For Mr Chisholm

[Sandy]

While the site is in French, many of the articles are in English.
Translating the title, it's "Handbuilt wheels".

I hope you may find something interesting there.
--
Sandy
Verneuil-sur-Seine
*******

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

 

[dvt]

Sandy wrote:
> While the site is in French, many of the articles are in English.
> Translating the title, it's "Handbuilt wheels".
>
> I hope you may find something interesting there.

What site?

--
Dave
dvt at psu dot edu

 

[[email protected]]

http://lyricsplayground.com/alpha/songs/p/poormrchisholm.shtml

 

[Johnny Sunset]

[email protected] wrote:
> http://lyricsplayground.com/alpha/songs/p/poormrchisholm.shtml

Now we know why Peter Chisholm uses a tensiometer instead of listening
to the pitch of plucked spokes!

--
Tom Sherman - Fox River Valley

 

[Sandy]

Dans le message de
news:[email protected],
Qui si parla Campagnolo <[email protected]> a réfléchi, et puis a déclaré :
> Lou Holtman wrote:

>> That is what you always say, and I agree with that. BUT at a certain
>> moment all these things (fitness, bikefit etc. etc.) are given facts
>> and a 20 Watt difference in RR is 20 Watt and for most mortals this
>> is significant compared to the total power they can put into the
>> cranks. Is this important? For non racers probably not, but it is
>> significant.
>
> BUT as I also say all the time, that 20watt difference is NOT
> predictable or consistent and from day to day, as long as a PERSON
> propels the bicycle, should not be counted on. Besides I really doubt
> that the difference is 20watts, more than a 10% increase or more for
> most of us.

I have to ask - what do you object to ? To the report and its methodology ?
To a quantification of measured differences ? I'll bet you pick tires for
your own personal use based on a bunch of criteria, but if one felt really
sluggish and another felt relatively faster, don't you think the differences
are real ? On the other hand, there are lots of guys who ride whatever was
at the lowest selling price when they needed tires. Could that be your
criterion ? I just can't understand why tested values are objectionable.

The other point, about the PERSON being a part of the mix. Absolutely true.
But if you ride 100 km a day, and do that for the life of a tire, say 50
times, don't you figure that this person gets the benefit of his average
form over that period ? So, if on the average, he benefits from a better
rolling resistance with one tire, isn't that a good tire to buy, instead of
one where his average form gives him slower, less rewarding results ?
--
Sandy

The above is guaranteed 100% free of sarcasm,
denigration, snotty remarks, indifference, platitudes, fuming demands that
"you do the math", conceited visions of a better world on wheels according
to [insert NAME here].

 

[Qui si parla Campagnolo]

Sandy wrote:
> Dans le message de
> news:[email protected],
> Qui si parla Campagnolo <[email protected]> a réfléchi, et puis a déclaré :
> > Lou Holtman wrote:
>
> >> That is what you always say, and I agree with that. BUT at a certain
> >> moment all these things (fitness, bikefit etc. etc.) are given facts
> >> and a 20 Watt difference in RR is 20 Watt and for most mortals this
> >> is significant compared to the total power they can put into the
> >> cranks. Is this important? For non racers probably not, but it is
> >> significant.
> >
> > BUT as I also say all the time, that 20watt difference is NOT
> > predictable or consistent and from day to day, as long as a PERSON
> > propels the bicycle, should not be counted on. Besides I really doubt
> > that the difference is 20watts, more than a 10% increase or more for
> > most of us.
>
> I have to ask - what do you object to ? To the report and its methodology ?
> To a quantification of measured differences ? I'll bet you pick tires for
> your own personal use based on a bunch of criteria, but if one felt really
> sluggish and another felt relatively faster, don't you think the differences
> are real ? On the other hand, there are lots of guys who ride whatever was
> at the lowest selling price when they needed tires. Could that be your
> criterion ? I just can't understand why tested values are objectionable.

Tested values are so sterile when taken from a machione, w/o the
relatively unknown of a person's performance from day to day...which
varies a lot. Too much buying based on numbers taken in isolation, and
then applied to performance as if it's etched in stone For example, get
this wheel and you save 2 seconds per kilo, type thing. My gain some
speed, may not..depends on so much of a person's output day to day
which varies hugely.

