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Main
Date: 30 Aug 2007 05:47:36
From: D'ohBoy
Subject: Opinions on Spoke Breakage Scenario
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All of a sudden, two spokes have broken in two weeks. Here are the
details:
- Broken spokes were Radial-spoked CX-Ray NDS Rear
- 32 hole OCR rim/Record Hub
- Spoke tension is very even - I use a tensiometer
- Breakage is at the bend
- 2000 or so miles on the set, problem-free prior
I just don't get why this is happening. Bad spokes? I saw it
suggested elsewhere that a under-spec spoke hole (diameter) in the hub
could cause this as well. DS is around 95 kgf. NDS is whatever it
took to dish it properly (didn't do the conversion, just made sure
they were evenly tensioned).
Thanks for your input,
D'ohBoy
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Date: 03 Sep 2007 07:13:20
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
Front rim braked wheels don't have the
> torque issue at the spoke/hub interface.
>
>
> --
> daveornee
Ummmm, duud. You're telling me that when the brakes grab the rim and
apply a torque (braking of the rim) that the spokes ONLY experience
forces at the rim?!!
Wow, we live in a very different physical world.
The hub is the connection between the spokes and the frame (and
biker). Any torque on the rim WILL be experienced by the hub flanges
as well. The frame, hub and cyclist have a forward force, which is
transferred through the hub and resisted via the opposite radial force
of the brake. The hub/spoke area is a 'flexible' interface where
force can manifest as windup, etc...
Please explain to me how I am wrong, without unsupported assertions
like "Front rim braked wheels don't have the torque issue at the spoke/
hub interface."
D'ohBoy
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| | |
Date: 03 Sep 2007 17:09:43
From:
Subject: Re: Opinions on Spoke Breakage Scenario
|
someone writes:
>> Front rim braked wheels don't have the torque issue at the
>> spoke/hub interface.
> Ummmm, duud. You're telling me that when the brakes grab the rim and
> apply a torque (braking of the rim) that the spokes ONLY experience
> forces at the rim?!!
> Wow, we live in a very different physical world.
> The hub is the connection between the spokes and the frame (and
> biker). Any torque on the rim WILL be experienced by the hub
> flanges as well. The frame, hub and cyclist have a forward force,
> which is transferred through the hub and resisted via the opposite
> radial force of the brake. The hub/spoke area is a 'flexible'
> interface where force can manifest as windup, etc...
> Please explain to me how I am wrong, without unsupported assertions
> like "Front rim braked wheels don't have the torque issue at the
> spoke/ hub interface."
I think you aren't following what was written. There is no torque
transmitted to the hub using rim brakes. In contrast the only way the
hub to which the (disk or drum) brake is attached can get its torque
to the tire is through the spokes, similar to the way rear hubs
transmit sprocket torque to the tire.
Let's not confuse torque with linear brake forces. Torque from a hub
brake is rotational while brake forces from rim brakes are linear and
cause a retarding linear force on the axle. The relation of these
forces are shown in displacement diagrams in "the Bicycle Wheel".
Jobst Brandt
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| | |
Date: 04 Sep 2007 01:35:23
From: daveornee
Subject: Re: Opinions on Spoke Breakage Scenario
|
D'ohBoy Wrote:
> Front rim braked wheels don't have the
> > torque issue at the spoke/hub interface.
> >
> >
> > --
> > daveornee
>
> Ummmm, duud. You're telling me that when the brakes grab the rim and
> apply a torque (braking of the rim) that the spokes ONLY experience
> forces at the rim?!!
>
> Wow, we live in a very different physical world.
>
> The hub is the connection between the spokes and the frame (and
> biker). Any torque on the rim WILL be experienced by the hub flanges
> as well. The frame, hub and cyclist have a forward force, which is
> transferred through the hub and resisted via the opposite radial force
> of the brake. The hub/spoke area is a 'flexible' interface where
> force can manifest as windup, etc...
>
> Please explain to me how I am wrong, without unsupported assertions
> like "Front rim braked wheels don't have the torque issue at th
> spoke/
> hub interface."
>
> D'ohBoy
I was trying to help you understand the source of spoke breakage in th
rear wheel with Non-Drive side radial spokes. You asserted that a ri
braked front wheel would have much larger torque values than would b
experienced in the spokes of your rear wheel non-drive side spokes.
