Wheelbuilding wisdom for the novice

mrbubl said:

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

Quoted message said:

I have done the requisite stress reliefs as recommended but it would

appear

Quoted message said:

after a hundred miles or so the wheel still needs (and benenfits from) a "touch up" with the spoke
wrench. Is the "normal" or am I not doing something right?

The most common reasons for a wheel going out of true are:

1) Spokes too loose or uneven tension
2) Spoke windup coming unwound
3) Damage to rim from hitting a pot hole, etc.

As described in "The Bicycle Wheel," the test for tightness is to stress relieve and when the wheel
deveops waves afterward, it's too tight. Back off
4/4 to 1/2 turn all around and try again.

Art Harris

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

Quoted message said:

My personal experience to date is a whopping 4 wheels, all road, all 3 cross, all clinchers. I have
invested in the printed wisdom of Guru Jobst and the electronic wisdom of Gurus Art, Sheldon, Peter
et al....... My query is when a wheel is round and true and without the benefit of a tensionmeter,
how tight is TOO TIGHT on the spokes?

This is covered in Jobst' book. Too tight is when the wheel taco's when you stress relieve it.

Quoted message said:

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benenfits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

If you are getting spoke wind up, that can cause your wheel to go untrue after riding it. Too low a
tension will also cause the problem you are having.

Quoted message said:

Is this just a right of passage of wheelbuilding and one of the skills that gets better with age
and trial?

With more practice, you get faster, not necessarily better.
-----------------
Alex __O _-\<,_ (_)/ (_)

I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel as
normal. Then to encourage the correct spoke bend take an aluminum punch and hammer the spoke, force
it into the flange at the hub. Outside spokes only. Check tension again Most wheels take another 1/2
to 1 full turn on the threads Install the tire to proper pressure. Check tension again Most wheels
take another 1/2 to 1 full turn at the threads Speedy

mrbubl said:

My personal experience to date is a whopping 4 wheels, all road, all 3 cross, all clinchers. I
have invested in the printed wisdom of Guru Jobst and the electronic wisdom of Gurus Art, Sheldon,
Peter et al.......

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benenfits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

Is this just a right of passage of wheelbuilding and one of the skills that gets better with age
and trial?

michael

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

Quoted message said:

My personal experience to date is a whopping 4 wheels, all road, all 3 cross, all clinchers. I
have invested in the printed wisdom of Guru Jobst and the electronic wisdom of Gurus Art, Sheldon,
Peter et al.......

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

If you did read JB's book you wouldn't ask this question.

Quoted message said:

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benenfits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

This seems to indicate the spokes are too loose.

-Amit

mrbubl said:

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

As someone else said, it'll taco when you try to stress-relieve. Startling thing to happen, but
salvagable.

Quoted message said:

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benenfits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

Something is not right. Spend more time making sure tension is even before worrying about
true. A wheel can look true on the stand with a sequence of spokes too loose then too tight.
This is especially true with stronger rims that average out the unevenness. But it will go out
of true with use.

--

David L. Johnson

__o | "What am I on? I'm on my bike, six hours a day, busting my ass. _`\(,_ | What are you on?"
--Lance Armstrong (_)/ (_) |

"mrbubl" <[email hidden]> wrote in message news:kHBIa.56202>

Quoted message said:

Is this just a right of passage of wheelbuilding and one of the skills that gets better with age
and trial?

This is right out of the 1980's, we haven't competed on those things in decades!

Get yourself three or four sets of something like Mavic Cosmic Carbone SSC or Spinergy Tilium
Carbons and you are set for the whole season.

Michael Bubl? said:

My personal experience to date is a whopping 4 wheels, all road, all 3 cross, all clinchers. I
have invested in the printed wisdom of Guru Jobst and the electronic wisdom of Gurus Art, Sheldon,
Peter et al.......

Quoted message said:

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

"tensiometer"

I see you didn't get the book or at least read it. There are probably few technical questions you
could devise that are not addressed there besides the explanation of what a tensiometer is and
how it works.

Quoted message said:

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benefits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

Your wheel is too loose. Read the book!

Quoted message said:

Is this just a right of passage of wheelbuilding and one of the skills that gets better with age
and trial?

You can do it right the first time. Many people have.

Jobst Brandt [email hidden] Palo Alto CA

S? Delaire said:

I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel
as normal.

