is preferable that a sixth of the rim is
permitted to deform towards the hub under load. The rim is not rigid
and should not be treated as such.
Clive George
news:e0fdc037-1808-4fe2...@z41g2000yqz.googlegroups.com...
And how would increasing spoke tension affect that? You may refer to Ian
Smith's FEA to help you with your answer if you wish.
thirty-six
> "thirty-six" <thirty-...@live.co.uk> wrote in message
Be specific, I dont follow your meaning, it is an ambiguous question..
What is 'that'?
Clive George
It's what your statement refers to.
"It is preferable that a sixth of the rim is permitted to deform towards the
hub under load. The rim is not rigid and should not be treated as such."
I included it in the quoted text so it would be obvious that it was that I
was referring to.
Now, having cleared up that bizarre confusion, how about answering my
question?
thirty-six
> "thirty-six" <thirty-...@live.co.uk> wrote in message
>
> news:6eb689c8-9142-408d...@z41g2000yqz.googlegroups.com...
> On 18 Nov, 14:25, "Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote:
>
>
>
> > "thirty-six" <thirty-...@live.co.uk> wrote in message
>
> >>news:e0fdc037-1808-4fe2...@z41g2000yqz.googlegroups.com...
> >> On 18 Nov, 07:36, Ian Smith <i...@astounding.org.uk> wrote:
>
> >> >> "there is no reason for the lowest spokes to stay tight"
> >> >> That's a true statement, is it?
>
> >> >Absolute fact. It is preferable that a sixth of the rim is
> >> >permitted to deform towards the hub under load. The rim is not rigid
> >> >and should not be treated as such.
>
> >> And how would increasing spoke tension affect that? You may refer to Ian
> >> Smith's FEA to help you with your answer if you wish.
>
> >Be specific, I dont follow your meaning, it is an ambiguous question..
>
> >What is 'that'?
>
> It's what your statement refers to.
>
> "It is preferable that a sixth of the rim is permitted to deform towards the
> hub under load. The rim is not rigid and should not be treated as such."
>
> I included it in the quoted text so it would be obvious that it was that I
> was referring to.
>
> Now, having cleared up that bizarre confusion, how about answering my
> question?
Which is what precisely? Use a single sentence, do not refer to
earlier posts. I'm tring to avoid a tangled web which you seem to
delight in constructing. It would be easier to ask the question
simply rather than play this charade.
Marc
and doesn't bother posting for a few weeks/months, until he thinks of a
new nym and comes out with new bollocks? At least that way the time when
he's not spewing bullshit comes around quicker!
Marc
As usual you are trying to avoid answering questions .
It would be easier to ask the question
> simply rather than play this charade.
It would be easier if you admitted that that you talk bollocks all the
time whether it's magic pixie dust on your wheels that make them go
faster , or descending at 60 mph regularly, or your dogmatic ideas of
clothing, nonstop, blinkered, slitted perspective , bollocks!
Naqerj
Now, now.
I said that "the bit you've quoted" (ie: the whole paragraph) was
"more-or-less right". So, no more running round with the goalposts, please.
--
Andrew
Ian Smith
> Ian Smith wrote:
> >> Ian Smith wrote:
> >>> On Sat, 14 Nov 2009 (PST), thirty-six <thirt...@live.co.uk> wrote:
> >>>>
> >>>> There is no reason for the lowest spokes to stay tight, they do not
> >>>> and can not contribute to the support of the wheel for their force is
> >>>> in the same direction as the load upon the wheel and therefore
> >>>> contributing to its load rather than working in opposition to the
> >>>> load.
> >>>
> >>> At which point I hope it is obvious to all that 36 is either
> >>> trolling, or (more likely, I think) actually does not understand
> >>> that which he professes to be expert in.
> >>
> >> Not from the bit you've quoted, that seems more-or-less right *taken in
> >> isolation*.
> >
> > "there is no reason for the lowest spokes to stay tight"
> > That's a true statement, is it?
>
> "more-or-less right". So, no more running round with the goalposts, please.
That was the key observation of the paragraph I quoted - the rest was
his explanation of why he believes that statement. The first,
fundamental, primary, key major point of what he said is "there is no
reason for the lower spokes to stay tight". That is his assertion,
the rest was justification.
You said that what he said is "more or less right".
Do you still claim that what he said is more or less right? You look
like you're now trying to build to a claim that the principal
assertion is wrong but the reasoning / justification is right. I
don't think that's a coherent view to hold (the opposite may be - you
can get a right answer with wrong reasoning, but you can't get the
wrong answer with correct reasoning).