The only restraining torque forces on the front hub is bearing frictio
and seal drag. I assert that these restraining forces are much smalle
than the torque applied by pedaling forces and transferred to th
non-drive side of the hub.
It seems you forgot to look at the portions of my responses that ar
intended to help you address your original rear wheel spoke breakag
problem.
Instead of couching my thoughts in questions, I will come out an sa
that my opinion of the Jobst method of "stress relief" by squeezin
pairs of spokes is either not useful or possibly detrimental.
Barnette's method (A.K.A. Mavic method) of stabilization is better.
Radial spoking has many negative potential issues. Nipple unwind
spoke fatique, hub flange fatigue, etc. are all issues.
I am satisfied to "live in a very different physical world" than you.
Did you look at my question of plastic deformation in the directions o
squezes of the radial spokes potentially caused by the Jobst method?
What mechanism(s) were involved in reducing the spoke tension
--
daveornee
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Date: 03 Sep 2007 12:25:07
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
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re: post 31-how long and to what advantage?
were the bends inspected for cracks using magnification?
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Date: 03 Sep 2007 05:01:18
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
daveornee wrote:
> How do you stress relieve "Jobst-style" with nearly flat spokes in a
> radial pattern?
Thick leather work gloves work for me. Grab adjacent spokes and
squeeze.
> CX-Ray spokes are very tough and have been fatigue tested as the
> "longest lasting" of all Sapim spoke models. CX-Ray spokes are
> flattened Laser spokes.
That's why I bought them. And they are actually a different SS alloy
than their standard Lasers, IIRC.
> I suspect that the CX-Ray spokes were not up to typical Sapim standards
> and/or they suffered some damage.
I am veering away from this as a source of my issue. I don't know
how, but I do know that the tension in my rear wheel dropped a huge
amount.
> I am not a fan of radial spoking in bicycle wheels, especially in the
> rear wheel.
> The slightest bit of torque transfer to the left rear flange would
> quicken the fatigue of both the hub flange and the spokes.
Meh. So, have you any real-life experience with this as an issue? I
have heard the stories and seen the few pictures, but I have yet to
come to truly believe that this is a problem with a higher spoke count
and a well-tensioned wheel.
I would accept that there are long-term issues with hub flange
fatigue, but one would think that all those radially-spoked fronts
would be exploding as their riders brake heavily down mountain roads.
I would imagine heavy braking at 50 mph puts more torque on a front
wheel's spokes than I could ever put into the NDS of my rear wheel.
Not to fire up the radial-spoking wars or anything, JMO (and a small
amount of personal experience).
D'ohBoy
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| | |
Date: 03 Sep 2007 23:45:29
From: daveornee
Subject: Re: Opinions on Spoke Breakage Scenario
|
D'ohBoy Wrote:
> daveornee wrote:
>
> > How do you stress relieve "Jobst-style" with nearly flat spokes in a
> > radial pattern?
>
> Thick leather work gloves work for me. Grab adjacent spokes and
> squeeze.
>
> > CX-Ray spokes are very tough and have been fatigue tested as the
> > "longest lasting" of all Sapim spoke models. CX-Ray spokes are
> > flattened Laser spokes.
>
> That's why I bought them. And they are actually a different SS alloy
> than their standard Lasers, IIRC.
>
> > I suspect that the CX-Ray spokes were not up to typical Sapi
> standards
> > and/or they suffered some damage.
>
> I am veering away from this as a source of my issue. I don't know
> how, but I do know that the tension in my rear wheel dropped a huge
> amount.
>
> > I am not a fan of radial spoking in bicycle wheels, especially i
> the
> > rear wheel.
> > The slightest bit of torque transfer to the left rear flange would
> > quicken the fatigue of both the hub flange and the spokes.
>
> Meh. So, have you any real-life experience with this as an issue? I
> have heard the stories and seen the few pictures, but I have yet to
> come to truly believe that this is a problem with a higher spoke count
> and a well-tensioned wheel.
>
> I would accept that there are long-term issues with hub flange
> fatigue, but one would think that all those radially-spoked fronts
> would be exploding as their riders brake heavily down mountain roads.