They do that from tension all by themselves, the highest tension a spoke carries is when the wheel
is unloaded. Therefore you needn't worry about seating, especially after stress relieving, probably
the most important part of wheel building.

Quoted message said:

Then to encourage the correct spoke bend take an aluminum punch and hammer the spoke, force it
into the flange at the hub. Outside spokes only.

Don't do this! It damages trueness and integrity of hub flanges.

Quoted message said:

Check tension again Most wheels take another 1/2 to 1 full turn on the threads Install the tire to
proper pressure.

Quoted message said:

Check tension again Most wheels take another 1/2 to 1 full turn at the threads.

This may apply to your M/C but not to bicycle wheels.

Jobst Brandt [email hidden] Palo Alto CA

S. Delaire 'Rotatorrecumbent said:

I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel as
normal. Then to encourage the correct spoke bend take an aluminum punch and hammer the spoke,
force it into the flange at the hub. Outside spokes only.

I wouldn't do this. If you stress relieve using a screw driver handle or something similar, it'll
seat the spokes. We're not talking big motorcycle spokes and rims here!

Quoted message said:

Check tension again Most wheels take another 1/2 to 1 full turn on the threads Install the tire
to proper pressure. Check tension again Most wheels take another 1/2 to 1 full turn at the
threads Speedy

mrbubl said:

My personal experience to date is a whopping 4 wheels, all road, all 3 cross, all clinchers. I
have invested in the printed wisdom of Guru Jobst and the electronic wisdom of Gurus Art, Sheldon,
Peter et al.......

My query is when a wheel is round and true and without the benefit of a tensionmeter, how tight is
TOO TIGHT on the spokes?

I have done the requisite stress reliefs as recommended but it would appear after a hundred miles
or so the wheel still needs (and benenfits from) a "touch up" with the spoke wrench. Is the
"normal" or am I not doing something right?

Is this just a right of passage of wheelbuilding and one of the skills that gets better with age
and trial?

michael

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

Quoted message said:

S? Delaire said:

I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel
as normal.

They do that from tension all by themselves, the highest tension a spoke carries is when the wheel
is unloaded.

Huh? I would think the spokes at the top of the wheel rotation would have higher tension when loaded
than they do unloaded. I can see why the bottoms might not carry any less load than their pre-load
(assuming no elongation of the uppers), but the uppers would have to carry more. If they don't, then
what is supporting the additional axle weight?

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

David Kerber said:

Quoted message said:

Quoted message said:

I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel
as normal.

Quoted message said:

Quoted message said:

They do that from tension all by themselves, the highest tension a spoke carries is when the
wheel is unloaded.

Quoted message said:

Huh? I would think the spokes at the top of the wheel rotation would have higher tension when
loaded than they do unloaded. I can see why the bottoms might not carry any less load than their
pre-load (assuming no elongation of the uppers), but the uppers would have to carry more. If they
don't, then what is supporting the additional axle weight?

Wire spoked wheels do not work the way we were led to believe for the past century although I'm sure
someone in the 19th century analyzed it and understood it, back in the days when the bicycle was the
state of the technical art. However, the book in question brought all that up to date for us
come-latelys and may be worth your perusal.

You can assure yourself of the load distributions by plucking the same spoke (for accurate tone
repetition) in the front wheel when it is at the top of the wheel and at the bottom, before and
after you put your full weight on the handlebars. It is best to have an assistant for this. Just in
case it isn't obvious. The higher the tone the higher the tension.

avocet.comwheelbook.htmlOpen ↗

Jobst Brandt [email hidden] Palo Alto CA

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

Quoted message said:

David Kerber said:

Quoted message said:

> I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
> builder. Spokes "settle" at the bend were the go through the hub. First build and tension
> wheel as normal.

Quoted message said:

Quoted message said:

They do that from tension all by themselves, the highest tension a spoke carries is when the
wheel is unloaded.

Quoted message said:

Huh? I would think the spokes at the top of the wheel rotation would have higher tension when
loaded than they do unloaded. I can see why the bottoms might not carry any less load than their
pre-load (assuming no elongation of the uppers), but the uppers would have to carry more. If
they don't, then what is supporting the additional axle weight?

