Why build your own wheel?

[Ted]

Trevor Jeffrey wrote:

> Ted wrote in message ...
> >Trevor Jeffrey wrote:
> >If your wheels are adequately supported "in all service conditions",
> >then why do you feel the need for linseed oil to prevent spokes from
> >vibrating loose, as you put it? I have inspected and worked on many
> >wheels, and I have never seen a spoke vibrate loose, unless its tension
> >was low enough to fall to zero in use.
>
> That should of course read all normal service conditions. You have assumed
> that the tension fell to 0. Vibration will undo any nut if the shock is
> great enough. The bolt or spoke does not have to be loose for the nut or
> nipple to move. The tension does not have to fall to zero for a nipple to
> unwind.
>
> Without some form of positive retention the nipples will unwind with the
> build method I advocate.
>
> Trevor

Then it would seem that your method results in spokes that are too loose.

I don't think a wheel that rattles loose simply from use is an adequate
wheel. I also simply don't see the downside of increased tension, as
long as the rim isn't tacoed or otherwise damaged.

 

[Trevor Jeffrey]

Ted wrote in message ...
>
>Then it would seem that your method results in spokes that are too loose.
>
Adequate tension to maintain lateral stability at maximum load. Not loose.

>I don't think a wheel that rattles loose simply from use is an adequate
>wheel. I also simply don't see the downside of increased tension, as
>long as the rim isn't tacoed or otherwise damaged.

I'm not suggesting my wheels rattle loose, they do not, the nipples are
oiled with linseed.
It is the excessive tension in the spokes which buckles the wheel.
Why can you not recognise the symptom for what it is? Buckled. Is the use
of the word tacoed specific to the Jobstian wonderland or has it crept out
anywhere else?

Trevor

 

[Trevor Jeffrey]

Robert wrote in message ...
>Just about all of it. My view is that you are going to all ends of the
>earth to try to save millimetres of territory. For what purpose? Do you
>never concede to a good argument from an opponent, or do you believe
>that everyone who's gone up against you in this thread is just plain wrong?

The argument is invalid. Absolute strain levels have been withheld.

Trevor

 

[daveornee]

<SNIP>

Without some form of positive retention the nipples will unwind with the
build method I advocate.

Trevor[/QUOTE]

Now, I am sure that I don't want to follow "the build method".

Nipples on the wheels I build don't unwind. I have ridden over 10,000 miles of loaded touring on one set of wheels I built without having to turn one nipple even 1/4 turn. The tension was identical from day 1 to the day I rechecked them... after over 10,000 miles. The force required to rotate the nipple isn't sufficient to overcome the friction in the threads + nipple to rim hole interfaces. I also experienced no broken spokes or changes in wheel true during this time. So unless your definition of "positive retention" is the friction in a wheel built following Jobst book, I am done reading what you write... unless I am in the mood for a good laugh.

 

[Trevor Jeffrey]

daveornee wrote in message ...
>
><SNIP>
>
>Without some form of positive retention the nipples will unwind with
>the
>build method I advocate.
>
>Trevor
>
>Now, I am sure that I don't want to follow "the build method".
>
>Nipples on the wheels I build don't unwind. I have ridden over 10,000
>miles of loaded touring on one set of wheels I built without having to
>turn one nipple even 1/4 turn. The tension was identical from day 1 to
>the day I rechecked them... after over 10,000 miles. The force required
>to rotate the nipple isn't sufficient to overcome the friction in the
>threads + nipple to rim hole interfaces. I also experienced no broken
>spokes or changes in wheel true during this time. So unless your
>definition of "positive retention" is the friction in a wheel built
>following Jobst book, I am done reading what you write... unless I am in
>the mood for a good laugh.

So you have an unnatural aversion to use standard engineering practice in
bicycle wheel wheelbuillding and are willing to risk a wheel with poor
overload capacity resulting in buckling and any personal injury thereby
caused.

It's your life, do what you will.