> I would imagine heavy braking at 50 mph puts more torque on a front
> wheel's spokes than I could ever put into the NDS of my rear wheel.
>
> Not to fire up the radial-spoking wars or anything, JMO (and a small
> amount of personal experience).
>
> D'ohBoy
OK on the lether glove squeezing method. Is it possible that yo
squeezed the spokes sufficiently that you plastically deformed th
spokes in the directions of the squeeze(s)?
Inox 18/8 alloy used in Laser and CX-Ray. Sapim tells me that th
additional fatique life of the CX-Ray comes from the additional col
working processes applied to the material.
Since I don't build rear wheels with radial spokes my persona
experience is limited to wheels that where built that way by others..
and brought to me for repair. Front rim braked wheels don't have th
torque issue at the spoke/hub interface
--
daveornee
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| | | |
Date: 03 Sep 2007 15:01:35
From: Michael Press
Subject: Re: Opinions on Spoke Breakage Scenario
|
In article
<daveornee.2wc7pn@no-mx.forums.cyclingforums.com >,
daveornee
<daveornee.2wc7pn@no-mx.forums.cyclingforums.com >
wrote:
> D'ohBoy Wrote:
> > daveornee wrote:
> >
> > > How do you stress relieve "Jobst-style" with nearly flat spokes in a
> > > radial pattern?
> >
> > Thick leather work gloves work for me. Grab adjacent spokes and
> > squeeze.
> >
> > > CX-Ray spokes are very tough and have been fatigue tested as the
> > > "longest lasting" of all Sapim spoke models. CX-Ray spokes are
> > > flattened Laser spokes.
> >
> > That's why I bought them. And they are actually a different SS alloy
> > than their standard Lasers, IIRC.
> >
> > > I suspect that the CX-Ray spokes were not up to typical Sapim
> > standards
> > > and/or they suffered some damage.
> >
> > I am veering away from this as a source of my issue. I don't know
> > how, but I do know that the tension in my rear wheel dropped a huge
> > amount.
> >
> > > I am not a fan of radial spoking in bicycle wheels, especially in
> > the
> > > rear wheel.
> > > The slightest bit of torque transfer to the left rear flange would
> > > quicken the fatigue of both the hub flange and the spokes.
> >
> > Meh. So, have you any real-life experience with this as an issue? I
> > have heard the stories and seen the few pictures, but I have yet to
> > come to truly believe that this is a problem with a higher spoke count
> > and a well-tensioned wheel.
> >
> > I would accept that there are long-term issues with hub flange
> > fatigue, but one would think that all those radially-spoked fronts
> > would be exploding as their riders brake heavily down mountain roads.
> > I would imagine heavy braking at 50 mph puts more torque on a front
> > wheel's spokes than I could ever put into the NDS of my rear wheel.
> >
> > Not to fire up the radial-spoking wars or anything, JMO (and a small
> > amount of personal experience).
> >
> > D'ohBoy
> OK on the lether glove squeezing method. Is it possible that you
> squeezed the spokes sufficiently that you plastically deformed the
> spokes in the directions of the squeeze(s)?
> Inox 18/8 alloy used in Laser and CX-Ray. Sapim tells me that the
> additional fatique life of the CX-Ray comes from the additional cold
> working processes applied to the material.
> Since I don't build rear wheels with radial spokes my personal
> experience is limited to wheels that where built that way by others...
> and brought to me for repair. Front rim braked wheels don't have the
> torque issue at the spoke/hub interface.
Fatigue failure in a spoke elbow starts when it is
formed at the factory. Cold forming the elbow leaves in
residual stress. Spokes in a wheel in service undergo
unloading and loading every time they pass the contact
patch. This means that the elbow undergoes cyclic small
changes in stress and strain. If portions of the elbow
are already at their elastic limit, then those portions
will fatigue. The theory and practice of stress relief,
confirmed in miles of riding, is to put one great
honking stress on the spokes of the tensioned wheel,
taking the high stress areas of the spoke elbow past
the elastic limit into plastic deformation. Now the
cyclic stress on the spokes of a ridden wheel do not
take the spoke elbows near the elastic limit, and put
the fatigue limit in the astronomical range: +100000
mile. Another prophylactic is to bend the spokes after
lacing and before tensioning to give a fair lead from
flange to rim.