Wire spoked wheels do not work the way we were led to believe for the past century although I'm
sure someone in the 19th century analyzed it and understood it, back in the days when the bicycle
was the state of the technical art. However, the book in question brought all that up to date for
us come-latelys and may be worth your perusal.

You can assure yourself of the load distributions by plucking the same spoke (for accurate tone
repetition) in the front wheel when it is at the top of the wheel and at the bottom, before and
after you put your full weight on the handlebars. It is best to have an assistant for this. Just
in case it isn't obvious. The higher the tone the higher the tension.

Instead of trying this on a normal wheel with lots of spokes, think about a 4-spoke wheel, with the
wheel turned so that one of them is straignt up and down. If they are pre-tensioned to 200lbf, and
you then set 200lbs of bike and rider on them, the tension in the top spoke MUST increase by 200lbf
total (front and rear combined). It will likely be more in the rear than the front, but it the
combined increase must equal the total weight of the load. A simple statics calculation will show
you that. The interesting part of this calculation is that if the spokes don't stretch and the wheel
doesn't distort, the tension in the bottom and side-facing spokes doesn't change at all.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

David Kerber said:

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

Quoted message said:

David Kerber said:

>>I haven't read the book, this might be covered there. A trick learned from a motorcycle wheel
>>builder. Spokes "settle" at the bend were the go through the hub. First build and tension wheel
>>as normal.
>
>They do that from tension all by themselves, the highest tension a spoke carries is when the
>wheel is unloaded.

Huh? I would think the spokes at the top of the wheel rotation would have higher tension when
loaded than they do unloaded. I can see why the bottoms might not carry any less load than their
pre-load (assuming no elongation of the uppers), but the uppers would have to carry more. If they
don't, then what is supporting the additional axle weight?

Wire spoked wheels do not work the way we were led to believe for the past century although I'm
sure someone in the 19th century analyzed it and understood it, back in the days when the bicycle
was the state of the technical art. However, the book in question brought all that up to date for
us come-latelys and may be worth your perusal.

You can assure yourself of the load distributions by plucking the same spoke (for accurate tone
repetition) in the front wheel when it is at the top of the wheel and at the bottom, before and
after you put your full weight on the handlebars. It is best to have an assistant for this. Just
in case it isn't obvious. The higher the tone the higher the tension.

Instead of trying this on a normal wheel with lots of spokes, think about a 4-spoke wheel, with
the wheel turned so that one of them is straignt up and down. If they are pre-tensioned to 200lbf,
and you then set 200lbs of bike and rider on them, the tension in the top spoke MUST increase by
200lbf total (front and rear combined). It will likely be more in the rear than the front, but it
the combined increase must equal the total weight of the load. A simple statics calculation will
show you that. The interesting part of this calculation is that if the spokes don't stretch and
the wheel doesn't distort, the tension in the bottom and side-facing spokes doesn't change at all.

Holy moly, you've invented anti-gravity!

Firstly, you've started with an incorrect assumption, that the rim is infinitely stiff as compared
to the spokes. In actuality, the radial stiffness of the rim is much less than the radial stiffness
of the spokes. So when you apply a load to the wheel, the bottom of the rim will easily bend inward
allowing the bottom spokes to absorb the load, and very little of the load will be allowed to be
transferred to the top of the wheel.

But even if the rim were infinitely stiff, you've still got it all wrong. I think you'll agree that
as you tension the spokes, they will elastically stretch in proportion. According to you, the top
spokes increase tension, but the bottom spokes don't. Therefore the top spokes will stretch but the
bottom spokes won't. This means that when you apply a load to the hub, the top of the rim will move
upward (as the top spokes stretch from extra tension), but the hub won't get any closer to the
ground (because the bottom spokes don't change tension). You've just invented anti-gravity!

Before you get yourself further tripped up in half thought-out theory, I really suggest you try the
spoke plucking experiment mentioned above. It can be very illuminating.

By the way here's a hint: There are two ways to counter a load applied to the wheel's hub - you can
either increase the tension in the top spokes, or decrease the tension in the bottom spokes. After
you do the spoke plucking experiment, you'll know which one happens in a real wheel.

Mark McMaster [email hidden]

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

...

