Any validity to these assertions?

Jay Hill writes:

[as a cause for broken spokes]

Quoted message said:

1) Do not mount a bicycle like a horse, by putting a foot in the left pedal and swinging the right
leg over the seat to the other pedal.

Please explain how this can have any effect considering that I can coast down a road standing on one
pedal while leaning as far out to one side as I like with no spoke failures. Noting that spoke
failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a foreign
object snagged a spoke, what effect does mounting the bicycle have on the endurance of spokes?

This is one of the most bizarre claims I have heard about the spoked bicycle wheel. Having never
heard it before, I wonder what sort of underground passes along such myth and lore.

Jobst Brandt [email hidden]

22 Jan 2004 20:19:31 -0500 Sheldon Brown said:

This doesn't bother the bottom bracket, but is very stressful to the wheels. Bicycle wheels are
very strong against radial loads, but quite weak against side loads.

Sorry Sheldon, but I have to take issue with you on this one. I agree that side loads on the bike
certainly do put some of the most extreme loads on the spokes, but it is easy to ride along in a
straight line while tilting the bike over way past the spoke angle. I've done this a number of
times, just to see if it causes any problems and it never has.

I also commonly mount my bike single sided, swinging my right leg over the frame after I'm under
way. I often dismount the same way, coasting the last 30 yards on one side of the bike.

I haven't had a random broken spoke in about 35 years, since I got rid of that Normandy rear
hub with the left flange offset all the way to the outside, so far that I couldn't put any
tension in those spokes. That was an awful hub, but it taught me an important lesson: Loose
spokes are a problem.

-
-----------------------------------------------
Jim Adney [email hidden] Madison, WI 53711 USA
-----------------------------------------------

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

Quoted message said:

Jay Hill writes:

[as a cause for broken spokes]

Quoted message said:

1) Do not mount a bicycle like a horse, by putting a foot in the left pedal and swinging the
right leg over the seat to the other pedal.

Please explain how this can have any effect considering that I can coast down a road standing on
one pedal while leaning as far out to one side as I like with no spoke failures. Noting that spoke
failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a foreign
object snagged a spoke, what effect does mounting the bicycle have on the endurance of spokes?

This is one of the most bizarre claims I have heard about the spoked bicycle wheel. Having never
heard it before, I wonder what sort of underground passes along such myth and lore.

Jobst Brandt [email hidden]

Dear Jobst,

I expect that you're right, but now I want to know what actually happens to the spokes when a rider
stands on one pedal and leans way over while coasting straight down the road.

As the pre-tensioned left and right side spokes pass under the axle, they lose tension, right?

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

I looked at "The Bicycle Wheel," where you go over lateral stiffness and later showed your testing
rig for demonstrating that tying and soldering are merely decorative, but I'm not sure how to apply
what you wrote.

I think that the left side spokes should gain tension with the wheel leaning over to the right, but
do they all gain tension equally? Or does the force act only through the rim just above the contact
patch? Either way, does this gain in tension cancel out the loss of tension on the left side spokes
rolling under the axle?

Similarly, do all the right-side spokes lose tension because the wheel is leaning to the right, or
just the ones on the bottom? And could the bottom ones get into trouble because the loss in tension
from the sideways leaning is added to the loss in tension from the normal load?

Here's a crude view from the rear of what I'm wondering about: top rim do all left-side / / spokes
gain tension / / due to lean --> / / <--do all right-side spokes or just a few / / lose tension due
to lean? lower left-side / / or just a few lower right-side spokes? spokes? left hub right / / can
left-side / / tension gain / / cancel normal / / <--can right-side tension loss lowermost-spoke / /
plus normal lowermost-spoke tension loss tension loss? / / get out of hand? rim -------------ground
and contact patch

I suspect that even with a heavy rider the sideways load is much less than the vertical load, but
I'm still curious about what the leaning does to the spoke tension--do all spokes on one side change
tension equally, or just the ones down near the contact patch?

Carl Fogel

may have said:

I enjoy horsemounting because it's fun, easy, fast, natural (to me).