Trevor

 

[Ted]

Trevor Jeffrey wrote:

> Ted wrote in message ...
> >
> >Then it would seem that your method results in spokes that are too loose.
> >
> Adequate tension to maintain lateral stability at maximum load. Not loose.
>
> >I don't think a wheel that rattles loose simply from use is an adequate
> >wheel. I also simply don't see the downside of increased tension, as
> >long as the rim isn't tacoed or otherwise damaged.
>
> I'm not suggesting my wheels rattle loose, they do not, the nipples are
> oiled with linseed.
> It is the excessive tension in the spokes which buckles the wheel.
> Why can you not recognise the symptom for what it is? Buckled. Is the use
> of the word tacoed specific to the Jobstian wonderland or has it crept out
> anywhere else?
>
> Trevor

Alright, m'lad, buckled it is. To use the word "tacoed" as a descriptor
is a reference to the characteristic shape of the little dish. It's
obvious to anyone who lives places where Mexican food is available, but
I would be open to arguments that the humble taco is as much American as
Mexican.

With regards to wheel tension, what is the downside to higher tension
than what you propose, as long as the rim isn't buckled or otherwise
damaged?

 

[Weisse Luft]

The Taco is native American. Mexico is a country on the North American Continent.

 

[Ted]

Weisse Luft wrote:

> The Taco is native American. Mexico is a country on the North American
> Continent.


Yes. So is Canada. I hesitate when I use "American" to mean "resident
of the USA" but to most Earthlings the terms are synonymous.

What would be a better term? USAian seems a little awkward. . .

 

[Trevor Jeffrey]

Ted wrote in message ...
>
>With regards to wheel tension, what is the downside to higher tension
>than what you propose, as long as the rim isn't buckled or otherwise
>damaged?

That it would be of greater risk of buckling. The rim can only withstand a
certain magnitude of compressive force without lateral restraint before
buckling is attained through a minor lateral force. This is the same for
all beams in compression. Tensioning the spokes is correct, but only to the
usable amount. there is no requirement to go over and above that which will
support the maximum load attained. It depends on use what values of maximum
attainable force should be used. Shock loads lasting for a hundredth of a
second should be ignored because the wheel recovers before loss of control.
As the spokes are progressively tensioned, the rim sustains greater
compression, eventually it will give.

Trevor

 

[Tim McNamara]

Trevor Jeffrey wrote:
> Ted wrote in message ...
>
>>Trevor Jeffrey wrote:
>>If your wheels are adequately supported "in all service conditions",
>>then why do you feel the need for linseed oil to prevent spokes from
>>vibrating loose, as you put it? I have inspected and worked on many
>>wheels, and I have never seen a spoke vibrate loose, unless its tension
>>was low enough to fall to zero in use.
>
> That should of course read all normal service conditions. You have assumed
> that the tension fell to 0. Vibration will undo any nut if the shock is
> great enough. The bolt or spoke does not have to be loose for the nut or
> nipple to move. The tension does not have to fall to zero for a nipple to
> unwind.

What force is unscrewing the nipple, and how does it overcome friction
between the nipple and the spoke and the nipple and the rim? How does
the nipple vibrate if it is restrained by contact with the rim and spoke?

> Without some form of positive retention the nipples will unwind with the
> build method I advocate.

Which is why it's not a good methhod of building wheels.

 

[Trevor Jeffrey]

Tim McNamara wrote in message
<[email protected]>...
>
>What force is unscrewing the nipple, and how does it overcome friction
>between the nipple and the spoke and the nipple and the rim? How does
>the nipple vibrate if it is restrained by contact with the rim and spoke?

Vibration along with the outthrusting force of the rim. A clutch plate for
a small car uses 5x 8mm bolts torqued to 50lbf.ft this is high, and yet
those five bolts still require threadlock.

>> Without some form of positive retention the nipples will unwind with the
>> build method I advocate.
>
>Which is why it's not a good methhod of building wheels.

The fact that the nipple, which is not a fastener but an adjustment for
spoke length, require restraint does not make a particular wheel build
inferior. It is only ignorance and bad practice which make for poor method.