Quoted message said:

Quoted message said:

Instead of trying this on a normal wheel with lots of spokes, think about a 4-spoke wheel, with
the wheel turned so that one of them is straignt up and down. If they are pre-tensioned to
200lbf, and you then set 200lbs of bike and rider on them, the tension in the top spoke MUST
increase by 200lbf total (front and rear combined). It will likely be more in the rear than the
front, but it the combined increase must equal the total weight of the load. A simple statics
calculation will show you that. The interesting part of this calculation is that if the spokes
don't stretch and the wheel doesn't distort, the tension in the bottom and side-facing spokes
doesn't change at all.

Holy moly, you've invented anti-gravity!

Firstly, you've started with an incorrect assumption, that the rim is infinitely stiff as compared
to the spokes. In

That was only a simplifying assumption for illustration purposes. I am well aware that it is not the
case in real life.

Quoted message said:

actuality, the radial stiffness of the rim is much less than the radial stiffness of the spokes.
So when you apply a load to the wheel, the bottom of the rim will easily bend inward allowing the
bottom spokes to absorb the load, and very little of the load will be allowed to be transferred to
the top of the wheel.

SOME of it must be transferred, because the total vertical load on the axle must increast to equal
the total weight of the load. That difference is spread out among lots of spokes, so the change in
tension in any one spoke is probably only a few pounds. That's why you don't hear it.

Quoted message said:

But even if the rim were infinitely stiff, you've still got it all wrong. I think you'll agree
that as you tension the spokes, they will elastically stretch in proportion. According to you, the
top spokes increase tension, but the bottom spokes don't. Therefore the top spokes will stretch

I didn't say they didn't stretch; I said that *If you make the simplifying assumption that nothing
deformed* then the tension in the bottom wouldn't change. That is obviously not a real-life
assumption. However, I still maintain the the tension in the top spokes MUST increase to handle the
added load. Draw a simple free body diagram with a 4-spoke wheel and work out the calculations. As
you said below, if you take the real life case in which the spokes and wheel deform under load, then
the increase in tension in the upper is smaller, because it is partly counter-acted by the decrease
in the lowers, but it CANNOT fully cancel out, or there would be nothing to support the added load
on the axle.

Quoted message said:

Before you get yourself further tripped up in half thought-out theory, I really suggest you try
the spoke plucking experiment mentioned above. It can be very illuminating.

It wouldn't surprise me a bit if you couldn't tell the difference in tension by the sound of a
plucked spoke, especially in a high spoke- count wheel (because the load is distributed over so many
spokes), but it MUST be there, and with a sensitive enough tensionometer, you could measure it. Do
the calculations!!!

....

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

David Kerber said:

... I didn't say they didn't stretch; I said that *If you make the simplifying assumption that
nothing deformed* then the tension in the bottom wouldn't change. That is obviously not a
real-life assumption....

I was not aware that it was possible to analyze a statically indeterminate system without taking the
stiffness of the structural members into account. Or maybe the entire applied science/engineering
profession is wrong on a fundamental issue?

Tom Sherman - Quad Cities USA (Illinois side)

David Kerber said:

Quoted message said:

Before you get yourself further tripped up in half thought-out theory, I really suggest you try
the spoke plucking experiment mentioned above. It can be very illuminating.

It wouldn't surprise me a bit if you couldn't tell the difference in tension by the sound of a
plucked spoke, especially in a high spoke- count wheel (because the load is distributed over so
many spokes), but it MUST be there, and with a sensitive enough tensionometer, you could measure
it. Do the calculations!!!

Isn't it wild, how someone will argue at length (and talk about how small the difference probably
is) rather than take the 5 minutes to do the spoke-plucking test and see (hear) for themselves.

Tom Ace

David Kerber said:

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

...

Quoted message said:

Quoted message said:

Instead of trying this on a normal wheel with lots of spokes, think about a 4-spoke wheel, with
the wheel turned so that one of them is straignt up and down. If they are pre-tensioned to
200lbf, and you then set 200lbs of bike and rider on them, the tension in the top spoke MUST
increase by 200lbf total (front and rear combined). It will likely be more in the rear than the
front, but it the combined increase must equal the total weight of the load. A simple statics
calculation will show you that. The interesting part of this calculation is that if the spokes
don't stretch and the wheel doesn't distort, the tension in the bottom and side-facing spokes
doesn't change at all.

Holy moly, you've invented anti-gravity!

Firstly, you've started with an incorrect assumption, that the rim is infinitely stiff as compared
to the spokes. In

That was only a simplifying assumption for illustration purposes. I am well aware that it is not
the case in real life.