--
Michael Press
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| | | | |
Date: 03 Sep 2007 15:18:36
From: jim beam
Subject: Re: Opinions on Spoke Breakage Scenario
|
Michael Press wrote:
> In article
> <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>,
> daveornee
> <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>
> wrote:
>
>> D'ohBoy Wrote:
>>> daveornee wrote:
>>>
>>>> How do you stress relieve "Jobst-style" with nearly flat spokes in a
>>>> radial pattern?
>>> Thick leather work gloves work for me. Grab adjacent spokes and
>>> squeeze.
>>>
>>>> CX-Ray spokes are very tough and have been fatigue tested as the
>>>> "longest lasting" of all Sapim spoke models. CX-Ray spokes are
>>>> flattened Laser spokes.
>>> That's why I bought them. And they are actually a different SS alloy
>>> than their standard Lasers, IIRC.
>>>
>>>> I suspect that the CX-Ray spokes were not up to typical Sapim
>>> standards
>>>> and/or they suffered some damage.
>>> I am veering away from this as a source of my issue. I don't know
>>> how, but I do know that the tension in my rear wheel dropped a huge
>>> amount.
>>>
>>>> I am not a fan of radial spoking in bicycle wheels, especially in
>>> the
>>>> rear wheel.
>>>> The slightest bit of torque transfer to the left rear flange would
>>>> quicken the fatigue of both the hub flange and the spokes.
>>> Meh. So, have you any real-life experience with this as an issue? I
>>> have heard the stories and seen the few pictures, but I have yet to
>>> come to truly believe that this is a problem with a higher spoke count
>>> and a well-tensioned wheel.
>>>
>>> I would accept that there are long-term issues with hub flange
>>> fatigue, but one would think that all those radially-spoked fronts
>>> would be exploding as their riders brake heavily down mountain roads.
>>> I would imagine heavy braking at 50 mph puts more torque on a front
>>> wheel's spokes than I could ever put into the NDS of my rear wheel.
>>>
>>> Not to fire up the radial-spoking wars or anything, JMO (and a small
>>> amount of personal experience).
>>>
>>> D'ohBoy
>> OK on the lether glove squeezing method. Is it possible that you
>> squeezed the spokes sufficiently that you plastically deformed the
>> spokes in the directions of the squeeze(s)?
>> Inox 18/8 alloy used in Laser and CX-Ray. Sapim tells me that the
>> additional fatique life of the CX-Ray comes from the additional cold
>> working processes applied to the material.
>> Since I don't build rear wheels with radial spokes my personal
>> experience is limited to wheels that where built that way by others...
>> and brought to me for repair. Front rim braked wheels don't have the
>> torque issue at the spoke/hub interface.
>
> Fatigue failure in a spoke elbow starts when it is
> formed at the factory. Cold forming the elbow leaves in
> residual stress.
no, that's jobstian myth cause by insufficient understanding and
insufficient observation. residual stress at the fatigue initiation
points is essentially zero or even compressive. fatigue /is/ however
observed to initiate at surface defects and the spoke elbow /is/ subject
to bending.
> Spokes in a wheel in service undergo
> unloading and loading every time they pass the contact
> patch. This means that the elbow undergoes cyclic small
> changes in stress and strain. If portions of the elbow
> are already at their elastic limit,
untrue. if this were the case, fatigue lives would be close to zero.
> then those portions
> will fatigue. The theory and practice of stress relief,
> confirmed in miles of riding, is to put one great
> honking stress on the spokes of the tensioned wheel,
> taking the high stress areas of the spoke elbow past
> the elastic limit into plastic deformation.
ever heard of miner's cumulative damage rule? apparently neither you
nor jobst have.