I think most bike stuff should be chosen for it's reliability, not how
to 'buy' speed. If something breaks, the speed goes down a lot.

>
> The other point, about the PERSON being a part of the mix. Absolutely true.
> But if you ride 100 km a day, and do that for the life of a tire, say 50
> times, don't you figure that this person gets the benefit of his average
> form over that period ? So, if on the average, he benefits from a better
> rolling resistance with one tire, isn't that a good tire to buy, instead of
> one where his average form gives him slower, less rewarding results ?

May get a reward, may not.
> --
> Sandy
>
> The above is guaranteed 100% free of sarcasm,
> denigration, snotty remarks, indifference, platitudes, fuming demands that
> "you do the math", conceited visions of a better world on wheels according
> to [insert NAME here].

 

[[email protected]]

Sandy wrote:
> I have to ask - what do you object to ? To the report and its methodology ?

Here's what I have a problem with: there is not quantification of the
way the glue is applied or which glue is used. It's pretty clear from
Brandt's ancient tests that the glue layer and type of glue have a
significant impact on rolling resistance, where the use of track
shellac brought tubular rolling resistance down to that of clinchers.
What is still unknown is to what degree minimizing the thickness of the
glue layer and maximizing the strength of the glue bond will improve
rolling resistance. Any test that compares clinchers and tubulars
without examining the glue variable is hard to draw conclusions from.

Furthermore, there has been some conjecture that the type of road
surface affects the rolling resistance of a tire, and that tires that
perform best on a flawless surface like the test drum pictured in that
test may not perform the best on a surface that is more real-life.

As an aside, I don't agree with their use of a five-axis chart. I don't
think that tire width belongs on it. It should be a manipulated
variable that affects the other four. The others are factors of tire
performance, tire width is not- it only *affects* tire performance.

I think that 20 watts per tire (can't tell whether their measurements
are for a pair or a single tire) is significant and I would consider
switching to clinchers if it's for real, but I really don't know what
to make of rolling resistance tests that are based on a perfectly
smooth surface like this.

 

[Adrien]

I wrote the study for the quality of the torque transfer from the hub
to the spoke. Actually at the begginning I just wanted to find the
equation to know how tangential to the hub the spoke is.

But still, your comment is true, the spoke isn't tangential to the rim
but the nipple always go in a position to transmit the most torque to
be the least stressed as possible (natural element position) so we can
stand that it's as the spoke was tangential to the rim.

Your definition of the tension is right but then I think the best way
to transmit a rotational force, a torque is to be tangential. If the
force has to be transmit by a radial part, it will bends, it's physical
it can't be differently. From this, you can tell that radial is the
worst case to transmit torque so torque transfer quality is 0% while a
tangential spoke would transmit it with the least deformation, with the
least 'non-adapted' strain.
I don't agree with you when you say that it doesn't stand.

Then, you say that "the other half is associated with decrease in
tension", well it means that they don't work while the torque is
transmit as accelerating since the nipple will try to quit its bed so
you agree with me when I stand that "one spoke in two transmits torque"
and that the pushing spokes only act while braking".

I read Jobst Brandt's and Gerd Schraner's books, I found them really
informative even if they sometimes don't think the same thing.

I mailed Damon Rinard and a mechanical enginner about my article a few
days before publishing it. Both told me that it was ok to publish it
because it was interesting and mistake less.
But hey, I never said that they're god and all what they say is right!

Nice to speak with you and hear differents opinions Tom Ace.

Adrien.
www.rouesartisaales.com

 

[Ted Bennett]

"Adrien" <[email protected]> wrote:

> I wrote the study for the quality of the torque transfer from the hub
> to the spoke. Actually at the begginning I just wanted to find the
> equation to know how tangential to the hub the spoke is.
>
> But still, your comment is true, the spoke isn't tangential to the rim
> but the nipple always go in a position to transmit the most torque to
> be the least stressed as possible (natural element position) so we can
> stand that it's as the spoke was tangential to the rim.
>
> Your definition of the tension is right but then I think the best way
> to transmit a rotational force, a torque is to be tangential.