Otherwise it's clomp, clomp, straddle, step & go -- mechanical and without grace. 'jus my opinion.

Mileages vary.

For me, the right leg goes over the top onto the pedal (which has been brought to the 1 o'lock
position beforehand) and then the takeoff proceeds as the left foot leaves the ground. (Conventional
pedals, no clips or cleats.)

I've done a horse-mount sometimes, but I just prefer the other way. Everyone finds the way that
work for them.

--
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it's also possible that I'm busy.
Words processed in a facility that contains nuts.

On Sun, 25 Jan 2004 01:08:23 GMT, [email hidden] may
have said:

[snippage]

Quoted message said:

This is one of the most bizarre claims I have heard about the spoked bicycle wheel. Having never
heard it before, I wonder what sort of underground passes along such myth and lore.

Probably the same variety that propagates urban legends of the more common sorts, like the currently-
popular "Terrorists may be at your door in UPS uniforms" scaremail.

I struck me (after the fact) that the whole "mounting wrong can cause spoke breakage" assertion had
an apparent flaw; if the side forces were that large, would it not be true that people would be
turning their wheels into tacos by that practice? Yet they are not.

--
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Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.

Werehatrack said:

may have said:

I enjoy horsemounting because it's fun, easy, fast, natural (to me).

Otherwise it's clomp, clomp, straddle, step & go -- mechanical and without grace. 'jus my opinion.

Mileages vary.

For me, the right leg goes over the top onto the pedal (which has been brought to the 1 o'lock
position beforehand) and then the takeoff proceeds as the left foot leaves the ground.
(Conventional pedals, no clips or cleats.)

I've done a horse-mount sometimes, but I just prefer the other way. Everyone finds the way that
work for them.

---------------

I might do the same but the 3-3/4" gain on the left pedal stepup allows for easier clearance on the
seat legover with my short legs.

Fellow rider of the true clipless; i.e., pedals without clips.

Bruce Ball

On 25 Jan 2004 11:48:40 -0800, [email hidden] (Carl Fogel)
wrote:

---------- clip

Quoted message said:

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

---------- clip

Pardon for butting in, but I wondered the same and pondered for a time, suspecting the left upper
spokes might increase in tension.

However, a simple ping test reveals the right driveside upper spokes increase in tension. Simply
lean the bike to the right, apply force to the left pedal, pluck the spokes, note the rise in
pitch/frequency.

Bruce Ball

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

Quoted message said:

On 25 Jan 2004 11:48:40 -0800, [email hidden] (Carl Fogel) wrote:

---------- clip

Quoted message said:

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

---------- clip

Pardon for butting in, but I wondered the same and pondered for a time, suspecting the left upper
spokes might increase in tension.

However, a simple ping test reveals the right driveside upper spokes increase in tension. Simply
lean the bike to the right, apply force to the left pedal, pluck the spokes, note the rise in
pitch/frequency.

Bruce Ball

Dear Bruce,

You're not butting in at all. I'm delighted to hear anyone, particularly when they're kind enough
not to say that I had it backwards.

I just looked over my babbling and strongly suspect that I had it completely backwards.

With the wheel leaning over to the right, some or all left-side spokes should lose tension, while
some or all right spokes should gain tension.

Or so I think now that you've politely pointed out yet another of my imbecilities. I appreciate it.
(Poor Jobst may well be grinding his teeth and wondering what he ever did to deserve such bizarre
questions carefully asked backward.)

Thanks,

Carl Fogel

Quoted message said:

Please explain how this can have any effect considering that I can coast down a road standing on
one pedal while leaning as far out to one side as I like with no spoke failures. Noting that spoke
failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a foreign
object snagged a spoke....

And so the correlation between the soap content of Ivory [TM] and the failure mode of spokes
is made. 😉

Tom Sherman - Quad Cities

Carl Fogel said:

Quoted message said:

[as a cause for broken spokes]

Quoted message said:

Quoted message said:

Quoted message said:

1) Do not mount a bicycle like a horse, by putting a foot in the left pedal and swinging the
right leg over the seat to the other pedal.