> Now the
> cyclic stress on the spokes of a ridden wheel do not
> take the spoke elbows near the elastic limit, and put
> the fatigue limit in the astronomical range: +100000
> mile. Another prophylactic is to bend the spokes after
> lacing and before tensioning to give a fair lead from
> flange to rim.
see above.
all the while let's just ignore the /real/ reason for fatigue
mitigation, that of improved materials. oh well, nothing like ignorance
and stubbornness to liven up a sunny afternoon.
|
| | | | | |
Date: 03 Sep 2007 16:30:07
From: Michael Press
Subject: Re: Opinions on Spoke Breakage Scenario
|
In article
<-aOdna3Q3L2jFUHbnZ2dnUVZ_tCrnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Michael Press wrote:
> > In article
> > <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>,
> > daveornee
> > <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>
> > wrote:
> >
> >> D'ohBoy Wrote:
> >>> daveornee wrote:
> >>>
> >>>> How do you stress relieve "Jobst-style" with nearly flat spokes in a
> >>>> radial pattern?
> >>> Thick leather work gloves work for me. Grab adjacent spokes and
> >>> squeeze.
> >>>
> >>>> CX-Ray spokes are very tough and have been fatigue tested as the
> >>>> "longest lasting" of all Sapim spoke models. CX-Ray spokes are
> >>>> flattened Laser spokes.
> >>> That's why I bought them. And they are actually a different SS alloy
> >>> than their standard Lasers, IIRC.
> >>>
> >>>> I suspect that the CX-Ray spokes were not up to typical Sapim
> >>> standards
> >>>> and/or they suffered some damage.
> >>> I am veering away from this as a source of my issue. I don't know
> >>> how, but I do know that the tension in my rear wheel dropped a huge
> >>> amount.
> >>>
> >>>> I am not a fan of radial spoking in bicycle wheels, especially in
> >>> the
> >>>> rear wheel.
> >>>> The slightest bit of torque transfer to the left rear flange would
> >>>> quicken the fatigue of both the hub flange and the spokes.
> >>> Meh. So, have you any real-life experience with this as an issue? I
> >>> have heard the stories and seen the few pictures, but I have yet to
> >>> come to truly believe that this is a problem with a higher spoke count
> >>> and a well-tensioned wheel.
> >>>
> >>> I would accept that there are long-term issues with hub flange
> >>> fatigue, but one would think that all those radially-spoked fronts
> >>> would be exploding as their riders brake heavily down mountain roads.
> >>> I would imagine heavy braking at 50 mph puts more torque on a front
> >>> wheel's spokes than I could ever put into the NDS of my rear wheel.
> >>>
> >>> Not to fire up the radial-spoking wars or anything, JMO (and a small
> >>> amount of personal experience).
> >>>
> >>> D'ohBoy
> >> OK on the lether glove squeezing method. Is it possible that you
> >> squeezed the spokes sufficiently that you plastically deformed the
> >> spokes in the directions of the squeeze(s)?
> >> Inox 18/8 alloy used in Laser and CX-Ray. Sapim tells me that the
> >> additional fatique life of the CX-Ray comes from the additional cold
> >> working processes applied to the material.
> >> Since I don't build rear wheels with radial spokes my personal
> >> experience is limited to wheels that where built that way by others...
> >> and brought to me for repair. Front rim braked wheels don't have the
> >> torque issue at the spoke/hub interface.
> >
> > Fatigue failure in a spoke elbow starts when it is
> > formed at the factory. Cold forming the elbow leaves in
> > residual stress.
>
> no, that's jobstian myth cause by insufficient understanding and
> insufficient observation. residual stress at the fatigue initiation
> points is essentially zero or even compressive. fatigue /is/ however
> observed to initiate at surface defects and the spoke elbow /is/ subject
> to bending.
>
> > Spokes in a wheel in service undergo
> > unloading and loading every time they pass the contact
> > patch. This means that the elbow undergoes cyclic small
> > changes in stress and strain. If portions of the elbow
> > are already at their elastic limit,
>
> untrue. if this were the case, fatigue lives would be close to zero.
>
>
> > then those portions
> > will fatigue. The theory and practice of stress relief,
> > confirmed in miles of riding, is to put one great
> > honking stress on the spokes of the tensioned wheel,
> > taking the high stress areas of the spoke elbow past
> > the elastic limit into plastic deformation.
>
> ever heard of miner's cumulative damage rule? apparently neither you
> nor jobst have.
>
>
> > Now the
> > cyclic stress on the spokes of a ridden wheel do not
> > take the spoke elbows near the elastic limit, and put
> > the fatigue limit in the astronomical range: +100000
> > mile. Another prophylactic is to bend the spokes after
> > lacing and before tensioning to give a fair lead from
> > flange to rim.