Correct.

> If the
> force has to be transmit by a radial part, it will bends, it's physical
> it can't be differently.

That's where you are wrong. In a prestressed structure such as a
bicycle wheel, all the forces are transmitted by the spokes, which are
always in tension. There are no compressive forces along the spokes.

> From this, you can tell that radial is the
> worst case to transmit torque so torque transfer quality is 0% while a
> tangential spoke would transmit it with the least deformation, with the
> least 'non-adapted' strain.
> I don't agree with you when you say that it doesn't stand.
>
> Then, you say that "the other half is associated with decrease in
> tension", well it means that they don't work while the torque is
> transmit as accelerating since the nipple will try to quit its bed so
> you agree with me when I stand that "one spoke in two transmits torque"
> and that the pushing spokes only act while braking".

This is distressing to hear from someone who has written an article
about wheels. It shows an important lack of understanding of the
physics of spoked wheels. A force can be transmitted by reduction in
tension just as by an increase in tension. The nipple will not "quit
its bed" unless the tension is reduced to zero, and that will never
happen with driving torque produced by pedaling.

The torque is transmitted by all the spokes, not just the "pulling"
spokes.

> I read Jobst Brandt's and Gerd Schraner's books, I found them really
> informative even if they sometimes don't think the same thing.
>
> I mailed Damon Rinard and a mechanical enginner about my article a few
> days before publishing it. Both told me that it was ok to publish it
> because it was interesting and mistake less.
> But hey, I never said that they're god and all what they say is right!
>
> Nice to speak with you and hear differents opinions Tom Ace.
>
> Adrien.
> www.rouesartisaales.com

--
Ted Bennett

 

[Adrien]

>> If the
>> force has to be transmit by a radial part, it will bends, it's physical
>> it can't be differently.
>That's where you are wrong. In a prestressed structure such as a
>bicycle wheel, all the forces are transmitted by the spokes, which are
>always in tension. There are no compressive forces along the spokes.

Well, I never said that there are compressives forces along the spokes.
I don't understand what you mean so.

>This is distressing to hear from someone who has written an article
>about wheels. It shows an important lack of understanding of the
>physics of spoked wheels. A force can be transmitted by reduction in
>tension just as by an increase in tension. The nipple will not "quit
>its bed" unless the tension is reduced to zero, and that will never
>happen with driving torque produced by pedaling.
>
>The torque is transmitted by all the spokes, not just the "pulling"
>spokes.

I'm sorry to disappoint you, I really though it worked this way.
I don't understand how the force can be transmitted by a tension
reduction. Could you explain it better? If the pushing spokes transmit
the force, how do they do? they have nothing to push. Don't tell me
that they will push the tubular
No joke, I really don't get it.

Thanks.
Adrien.

 

[[email protected]]

Adrien Gontier writes:

>>> If the force has to be transmit by a radial part, it will bends,
>>> it's physical it can't be differently.

>> That's where you are wrong. In a prestressed structure such as a
>> bicycle wheel, all the forces are transmitted by the spokes, which
>> are always in tension. There are no compressive forces along the
>> spokes.

> Well, I never said that there are compressive forces along the
> spokes. I don't understand what you mean so.

>> This is distressing to hear from someone who has written an article
>> about wheels. It shows an important lack of understanding of the
>> physics of spoked wheels. A force can be transmitted by reduction
>> in tension just as by an increase in tension. The nipple will not
>> "quit its bed" unless the tension is reduced to zero, and that will
>> never happen with driving torque produced by pedaling.

>> The torque is transmitted by all the spokes, not just the "pulling"
>> spokes.

> I'm sorry to disappoint you, I really though it worked this way. I
> don't understand how the force can be transmitted by a tension
> reduction. Could you explain it better? If the pushing spokes
> transmit the force, how do they do? they have nothing to push.
> Don't tell me that they will push the tubular No joke, I really
> don't get it.