Quoted message said:

Quoted message said:

Please explain how this can have any effect considering that I can coast down a road standing on
one pedal while leaning as far out to one side as I like with no spoke failures. Noting that
spoke failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a
foreign object snagged a spoke, what effect does mounting the bicycle have on the endurance of
spokes?

Quoted message said:

Quoted message said:

This is one of the most bizarre claims I have heard about the spoked bicycle wheel. Having never
heard it before, I wonder what sort of underground passes along such myth and lore.

Quoted message said:

I expect that you're right, but now I want to know what actually happens to the spokes when a
rider stands on one pedal and leans way over while coasting straight down the road.

I think you'll find that in "the Bicycle Wheel" with a diagram of tension shift from one side to the
other. From cosine error, the characteristics are not entirely symmetrical although for small
displacements, the instantaneous lateral compliance is the same.

Quoted message said:

As the pre-tensioned left and right side spokes pass under the axle, they lose tension, right?

Quoted message said:

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

Quoted message said:

I looked at "The Bicycle Wheel," where you go over lateral stiffness and later showed your testing
rig for demonstrating that tying and soldering are merely decorative, but I'm not sure how to
apply what you wrote.

Look at the lateral stiffness diagram and observe the curves of spoke tension and lateral force for
a given displacement.

Quoted message said:

I think that the left side spokes should gain tension with the wheel leaning over to the right,
but do they all gain tension equally?

This is a section view considering one typical spoke from each side. Depending on the cross section
of the rim, this gets distributed over more than just one opposing pair.

Quoted message said:

Or does the force act only through the rim just above the contact patch? Either way, does this
gain in tension cancel out the loss of tension on the left side spokes rolling under the axle?

Quoted message said:

Similarly, do all the right-side spokes lose tension because the wheel is leaning to the right, or
just the ones on the bottom? And could the bottom ones get into trouble because the loss in
tension from the sideways leaning is added to the loss in tension from the normal load?

I think you are pulling my leg, so to speak. Look at the other displacement curves to get a feel for
load distribution. Wheel collapse diagrams also give a hint to what is occurring.

Quoted message said:

Here's a crude view from the rear of what I'm wondering about: top rim do all left-side / / spokes
gain tension / / due to lean --> / / <--do all right-side spokes or just a few / / lose tension
due to lean? lower left-side / / or just a few lower right-side spokes? spokes? left hub right / /
can left-side / / tension gain / / cancel normal / / <--can right-side tension loss lowermost-
spoke / / plus normal lowermost-spoke tension loss tension loss? / / get out of hand? rim -------------
ground and contact patch

The spoked wheel is not a rigid disk as you picture it. Its lateral deflections are similar to its
radial deflections, local to the point of loading. Even if it were a rigid disk, you picture shows
that at least at the horizontal diameter, there would be no change, but that model is unreal anyway.

Quoted message said:

I suspect that even with a heavy rider the sideways load is much less than the vertical load, but
I'm still curious about what the leaning does to the spoke tension--do all spokes on one side
change tension equally, or just the ones down near the contact patch?

Side loads are insignificant in nearly all riding. That is why 10-speed clusters, and their far
narrower flange spacing that tradition, work.

The subject comes up often from track riders who believe that there are enormous side loads while
speeding around the banking of a track as they visualize their entire weight is pressing only down
while the wheels are contacting the "wall".

Jobst Brandt [email hidden]

Bill Ball said:

Quoted message said:

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

Quoted message said:

Pardon for butting in, but I wondered the same and pondered for a time, suspecting the left upper
spokes might increase in tension.

Quoted message said:

However, a simple ping test reveals the right driveside upper spokes increase in tension. Simply
lean the bike to the right, apply force to the left pedal, pluck the spokes, note the rise in
pitch/frequency.

I think you can find that experiment in "the Bicycle Wheel" where wheel collapse from a lateral load
at the ground is described. I still have the wheels that was used to verify that theoretical
analysis of why a wheel forms a "taco" when it is overloaded laterally at one location.