>
> see above.
>
> all the while let's just ignore the /real/ reason for fatigue
> mitigation, that of improved materials. oh well, nothing like ignorance
> and stubbornness to liven up a sunny afternoon.
You are wrong and do not mind being offensively wrong,
because nobody knows who you are. Well, get this,
Sunny Jim, nobody knows who you are.
Here is your white feather.
_____
/~ / ~\
/' \ , ~/'
|
| | | | | | |
Date: 03 Sep 2007 16:49:45
From: jim beam
Subject: Re: Opinions on Spoke Breakage Scenario
|
Michael Press wrote:
> In article
> <-aOdna3Q3L2jFUHbnZ2dnUVZ_tCrnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Michael Press wrote:
>>> In article
>>> <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>,
>>> daveornee
>>> <daveornee.2wc7pn@no-mx.forums.cyclingforums.com>
>>> wrote:
>>>
>>>> D'ohBoy Wrote:
>>>>> daveornee wrote:
>>>>>
>>>>>> How do you stress relieve "Jobst-style" with nearly flat spokes in a
>>>>>> radial pattern?
>>>>> Thick leather work gloves work for me. Grab adjacent spokes and
>>>>> squeeze.
>>>>>
>>>>>> CX-Ray spokes are very tough and have been fatigue tested as the
>>>>>> "longest lasting" of all Sapim spoke models. CX-Ray spokes are
>>>>>> flattened Laser spokes.
>>>>> That's why I bought them. And they are actually a different SS alloy
>>>>> than their standard Lasers, IIRC.
>>>>>
>>>>>> I suspect that the CX-Ray spokes were not up to typical Sapim
>>>>> standards
>>>>>> and/or they suffered some damage.
>>>>> I am veering away from this as a source of my issue. I don't know
>>>>> how, but I do know that the tension in my rear wheel dropped a huge
>>>>> amount.
>>>>>
>>>>>> I am not a fan of radial spoking in bicycle wheels, especially in
>>>>> the
>>>>>> rear wheel.
>>>>>> The slightest bit of torque transfer to the left rear flange would
>>>>>> quicken the fatigue of both the hub flange and the spokes.
>>>>> Meh. So, have you any real-life experience with this as an issue? I
>>>>> have heard the stories and seen the few pictures, but I have yet to
>>>>> come to truly believe that this is a problem with a higher spoke count
>>>>> and a well-tensioned wheel.
>>>>>
>>>>> I would accept that there are long-term issues with hub flange
>>>>> fatigue, but one would think that all those radially-spoked fronts
>>>>> would be exploding as their riders brake heavily down mountain roads.
>>>>> I would imagine heavy braking at 50 mph puts more torque on a front
>>>>> wheel's spokes than I could ever put into the NDS of my rear wheel.
>>>>>
>>>>> Not to fire up the radial-spoking wars or anything, JMO (and a small
>>>>> amount of personal experience).
>>>>>
>>>>> D'ohBoy
>>>> OK on the lether glove squeezing method. Is it possible that you
>>>> squeezed the spokes sufficiently that you plastically deformed the
>>>> spokes in the directions of the squeeze(s)?
>>>> Inox 18/8 alloy used in Laser and CX-Ray. Sapim tells me that the
>>>> additional fatique life of the CX-Ray comes from the additional cold
>>>> working processes applied to the material.
>>>> Since I don't build rear wheels with radial spokes my personal
>>>> experience is limited to wheels that where built that way by others...
>>>> and brought to me for repair. Front rim braked wheels don't have the
>>>> torque issue at the spoke/hub interface.
>>> Fatigue failure in a spoke elbow starts when it is
>>> formed at the factory. Cold forming the elbow leaves in
>>> residual stress.
>> no, that's jobstian myth cause by insufficient understanding and
>> insufficient observation. residual stress at the fatigue initiation
>> points is essentially zero or even compressive. fatigue /is/ however
>> observed to initiate at surface defects and the spoke elbow /is/ subject
>> to bending.
>>
>>> Spokes in a wheel in service undergo
>>> unloading and loading every time they pass the contact
>>> patch. This means that the elbow undergoes cyclic small
>>> changes in stress and strain. If portions of the elbow
>>> are already at their elastic limit,
>> untrue. if this were the case, fatigue lives would be close to zero.