You say you read "the Bicycle Wheel" but what you say is contrary to
the explanations and computations that demonstrate how torque is
transmitted. I think you should review what was explained in words
and graphically about "pulling" and "pushing" spokes. This is the
basic problem why bicycle wheels have been around for more than 100
years with no scientific explanation of how they support loads on
wires.

Every year one or more people come to this forum and discover what has
been incorrectly believed about wire spoked wheels, most of them form
GB or Europe. They do this after having seen or read a bit in "the
Bicycle Wheel" which they seem to ignore because it conflicts with
their beliefs.

Pedaling torque is not one of the major loads in a reasonably built
bicycle wheel as you can see in the book. If nothing else, I suggest
you look at the stress diagrams of loaded wheels.

Jobst Brandt

 

[Ted Bennett]

"Adrien" <[email protected]> wrote:

> >> If the
> >> force has to be transmit by a radial part, it will bends, it's physical
> >> it can't be differently.
> >That's where you are wrong. In a prestressed structure such as a
> >bicycle wheel, all the forces are transmitted by the spokes, which are
> >always in tension. There are no compressive forces along the spokes.
>
> Well, I never said that there are compressives forces along the spokes.
> I don't understand what you mean so.

Perhaps I misunderstood what you said about the impossibility of radial
forces, due to the spoke bending.

> >This is distressing to hear from someone who has written an article
> >about wheels. It shows an important lack of understanding of the
> >physics of spoked wheels. A force can be transmitted by reduction in
> >tension just as by an increase in tension. The nipple will not "quit
> >its bed" unless the tension is reduced to zero, and that will never
> >happen with driving torque produced by pedaling.
> >
> >The torque is transmitted by all the spokes, not just the "pulling"
> >spokes.
>
> I'm sorry to disappoint you, I really though it worked this way.
> I don't understand how the force can be transmitted by a tension
> reduction. Could you explain it better? If the pushing spokes transmit
> the force, how do they do? they have nothing to push. Don't tell me
> that they will push the tubular
> No joke, I really don't get it.

This will probably restart another flame war, but here goes:

Consider an unloaded wheel at rest. The spokes all are in equal tension.
Now if a bicycle is attached to the hub, then the spokes must supply a
vertical force to the hub. Measurement of individual spoke tension will
demonstrate that the upward force is provided almost entirely by a
reduction in tension of several spokes below the hub, rather than an
increase of tension of the spokes above the hub. This is the "pushing"
to which I was referring. Of course a spoke cannot "push" directly, but
a reduction in tension certainly changes the force that that the hub
experiences.

In the case of a driven hub applying torque via spokes to the rim, half
the spokes apply the torque by a reduction of tension, and the other
half by a tension increase.

Your article, I think, is not very useful to the prospective buyer
because it is misleading. Although wheel weights and rim deflection are
always of interest, the article only covers boutique wheels, which are
not lighter than wheels which can be repaired with standard parts, are
significantly less expensive, and can be ridden with a damaged spoke.
Those boutique wheels sometimes have aerodynamic advantages, but that
benefits only elite racers and not the huge majority of cyclists. The
drawbacks tend to make cycling less accessible because of high cost,
presenting wheels as an irreducible component which must be replaced as
a unit rather than repaired.

--
Ted Bennett

 

[Luns Tee]

In article <[email protected]>,
Adrien <[email protected]> wrote:
>I wrote the study for the quality of the torque transfer from the hub
>to the spoke. Actually at the begginning I just wanted to find the
>equation to know how tangential to the hub the spoke is.

.....

>Your definition of the tension is right but then I think the best way
>to transmit a rotational force, a torque is to be tangential. If the
>force has to be transmit by a radial part, it will bends, it's physical
>it can't be differently.

There is no bending. A radial component to the force does not
infer bending - the vector sum of the tangential and radial components
of the force applied to the hub still lie on the line of the spoke -
this does not bend the spoke.

Consider a tangentially spoked wheel. Now replace each spoke
with a somewhat shorter one, and some sort of extension to go from the
spoke elbow to the hub, say something like a twisted loop of wire, or
a link of a chain. This changes practically nothing about the long
section of spoke aside from its length.

Now replace the hub and all the extensions with a hub with an
equivalent larger flange diameter. This also changes nothing for the
spokes.