Jobst Brandt [email hidden]

Carl Fogel said:

Quoted message said:

[as a cause for broken spokes]

Quoted message said:

Quoted message said:

Quoted message said:

1) Do not mount a bicycle like a horse, by putting a foot in the left pedal and swinging the
right leg over the seat to the other pedal.

Quoted message said:

Quoted message said:

Please explain how this can have any effect considering that I can coast down a road standing on
one pedal while leaning as far out to one side as I like with no spoke failures. Noting that
spoke failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a
foreign object snagged a spoke, what effect does mounting the bicycle have on the endurance of
spokes?

Quoted message said:

Quoted message said:

This is one of the most bizarre claims I have heard about the spoked bicycle wheel. Having never
heard it before, I wonder what sort of underground passes along such myth and lore.

Quoted message said:

I expect that you're right, but now I want to know what actually happens to the spokes when a
rider stands on one pedal and leans way over while coasting straight down the road.

Quoted message said:

As the pre-tensioned left and right side spokes pass under the axle, they lose tension, right?

You can review this in the diagrams for lateral loading in "the Bicycle Wheel" where lateral force
and stiffness is shown for a cross section of the wheel at the load point.

Quoted message said:

But if I'm standing on the left pedal with the bike and wheel leaning way over to the right, what
does that do to the spokes?

Quoted message said:

I looked at "The Bicycle Wheel," where you go over lateral stiffness and later showed your testing
rig for demonstrating that tying and soldering are merely decorative, but I'm not sure how to
apply what you wrote.

I don't see how tying and soldering got into this but what you read is correct, it has no effect on
wheel strength.

Quoted message said:

I think that the left side spokes should gain tension with the wheel leaning over to the right,
but do they all gain tension equally? Or does the force act only through the rim just above the
contact patch? Either way, does this gain in tension cancel out the loss of tension on the left
side spokes rolling under the axle?

Quoted message said:

Similarly, do all the right-side spokes lose tension because the wheel is leaning to the right, or
just the ones on the bottom? And could the bottom ones get into trouble because the loss in
tension from the sideways leaning is added to the loss in tension from the normal load?

Look at the diagram showing wheel collapse with a side load applied at one point on the wheel. All
the diagrams are of naturally loaded wheels as they would be used so the load is applied at the
ground contact point.

Quoted message said:

Here's a crude view from the rear of what I'm wondering about: top rim do all left-side / / spokes
gain tension / / due to lean --> / / <--do all right-side spokes or just a few / / lose tension
due to lean? lower left-side / / or just a few lower right-side spokes? spokes? left hub right / /
can left-side / / tension gain / / cancel normal / / <--can right-side tension loss lowermost-
spoke / / plus normal lowermost-spoke tension loss tension loss? / / get out of hand? rim -------------
ground and contact patch

Wheels are not rigid disks and do not respond to side loads as your diagram suggests. Besides, the
wheel collapse diagram shows that the rim deflects to the same side on top as at the ground contact
patch. That is how the "taco" or saddle failure occurs. I still have the wheel that was made into a
taco to verify the theoretical explanation of side load failure.

Quoted message said:

I suspect that even with a heavy rider the sideways load is much less than the vertical load, but
I'm still curious about what the leaning does to the spoke tension--do all spokes on one side
change tension equally, or just the ones down near the contact patch?

Review the relevant parts of the book. It's all there.

Jobst Brandt [email hidden]

On Mon, 26 Jan 2004 20:44:42 -0600, Tom Sherman

may have said:

Quoted message said:

Please explain how this can have any effect considering that I can coast down a road standing on
one pedal while leaning as far out to one side as I like with no spoke failures. Noting that
spoke failures are 99.44% fatigue failures if they didn't occur at the first loading or a when a
foreign object snagged a spoke....

And so the correlation between the soap content of Ivory [TM] and the failure mode of spokes
is made. 😉

It's really an amazing coincidence, innit?

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.