Do you think it is true that "there is no reason for the lowest spokes
to stay tight"?
thirty-six
> Do you think it is true that "there is no reason for the lowest spokes
> to stay tight"?
What reason could there be?
Naqerj
Nice try, but it won't work. Just because you've rambled on for three
paragraphs before asking the same question again, doesn't stop it being
the same question. Funnily enough, my answer remains the same too.
Clearly, you just enjoy picking an argument just for the sake of it, but
you'll have to do it with somebody else. I was merely making the point
that, in order to convince the rest of us that 36 had no understanding
of the subject, you quoted a part of his argument that actually does
show some understanding. You can try as much you like to push the
argument in a completely different direction, but I won't be following
you there.
--
Andrew
Ian Smith
> Ian Smith wrote:
> >
> > Do you think it is true that "there is no reason for the lowest spokes
> > to stay tight"?
>
> Nice try, but it won't work. Just because you've rambled on for
> three paragraphs before asking the same question again, doesn't
> stop it being the same question. Funnily enough, my answer remains
> the same too.
Actually, although I have asked that question before, you haven't
actually answered it.
I asked it simply, and you obfuscated.
Since I was actually interested in the answer, I asked it again with
more explanation, detail, and background reasoning, and you have
obfuscated.
I consider it reasonable, having asked a simple question, to ask it
again if the person I ask doesn't answer. However, having asked
it twice, and having seen you dance around both times rather than
actually give a straight answer to the straight question, I recognise
that there is little point persevering.
As it stands, I _think_ you agree with 36 that there is no need for
spokes to stay tight under load, but since you won't answer the
question I'm still not completely sure.
> in order to convince the rest of us that 36 had no understanding of
> the subject, you quoted a part of his argument that actually does
> show some understanding.
No, I quoted a bit that shows how bad his understanding is.
If you think what I quoted shows some understanding, you are just as
misguided (or out of your depth) as he is. That your understanding is
just as bad as his, does not demonstrate his understanding to be any
better. It does not surprise me that more than one person is so
badly wrong about how a tensioned spoked wheel works.
Just as for him, there is no point discussing it further with you.
Marc
>
> Just as for him, there is no point discussing it further with you.
>
And I thought it was just me that thought the 33.4 was a moron!
thirty-six
> thirty-six <thirty-...@live.co.uk> considered Thu, 19 Nov 2009
> place to remove all lateral stability.
> It seems to me that losing lateral stability in any other part of the
> rim would be preferable to losing it the bit that is your only
> interface with the road.
Experience seems to hint at that only if you consider wheels which
have not had their interlace stabilized. Once this has been done by
either elbowing the interlace or tying and soldering the wheel,
responds in a more predictable manner.
Just as a hump backed bridge has an unsupported arch which functions
well, so does the wheel. It is the bridge abutments which ensure
stability of ots arch, and it is similar with the tension wheel.
There are of cause no abutments, so the rest of the wheel has to play
this role.
So stiffening up the rest of the wheel, with interlacing and locking
of the interlace, allows the supporting arch at the base of the wheel
to flex, assisting the tyre in tracking the road surface, while still
retaining overall wheel stability.
What seems to be particularly important is the way the locking of the
interlace assists in maintaining the height of the hub when the spokes
are more horizontal. The crossed spokes when locked together present
a more rigid structure because the spokes may not slide past each
other and this results in less sagging of the hub in the wheel. It
seems possible, although I have yet to verify it, that the very top
spokes will also lose some tension as do the lowest when the wheel is
loaded. I faintly recall this being told to me when I was a child
but am unable to recollect who or exactly what was said. There were
some good lightweight shops near to where I lived who made excellent
wheels and frames, thes places were an Aladdins cave to me and I got
into many conversations with the proprieters.
So anyway, losing stability in the other 3/4 of the wheel is like
building your hump backed bridge on a sand foundation. Not the way to
go.
thirty-six
> thirty-six <thirty-...@live.co.uk> considered Fri, 20 Nov 2009
> from the side?
>
> You seem to be confusing lateral with radial stability.
I'm not. I've forgotton what I've said now so i may repeat myself..
Friday night after all. The lateral stability of the arch is rem..
erm. totally dependent upon the abutments to the arch. The radial
compression of the arch is dependant upon the relative rigidity of the
abutments to the rigidity of the arch. The rigidity of the abutments
is increased by attention to the spoking arrangement.. the lateral
stability of the arch is increased by the lateral rigidity of the
abutments. Again attention to the spoking arrangement pays
divideneds.