>From this, you can tell that radial is the
>worst case to transmit torque so torque transfer quality is 0% while a
>tangential spoke would transmit it with the least deformation, with the
>least 'non-adapted' strain.

The 0 to 100% figure of merit you refer to isn't a particularly
meaningful one, but does relate to a valid concept. The more meaningful
figure of merit would be diameter of the tangent circle: the magnitude
of spoke tension changes relative to torque relates directly to this.

The percentage measure you give amounts to this diameter
normalized to the actual spoke hole diameter, and obscures what happens
as you change flange diameters.

-Luns

 

[jim beam]

[email protected] wrote:
> Adrien Gontier writes:
>
>
>>>>If the force has to be transmit by a radial part, it will bends,
>>>>it's physical it can't be differently.
>
>
>>>That's where you are wrong. In a prestressed structure such as a
>>>bicycle wheel, all the forces are transmitted by the spokes, which
>>>are always in tension. There are no compressive forces along the
>>>spokes.
>
>
>>Well, I never said that there are compressive forces along the
>>spokes. I don't understand what you mean so.
>
>
>>>This is distressing to hear from someone who has written an article
>>>about wheels. It shows an important lack of understanding of the
>>>physics of spoked wheels. A force can be transmitted by reduction
>>>in tension just as by an increase in tension. The nipple will not
>>>"quit its bed" unless the tension is reduced to zero, and that will
>>>never happen with driving torque produced by pedaling.
>
>
>>>The torque is transmitted by all the spokes, not just the "pulling"
>>>spokes.
>
>
>>I'm sorry to disappoint you, I really though it worked this way. I
>>don't understand how the force can be transmitted by a tension
>>reduction. Could you explain it better? If the pushing spokes
>>transmit the force, how do they do? they have nothing to push.
>>Don't tell me that they will push the tubular No joke, I really
>>don't get it.
>
>
> You say you read "the Bicycle Wheel" but what you say is contrary to
> the explanations and computations that demonstrate how torque is
> transmitted. I think you should review what was explained in words
> and graphically about "pulling" and "pushing" spokes. This is the
> basic problem why bicycle wheels have been around for more than 100
> years with no scientific explanation of how they support loads on
> wires.
>
> Every year one or more people come to this forum and discover what has
> been incorrectly believed about wire spoked wheels, most of them form
> GB or Europe. They do this after having seen or read a bit in "the
> Bicycle Wheel" which they seem to ignore because it conflicts with
> their beliefs.

hmmm, is geography also responsible for fundamental mistakes
like not knowing the difference between strain aging material and
non-strain aging material? how about their confusing residual stress
for loading distortion?

>
> Pedaling torque is not one of the major loads in a reasonably built
> bicycle wheel as you can see in the book. If nothing else, I suggest
> you look at the stress diagrams of loaded wheels.
>
> Jobst Brandt

 

[Ron Ruff]

Matt O'Toole wrote:
>
> If someone has it, maybe they could post RR data from recent tire tests by
> Tour and Le Cycle. I've seen bits and pieces of this data here and there,
> posted on various web forums that I don't read regularly. I saw one chart
> for the top 10 or so best performers, which included both tubular and
> clincher models. IIRC the very best was a clincher though.
>

The chart that was posted above *is* the Tour test data from 10/2005.

> So how much does it really matter anyway?
>

Quite a bit... if you are racing, or just concerned about going fast.
The percentage difference in speed is about the same for climbing as
riding on the flat. For instance, the Pro2 is 3.4% faster than a
GP3000, and on a hill this would also be true... if you could go 10mph
with the GP3000s, then you'd be able to go ~10.34mph with the Pro2s.

In my opinion, that is a big difference for tires that are both
intended for high performance use.