Quoted message said:

actuality, the radial stiffness of the rim is much less than the radial stiffness of the spokes.
So when you apply a load to the wheel, the bottom of the rim will easily bend inward allowing the
bottom spokes to absorb the load, and very little of the load will be allowed to be transferred to
the top of the wheel.

SOME of it must be transferred, because the total vertical load on the axle must increast to equal
the total weight of the load. That difference is spread out among lots of spokes, so the change in
tension in any one spoke is probably only a few pounds. That's why you don't hear it.

Quoted message said:

But even if the rim were infinitely stiff, you've still got it all wrong. I think you'll agree
that as you tension the spokes, they will elastically stretch in proportion. According to you, the
top spokes increase tension, but the bottom spokes don't. Therefore the top spokes will stretch

I didn't say they didn't stretch; I said that *If you make the simplifying assumption that nothing
deformed* then the tension in the bottom wouldn't change. That is obviously not a real-life
assumption. However, I still maintain the the tension in the top spokes MUST increase to handle
the added load. Draw a simple free body diagram with a 4-spoke wheel and work out the
calculations. As you said below, if you take the real life case in which the spokes and wheel
deform under load, then the increase in tension in the upper is smaller, because it is partly
counter-acted by the decrease in the lowers, but it CANNOT fully cancel out, or there would be
nothing to support the added load on the axle.

Quoted message said:

Before you get yourself further tripped up in half thought-out theory, I really suggest you try
the spoke plucking experiment mentioned above. It can be very illuminating.

It wouldn't surprise me a bit if you couldn't tell the difference in tension by the sound of a
plucked spoke, especially in a high spoke- count wheel (because the load is distributed over so
many spokes), but it MUST be there, and with a sensitive enough tensionometer, you could measure
it. Do the calculations!!!

The calculations will depend on what is assumed about the relative stiffness of the spokes vs. the
rim. If we make the assumption that the rim is infinitely stiff and the spokes are elastic (as Mark
pointed out this is a very poor assumption for a real wheel), then your 4-spoke wheel looks like a
rigid hoop connected to the hub with strong 'rubber-band' spokes. The rubber bands each have a
pre-load tension of 200 lbs-f, so the hub feels a pull of 200 lbs downward from the bottom rubber
band, a force of 200 lbs upward from the top rubber band, and cancelling 200 lb forces forward and
backward by the two side rubber bands. Now the hub axle is pushed down by the weight of rider + bike
in the amount of 100 lbs-f. With a rigid hoop, the rubber band on the bottom will get shorter and
have a reduced tension while the rubber band on the top will be stretched by an equal amount and
have an increased tension. The two side rubber bands will only have an insignificant increase in
their lengths, so they'll have very slight tension increases which we'll ignore. If the bottom and
top rubber bands have the same spring constant, the reduction of tension from the bottom one will be
equal to the increase of tension in the top and the sum of these two effects must balance the
downward force on the hub of 100 lbs-f. So the bottom spoke sees a reduction of its preload from 200
lbs-f to 150 lbs-f, the top spoke sees an increase from 200 lbs-f to 250 lbs-f and the net force on
the hub is balanced as expected: 250 up - 150 down - 100 down from rider+bike = 0 net force.

The other extreme is that the rim is very flexible and the spokes are more rigid. In this case when
the wheel is pushed down by the weight of bike+rider, the bottom of the rim deforms while the rest
of the rim maintains its shape. In this case the bottom spoke sees a decrease in tension but the top
and side spokes will have no change. If the force from the weight of bike+rider is 100 lbs, then the
tension in the bottom spoke must decrease by 100 lbs-f to balance it and therefore change from the
initial preload value of 200 to 100 lbs-f while the tension in the top spoke remains at 200 lbs-f.
The net forces on the hub are still properly balanced: 200 up - 100 down - 100 down from bike+rider
= 0 net force.

In the case of my actual bicycle wheels with a lightweight rim and 36 14 gauge spokes almost all of
the radial rigidity comes from the spokes and very little from the rim (the rim alone would
immediately collapse under my weight). Therefore it closely matches the second scenario and I'd
expect almost no change in the tension of the top spokes when the wheel is loaded.

David Kerber said:

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

...