Ignore the bottom of the wheel where the tyre is in contact with the
ground, this bit doesn't matter, its the bits either side that
matter. There is probably an ideal balance between rim suspension and
tyre contact area/length with quite wide margin for error. But the
upshot of it is, is that it is the arch as it leaves contactt with the
ground which is most important , the bit where the tyre contact patch
tapers off, the parralell portion of tread can be an area under s-
pokes without tensionacross the whole area without ill affect, unless
you flat suddenly for which you revert to a point contact and buckle a
super light wheel.
Naqerj
>
> Since I was actually interested in the answer,
I said I wouldn't but, if you really are interested in the answer...
There is no structural [1] reason for the spokes to remain tight as long
as they continue to behave elastically as a part of the wheel[2] as a
whole. In a normal [3] bicycle wheel this means that the spoke tension
can be infinitesimal without compromising the rigidity of the wheel.
Since the original question was expressed in terms that would not be
unambiguous to the determined nit-picker [4], I leave you to decide
whether that sums up as "yes" or "no".
[1] There are other reasons for it to need a certain amount of tension -
to provide enough friction to stop the nipples unscrewing, for instance.
[2] A normal [3] bicycle wheel is not constructed in a way that allows
spokes to act in compression so, when the tension drops to zero, the
spoke ceases to act as an elastic part of the wheel.
[3] Some children's cycles have wheels where the spokes can - and do -
act in compression.
[4] What qualifies as "tight", for example.
--
Andrew
Ian Smith
> Ian Smith wrote:
>
> > Since I was actually interested in the answer,
>
> I said I wouldn't but, if you really are interested in the answer...
>
> There is no structural [1] reason for the spokes to remain tight as
> long as they continue to behave elastically as a part of the
> wheel[2] as a whole. In a normal [3] bicycle wheel this means that
> the spoke tension can be infinitesimal without compromising the
> rigidity of the wheel.
So, there is no structural reason for the spokes to remain tight, as
long as they remain tight (since only by remaining tight will they
continue to behave elastically - if they are not tight they buckle).
> [2] A normal [3] bicycle wheel is not constructed in a way that
> allows spokes to act in compression so, when the tension drops to
> zero, the spoke ceases to act as an elastic part of the wheel.
Exactly.
So, you don't believe that what 36 said was basically correct. That
leaves me with a degree of confusion since I don't understand why you
said that what he said was basically correct, but at least we agree
about the need to, maintain tension in spoked bicycle wheels.
Thank you for the clarification of what you understand about wheels.
I am not sufficiently curious about your state of mind to pursue why
you said something you don't believe
thirty-six
You been on the whacky baccy?
Rob Morley
Naqerj <pat...@globalnet.co.invalid> wrote:
>
> [4] What qualifies as "tight", for example.
>
tight = under tension, slack = not under tension.
Just zis Guy, you know?
<pat...@globalnet.co.invalid> wrote:
>There is no structural [1] reason for the spokes to remain tight as long
>as they continue to behave elastically as a part of the wheel[2] as a
>whole. In a normal [3] bicycle wheel this means that the spoke tension
>can be infinitesimal without compromising the rigidity of the wheel.
If you are building cart wheels then I guess that's true, but for a
bicycle wheel with pneumatic tyres the spokes need to remain under at
least some residual tension at all times. Ian's finite element
analysis is pretty conclusive.
Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt
thirty-six
wrote:
It concludes you're a dumbass.
Just zis Guy, you know?
<thirt...@live.co.uk> wrote:
>It concludes you're a dumbass.
Oh good, abuse. I was wondering when that would be along, you've tried
everything else other than rational argument.
thirty-six
wrote:
> On Sun, 22 Nov 2009 10:11:33 -0800 (PST), thirty-six
>
> >It concludes you're a dumbass.
>
> Oh good, abuse. I was wondering when that would be along, you've tried
> everything else other than rational argument.
>
Rich
Just zis Guy, you know?
<thirt...@live.co.uk> wrote:
>Rich
Comfortably off, thanks. Probably because I use rational and
scientifically supportable arguments when building things.
thirty-six
wrote:
> On Sun, 22 Nov 2009 16:01:43 -0800 (PST), thirty-six
>
> >Rich
>
> Comfortably off, thanks. Probably because I use rational and
> scientifically supportable arguments when building things.
>
> Guy
> GPG public key athttp://www.chapmancentral.co.uk/pgp-public-key.txt
You really are a dick. There may be a conlusion made of an anaysis,
but an analysis is not conclusive.
Naqerj
> On Sat, 21 Nov 2009, Naqerj <pat...@globalnet.co.invalid> wrote:
>> Ian Smith wrote:
>>
>>> Since I was actually interested in the answer,
>> I said I wouldn't but, if you really are interested in the answer...