Trevor

 

[Sheldon Brown]

Trevor Jeffrey queried:

> Is the use of the word tacoed specific to the Jobstian wonderland or has it crept out
> anywhere else?

It's not particularly Jobstian, but it is a west-coast terminology.

We Yanks in the east are more likely to use the term "potato chipped."
though "tacoed" is gaining ground even east of the Mississippi, due to
the cultural hegemony of California-speak.

I don't like the term "tacoed", much as I like tacos. It seems that a
more appropriate term would be "tortillaed" but that's a battle I don't
feel like fighting. I'm saving my energies for the never-ending battle
against "crank arm" and "brake arch."

The French use the term "voilée" which is derived from the word "voile",
which, in its feminine form, means a sail, also a highly apposite image.

Sheldon "Cyclexicographer" Brown
+-----------------------------------------+
| Man invented language to satisfy his |
| deep need to complain. -- Lily Tomlin |
+-----------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[dianne_1234]

On Wed, 18 Aug 2004 19:48:12 GMT, Ted <[email protected]>
wrote:

>With regards to wheel tension, what is the downside to higher tension
>than what you propose, as long as the rim isn't buckled or otherwise
>damaged?

Spoke tension does have its limits.

From my experience, thin wall rims suffer earlier fatigue failures
when spoke tension is higher, some hubs suffer earlier flange
failures, and it can be more difficult to turn the spoke nipples
(especially on the road with minimal tools).

There may be others.

 

[Mr_Potatohead]

Higher tension I suppose increases the "R" ratio, i.e. the ratio of minimum to maximum stress in the spoke and therefore increases fatigue life. I've never had a problem with spoke breakage personally. However, higher spoke tension puts more localized bending stress around the spoke hole in the rim which is where and why rim cracks start and propagate.

Ted wrote in message ...
>
>With regards to wheel tension, what is the downside to higher tension
>than what you propose, as long as the rim isn't buckled or otherwise
>damaged?

That it would be of greater risk of buckling. The rim can only withstand a
certain magnitude of compressive force without lateral restraint before
buckling is attained through a minor lateral force. This is the same for
all beams in compression. Tensioning the spokes is correct, but only to the
usable amount. there is no requirement to go over and above that which will
support the maximum load attained. It depends on use what values of maximum
attainable force should be used. Shock loads lasting for a hundredth of a
second should be ignored because the wheel recovers before loss of control.
As the spokes are progressively tensioned, the rim sustains greater
compression, eventually it will give.

Trevor

 

[Trevor Jeffrey]

Mr_Potatohead wrote in message ...
>
>Higher tension I suppose increases the "R" ratio, i.e. the ratio of
>minimum to maximum stress in the spoke and therefore increases fatigue
>life. I've never had a problem with spoke breakage personally. However,
>higher spoke tension puts more localized bending stress around the spoke
>hole in the rim which is where and why rim cracks start and propagate.
>

Are you really attempting to delude yourself? The variation in tension is
important to fatigue life. Any bending stress in important to fatigue
life. Cracking around the spoke hole in the rim is very localised and of
surface nature only, unless extreme and unnecessary tension exists within
the spokes.

Trevor

 

[Trevor Jeffrey]

dianne_1234 wrote in message ...
>
>Spoke tension does have its limits.
>
>From my experience, thin wall rims suffer earlier fatigue failures
>when spoke tension is higher, some hubs suffer earlier flange
>failures, and it can be more difficult to turn the spoke nipples
>(especially on the road with minimal tools).

Please elaborate upon fatigue failure of rims.

Trevor

 

[Martin]

I am contemplating changing my Campy double (39/53) to a
triple using a Campy Racing-T (30/40/50) that I have on
hand. I have the crank, fd, bb and a 28 chaining.

Can I use my 39 and 53 with the 28 or 30 on the triple or
will shifting suffer with the Ergo shifters because of a
lack of pins/ramps?

Be well.