Quoted message said:

Quoted message said:

Instead of trying this on a normal wheel with lots of spokes, think about a 4-spoke wheel, with
the wheel turned so that one of them is straignt up and down. If they are pre-tensioned to
200lbf, and you then set 200lbs of bike and rider on them, the tension in the top spoke MUST
increase by 200lbf total (front and rear combined). It will likely be more in the rear than the
front, but it the combined increase must equal the total weight of the load. A simple statics
calculation will show you that. The interesting part of this calculation is that if the spokes
don't stretch and the wheel doesn't distort, the tension in the bottom and side-facing spokes
doesn't change at all.

Holy moly, you've invented anti-gravity!

Firstly, you've started with an incorrect assumption, that the rim is infinitely stiff as compared
to the spokes. In

That was only a simplifying assumption for illustration purposes. I am well aware that it is not
the case in real life.

Quoted message said:

actuality, the radial stiffness of the rim is much less than the radial stiffness of the spokes.
So when you apply a load to the wheel, the bottom of the rim will easily bend inward allowing the
bottom spokes to absorb the load, and very little of the load will be allowed to be transferred to
the top of the wheel.

SOME of it must be transferred, because the total vertical load on the axle must increast to equal
the total weight of the load. That difference is spread out among lots of spokes, so the change in
tension in any one spoke is probably only a few pounds. That's why you don't hear it.

Quoted message said:

But even if the rim were infinitely stiff, you've still got it all wrong. I think you'll agree
that as you tension the spokes, they will elastically stretch in proportion. According to you, the
top spokes increase tension, but the bottom spokes don't. Therefore the top spokes will stretch

I didn't say they didn't stretch; I said that *If you make the simplifying assumption that nothing
deformed* then the tension in the bottom wouldn't change. That is obviously not a real-life
assumption. However, I still maintain the the tension in the top spokes MUST increase to handle
the added load. Draw a simple free body diagram with a 4-spoke wheel and work out the
calculations. As you said below, if you take the real life case in which the spokes and wheel
deform under load, then the increase in tension in the upper is smaller, because it is partly
counter-acted by the decrease in the lowers, but it CANNOT fully cancel out, or there would be
nothing to support the added load on the axle.

The tension in the top spokes does increase slightly - but not for the reasons you think. If you
look closely, you'll see that as the rim flattens out at the very bottom of the wheel, the radius of
the rim around the rest of the wheel (including the sides and top) increases slightly. It is this
affect, and not the transfer of the external load to the top of the wheel, that accounts for the
increase in tension in spokes on the sides and top of the wheel.

Quoted message said:

Quoted message said:

Before you get yourself further tripped up in half thought-out theory, I really suggest you try
the spoke plucking experiment mentioned above. It can be very illuminating.

It wouldn't surprise me a bit if you couldn't tell the difference in tension by the sound of a
plucked spoke, especially in a high spoke- count wheel (because the load is distributed over so
many spokes), but it MUST be there, and with a sensitive enough tensionometer, you could
measure it.

This is starting to become tiresome. Theory and calculations mean nothing if they don't jibe with
reality. Doing the spoke plucking experiment will show just what the reality is when it comes to the
tension changes in a wheel to support a load. You have obviously not done the experiment, or else
you wouldn't continue on this path.

Quoted message said:

Do the calculations!!!

The calculations have been done many times. First, in "The Bicycle Wheel", by Jobst Brandt, and then
by others. All analyses agree that there is very little change in tension in the top spokes, and
that the total increase in tension in the top spokes don't even come close to equaling the load on
the wheel. Here are a few analyses:

rose-hulman.eduHartz.pdfOpen ↗

achrn.demon.co.ukwheelOpen ↗

Mark McMaster [email hidden]

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

Quoted message said:

David Kerber said:

... I didn't say they didn't stretch; I said that *If you make the simplifying assumption that
nothing deformed* then the tension in the bottom wouldn't change. That is obviously not a
real-life assumption....

I was not aware that it was possible to analyze a statically indeterminate system without taking
the stiffness of the structural members into account. Or maybe the entire applied
science/engineering profession is wrong on a fundamental issue?

For a detailed analysis, of course not. However, simplifying assumptions like this are valid and
commonly used techniques to get a feel for the direction and rough magnitude of the effects
under study.

--
David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
it's morning".

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