>>
>> There is no structural [1] reason for the spokes to remain tight as
>> long as they continue to behave elastically as a part of the
>> wheel[2] as a whole. In a normal [3] bicycle wheel this means that
>> the spoke tension can be infinitesimal without compromising the
>> rigidity of the wheel.
>
> So, there is no structural reason for the spokes to remain tight, as
> long as they remain tight (since only by remaining tight will they
> continue to behave elastically - if they are not tight they buckle).
Rubbish. A spoke won't buckle because it's not tight - there's no force
to buckle it. You have to go beyond the point of going slack and
actually apply some compression to it before it buckles. It will even
take some compression before it buckles - depending on what gauge and
how long it is.
>
>> [2] A normal [3] bicycle wheel is not constructed in a way that
>> allows spokes to act in compression so, when the tension drops to
>> zero, the spoke ceases to act as an elastic part of the wheel.
>
> Exactly.
>
> So, you don't believe that what 36 said was basically correct.
Wrong again. This is exactly why I didn't want to answer that question
out of context. The *whole paragraph* you quoted showed an
understanding of way a wheel works radially - it did not show
understanding (or misunderstanding) of the lateral behaviour of a wheel
because it said nothing about lateral behaviour. Seeing as the main
thing you two were squabbling about was lateral behaviour, that's why I
considered it particularly odd that you quoted that bit.
So there we are, back where we started. At which point I shall bow out
because I see no point at all in going round in a circle again.
--
Andrew
Naqerj
> On Sat, 21 Nov 2009 18:15:16 +0000
> Naqerj <pat...@globalnet.co.invalid> wrote:
>
>> [4] What qualifies as "tight", for example.
>>
> tight = under tension
>
Ah, but how much tension? That's the problem. For example having tight
hold of something is generally understood as implying a firmer grip than
just having hold of it.
> slack = not under tension.
That's less controversial
--
Andrew
Naqerj
> On Sat, 21 Nov 2009 18:15:16 +0000, Naqerj
> <pat...@globalnet.co.invalid> wrote:
>
>> There is no structural [1] reason for the spokes to remain tight as long
>> as they continue to behave elastically as a part of the wheel[2] as a
>> whole. In a normal [3] bicycle wheel this means that the spoke tension
>> can be infinitesimal without compromising the rigidity of the wheel.
>
> If you are building cart wheels then I guess that's true
The first sentence is true of most structures. The second sentence is
certainly not true of a cart wheel until you substitute 'compression'
for 'tension' ... though I've never built a cart wheel so I could be
wrong if they're not made in the way I think they are.
> but for a
> bicycle wheel with pneumatic tyres the spokes need to remain under at
> least some residual tension at all times.
But that residual tension can be so small as to be indistinguishable
from zero. If the strain on a wheel goes beyond the point where a few
spokes reach zero tension, the behaviour of the wheel changes because
the 'slack' spokes are no longer contributing to the rigidity of the
wheel. Nothing really bad happens at that point, though it's not an
ideal way to build a wheel.
Pneumatic tyres have nothing to do with it.
--
Andrew
Rob Morley
Naqerj <pat...@globalnet.co.invalid> wrote:
> Rob Morley wrote:
> > On Sat, 21 Nov 2009 18:15:16 +0000
> > Naqerj <pat...@globalnet.co.invalid> wrote:
> >
> >> [4] What qualifies as "tight", for example.
> >>
> > tight = under tension
> >
>
> Ah, but how much tension?
Enough that it doesn't go slack during the normal cycle of loading.
> That's the problem.
Why?
> For example having
> tight hold of something is generally understood as implying a firmer
> grip than just having hold of it.
Tight enough that you don't drop it under stress, just like the spoke
that doesn't go slack?
Ian Smith
> Ian Smith wrote:
> > On Sat, 21 Nov 2009, Naqerj <pat...@globalnet.co.invalid> wrote:
> >> Ian Smith wrote:
> >>
> >>> Since I was actually interested in the answer,
> >> I said I wouldn't but, if you really are interested in the answer...
> >>
> >> There is no structural [1] reason for the spokes to remain tight as
> >> long as they continue to behave elastically as a part of the
> >> wheel[2] as a whole. In a normal [3] bicycle wheel this means that
> >> the spoke tension can be infinitesimal without compromising the
> >> rigidity of the wheel.
> >
> > So, there is no structural reason for the spokes to remain tight, as
> > long as they remain tight (since only by remaining tight will they
> > continue to behave elastically - if they are not tight they buckle).
>
> Rubbish. A spoke won't buckle because it's not tight - there's no force
> to buckle it. You have to go beyond the point of going slack and
> actually apply some compression to it before it buckles. It will even
> take some compression before it buckles - depending on what gauge and
> how long it is.