Martin

 

[Trevor Jeffrey]

Sheldon Brown wrote in message <[email protected]>...
Trevor Jeffrey queried:

> Is the use of the word tacoed specific to the Jobstian wonderland or has
it crept out
> anywhere else?

It's not particularly Jobstian, but it is a west-coast terminology.

We Yanks in the east are more likely to use the term "potato chipped."
though "tacoed" is gaining ground even east of the Mississippi, due to
the cultural hegemony of California-speak.

I don't like the term "tacoed", much as I like tacos. It seems that a
more appropriate term would be "tortillaed" but that's a battle I don't
feel like fighting. I'm saving my energies for the never-ending battle
against "crank arm" and "brake arch."

The French use the term "voilée" which is derived from the word "voile",
which, in its feminine form, means a sail, also a highly apposite image.

Spanish but also Mexican. Listen you guys, stop drinking Mescal, it stinks,
drink Tequila, the good stuff is like a reasonable Scotch malt.

Is it a brake arm or a calliper arm, or just that bit connected to the pivot
and the brake shoe/pad. ( Inconsequential in Jobstian wonderland).

Trevor

oops, lost quoty bits. guess, its not important. its inconsequential.
?

 

[Trevor Jeffrey]

daveornee wrote in message ...
>
><SNIP>
>
>Without some form of positive retention the nipples will unwind with
>the
>build method I advocate.
>
>Trevor
>
>Now, I am sure that I don't want to follow "the build method".
>
>Nipples on the wheels I build don't unwind. I have ridden over 10,000
>miles of loaded touring on one set of wheels I built without having to
>turn one nipple even 1/4 turn. The tension was identical from day 1 to
>the day I rechecked them... after over 10,000 miles. The force required
>to rotate the nipple isn't sufficient to overcome the friction in the
>threads + nipple to rim hole interfaces. I also experienced no broken
>spokes or changes in wheel true during this time. So unless your
>definition of "positive retention" is the friction in a wheel built
>following Jobst book, I am done reading what you write... unless I am in
>the mood for a good laugh.
>
After reading your 3months of postings, I am quite surprised by your
reaction. Between yourself and Jim Beam, you manage to cover the exact same
method which I advocate, only you will not reduce spoke tension.

Trevor

 

[Trevor Jeffrey]

Mr_Potatohead wrote in message ...
>
>Higher tension I suppose increases the "R" ratio, i.e. the ratio of
>minimum to maximum stress in the spoke and therefore increases fatigue
>life. I've never had a problem with spoke breakage personally. However,
>higher spoke tension puts more localized bending stress around the spoke
>hole in the rim which is where and why rim cracks start and propagate.
>

From A A Wells "The meaning of fitness for purpose and the concept of
defect Tolerance"

Wells defines fitness for purpose as that design
which is consciously chosen to be the right level of material and
fabrication quality for each application, having regard to the risks and
consequences of failure; it may be contrasted with the best quality that can
be achieved within a given set of circumstances, which may be inadequate for
some exacting requirements, and needlessly uneconomic for others which are
less demanding. A characteristic of the fitness-for-purpose approach is
that it requires to be defined beforehand according to known facts, and by
agreement with purchasers which will subsequently seek to be national and
eventually international.



Fracture mechanics, risk analysis and reliability, non-destructive
examination, and quality assurance as well as electron microscope and
spectrograph analyses should be used to asses fitness for purpose.

The ratio of stress levels is not relevant to fatigue. The variation of
stress is important. Most failures are due to bending stress at the hub
juncture. The forming of the distinct bend at the crossing so as to enable
the spoke to take its load variation on straight sections reduces the
bending moments at the hub juncture to a minimum.

I have seen surface rim cracks around spoke holes, this being due to deep
layer anodisation unable to stretch with the deformation of the substrate.
It gave partial cause for concern when first seen. The failure of the wheel
due to buckling demonstrated other problems more serious than fatigue
failure, which were directly contributed to inordinately high magnitudes of
spoke tension.

Trevor



Trevor