Tire Crr Speed* Delta

Deda Tre Giro d'Italia 0.0038 23.08
Vittoria Open Corsa Evo CX 0.0039 23.05 0.03
Michelin Pro 2 Race 0.0042 22.96 0.12
Vittoria Diamante Pro Rain 0.0044 22.90 0.18
Michelin Megamium 2 0.0047 22.81 0.27
Pariba Revolution 0.0048 22.78 0.30
Michelin Carbon 0.0050 22.72 0.36
Panaracer Stradius Pro 0.0051 22.69 0.39
Schwalbe Stelvio Plus 0.0052 22.66 0.42
Schwalbe Stelvio Evolution Front 0.0056 22.54 0.54
Continental GP Force (rear) 0.0057 22.51 0.57
Hutchinson Fusion 0.0057 22.51 0.57
Schwalbe Stelvio Evolution Rear 0.0057 22.51 0.57
Continental Ultra GatorSkin 0.0058 22.48 0.60
Ritchey Pro Race Slick WCS 0.0058 22.48 0.60
Schwalbe Stelvio 0.0059 22.45 0.63
Specialized S-Works Mondo 0.0061 22.39 0.69
Continental GP 3000 0.0067 22.21 0.87
Hutchinson Top Speed 0.0069 22.15 0.93
Continental GP Attack (front) 0.0073 22.04 1.04

*
in MPH
185lb rider + bike
250W rider output
CdA = .32m^2 (racing crouch, normal road bike)
Transmission efficiency = 96%

 

[Michael Press]

In article
<[email protected]>,
"Ron Ruff" <[email protected]> wrote:

> Matt O'Toole wrote:
> >
> > If someone has it, maybe they could post RR data from recent tire tests by
> > Tour and Le Cycle. I've seen bits and pieces of this data here and there,
> > posted on various web forums that I don't read regularly. I saw one chart
> > for the top 10 or so best performers, which included both tubular and
> > clincher models. IIRC the very best was a clincher though.
> >
>
> The chart that was posted above *is* the Tour test data from 10/2005.
>
> > So how much does it really matter anyway?
> >
>
> Quite a bit... if you are racing, or just concerned about going fast.
> The percentage difference in speed is about the same for climbing as
> riding on the flat. For instance, the Pro2 is 3.4% faster than a
> GP3000, and on a hill this would also be true... if you could go 10mph
> with the GP3000s, then you'd be able to go ~10.34mph with the Pro2s.
>
> In my opinion, that is a big difference for tires that are both
> intended for high performance use.
>
> Tire Crr Speed* Delta
>
> Deda Tre Giro d'Italia 0.0038 23.08
> Vittoria Open Corsa Evo CX 0.0039 23.05 0.03
> Michelin Pro 2 Race 0.0042 22.96 0.12
> Vittoria Diamante Pro Rain 0.0044 22.90 0.18
> Michelin Megamium 2 0.0047 22.81 0.27
> Pariba Revolution 0.0048 22.78 0.30
> Michelin Carbon 0.0050 22.72 0.36
> Panaracer Stradius Pro 0.0051 22.69 0.39
> Schwalbe Stelvio Plus 0.0052 22.66 0.42
> Schwalbe Stelvio Evolution Front 0.0056 22.54 0.54
> Continental GP Force (rear) 0.0057 22.51 0.57
> Hutchinson Fusion 0.0057 22.51 0.57
> Schwalbe Stelvio Evolution Rear 0.0057 22.51 0.57
> Continental Ultra GatorSkin 0.0058 22.48 0.60
> Ritchey Pro Race Slick WCS 0.0058 22.48 0.60
> Schwalbe Stelvio 0.0059 22.45 0.63
> Specialized S-Works Mondo 0.0061 22.39 0.69
> Continental GP 3000 0.0067 22.21 0.87
> Hutchinson Top Speed 0.0069 22.15 0.93
> Continental GP Attack (front) 0.0073 22.04 1.04
>
> *
> in MPH
> 185lb rider + bike
> 250W rider output
> CdA = .32m^2 (racing crouch, normal road bike)
> Transmission efficiency = 96%

Too bad they did not publish data for Avocet Fastrack.

--
Michael Press

 

[Sorni]

Ron Ruff wrote:

> Tire Crr Speed* Delta

Delta?

 

[Ron Ruff]

Sorni wrote:
> Delta?

Speed compared to the best tire.

 

[Sorni]

Ron Ruff wrote:
> Sorni wrote:

>> Delta?

> Speed compared to the best tire.

Merci.