It won't buckle if it has exactly, perfectly zero load, no. However,
that's a pointless thing to say. An exactly, perfectly straight strut
won't buckle either, but I was confining myself to discussion of
behaviours exhibited in the real world. A spoke with a tiny
compressive load will buckle.
> >> [2] A normal [3] bicycle wheel is not constructed in a way that
> >> allows spokes to act in compression so, when the tension drops to
> >> zero, the spoke ceases to act as an elastic part of the wheel.
> >
> > Exactly.
> >
> > So, you don't believe that what 36 said was basically correct.
>
> Wrong again. This is exactly why I didn't want to answer that question
> out of context. The *whole paragraph* you quoted showed an
> understanding of way a wheel works radially
Nonsense.
He's forgotten all sorts of things radially - for example he rages on
about how everyone else is treating the rim as rigid and it must be
allowed to deflect inwards, then he says exactly the wrong thing -
that loads distribute round the rim to the top - demonstrating that
actually, he is assuming the rim is rigid.
The paragraph in question he starts with a wrong statement that there
is no reason for spokes to remain tight. In a bicycle wheel. That's
rubbish - if they don't, they buckle and if they buckle wheel failure
is close behind. (Your argument above is irrelevant because I don't
believe you can build a wheel that has just the right tension that
spokes lose tension but the rim doesn't apply any significant
compression.)
The rest of his paragraph was his reasoning for the opening assertion.
As previously noted, it is not possible to reach wrong conclusion
from correct reasoning.
> Seeing as the main
> thing you two were squabbling about was lateral behaviour, that's why I
> considered it particularly odd that you quoted that bit.
Nonsense. I am disagreeing about the behaviour of spoked wheels. I
am not confined to lateral behaviour. Indeed, I would say that 26's
main arguments are about radial behaviour - that's what he says
everyone but him has forgotten (just before he demonstrates that if he
hasn't forgotten it, he doesn't know how to handle it).
So, we are back to 36 being very wrong about wheel behaviour, and you
saying he has demonstrated good understanding.
thirty-six
> On Mon, 23 Nov 2009 21:50:20 +0000, Naqerj <pat...@globalnet.co.invalid> wrote:
>
> > Rubbish. A spoke won't buckle because it's not tight - there's no force
> > to buckle it. You have to go beyond the point of going slack and
> > actually apply some compression to it before it buckles. It will even
> > take some compression before it buckles - depending on what gauge and
> > how long it is.
>
> It won't buckle if it has exactly, perfectly zero load, no. However,
> that's a pointless thing to say. An exactly, perfectly straight strut
> won't buckle either, but I was confining myself to discussion of
> behaviours exhibited in the real world. A spoke with a tiny
> compressive load will buckle.
The buckling of a tension spoke is irrelevant, if it was of any
significance the rim would already likely have suffered permanent
deformation. The drilling at the hub and the slip joint at the rim
mean that getting a spoke into compression is difficult unless bloody
minded.
> He's forgotten all sorts of things radially - for example he rages on
> about how everyone else is treating the rim as rigid and it must be
> allowed to deflect inwards, then he says exactly the wrong thing -
> that loads distribute round the rim to the top - demonstrating that
> actually, he is assuming the rim is rigid.
You must be confusing me with someone else. I state that the rim is
constrained, by the spokes, from spreading. This does make the rim
effectively stiffer. This is why spokes need to be considered with
the rim rigidity as there gauge, length and number all affect the rim.
>
> The paragraph in question he starts with a xxxx [CORRECT}statement that there
> is no reason for spokes to remain tight. In a bicycle wheel. That's
> rubbish - if they don't, they buckle and if they buckle wheel failure
> is close behind.
NOT TRUE. Rattling spokes are simply annoying. A buckled spoke
canniot cause wheel failure.
> (Your argument above is irrelevant because I don't
> believe you can build a wheel that has just the right tension that
> spokes lose tension but the rim doesn't apply any significant
> compression.)
Huh? All loading is significant. The rim is put under bending by
the riding load. This is significant, that is why we have tension
spokes, to reduce the rim deformation to a manageable level and to
locate the central rotating bearing.
> Nonsense. I am disagreeing about the behaviour of spoked wheels. I
> am not confined to lateral behaviour. Indeed, I would say that 26's
> main arguments are about radial behaviour - that's what he says
> everyone but him has forgotten (just before he demonstrates that if he
> hasn't forgotten it, he doesn't know how to handle it).
Correctly controlling radial behaviour results in improved lateral
behaviour of a rim under greater loads.