>>
>>
>>> then those portions
>>> will fatigue. The theory and practice of stress relief,
>>> confirmed in miles of riding, is to put one great
>>> honking stress on the spokes of the tensioned wheel,
>>> taking the high stress areas of the spoke elbow past
>>> the elastic limit into plastic deformation.
>> ever heard of miner's cumulative damage rule? apparently neither you
>> nor jobst have.
>>
>>
>>> Now the
>>> cyclic stress on the spokes of a ridden wheel do not
>>> take the spoke elbows near the elastic limit, and put
>>> the fatigue limit in the astronomical range: +100000
>>> mile. Another prophylactic is to bend the spokes after
>>> lacing and before tensioning to give a fair lead from
>>> flange to rim.
>> see above.
>>
>> all the while let's just ignore the /real/ reason for fatigue
>> mitigation, that of improved materials. oh well, nothing like ignorance
>> and stubbornness to liven up a sunny afternoon.
>
> You are wrong
really? wrong like claiming a material without an endurance limit can
be made fatigue proof "wrong", or you can't think for yourself so you
regurgitate other peoples mistakes "wrong"?
> and do not mind being offensively wrong,
yeah, i call bullshitters for what they are.
> because nobody knows who you are. Well, get this,
> Sunny Jim, nobody knows who you are.
>
> Here is your white feather.
>
> _____
> /~ / ~\
> /' \ , ~/'
>
|
| |
Date: 02 Sep 2007 14:08:34
From: datakoll
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
cool! what does the riding experience (not the wheel building
experience) gain from going to a rim distortion level then back to non-
distortion? over a qualitiative "this is tight enough"?
what's the trueing time difference between leaving the spoke torques
at "this is tight enough" compared to time spent going to a "less than
distortion quantitative torque level"?
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Date: 01 Sep 2007 16:30:56
From: D'ohBoy
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
datakoll wrote:
> if you contemplate a humor vandal counting off spokes in a parking
> lot....
> where do you wrok? google-boeing-state u physics?
Ummmm... kinda sorta.... high level physics IS involved....
D'ohBoy
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Date: 01 Sep 2007 20:42:13
From: datakoll
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
if you contemplate a humor vandal counting off spokes in a parking
lot....
where do you wrok? google-boeing-state u physics?
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Date: 01 Sep 2007 13:23:06
From: D'ohBoy
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
Nate Knutson wrote:
> > Weird. Wonder if the spoke eyelets were not fully "seated"? And the
> > stresses of riding the wheel caused them to seat in?
>
> It seems inconceivable for anything like that to happen in a way where
> the tension was reduced so evenly on each and every spoke that the
> wheel didn't go out of true. Was the dish of the wheel affected?
>
> Same tensionmeter, being used the same way? Didn't accidentally use
> the wrong column in the chart at some point?
Same tensiometer, same methodology. Each spoke gets three
measurements during each assessment. In addition to the use of the
tensiometer, I have had great success with JB's method of tensioning
the rim to distortion and then backing off a small amount. The
distortion method gets me to the 'correct' tension, and the
tensiometer assures even tension. Sorry, Jim Beam, but it works for
me. I did the same thing this time too, which resulted in a tension
of 110 kgf DS/70 kgf NDS.
It does seem inconceivable, doesn't it? As an aside, it is
interesting to note that the total tension on the front and rear
wheels via just backing off the distortion point was ~3000 kgf for
both the front and rear wheels = > 2*90*16 = 2880 for the front and
110*16+70*16 = 2880 for the rear.
A paranoiac might start to think they (Bushco, of course) were out to
get me. Strand me on the road, then pick me off out in the boonies,
Easy Rider style. Oh, they have access to the bike too. When I go to
group rides after work my bike is in my car all day in the work
parking lot. Hmmmmm........
Huh. Well, I'm going to do some short rides with the wheels while my
wife is at home, carry my cell and see how they do.
And Peter C., no, I am not going to put 14/15's on the NDS! Maybe
round 14/17's, but these are supposed to be my light wheels and that
would add (GASP!) 48 gms (SHUDDER!) to the set ;-D. Besides, I
already have a set of 36 hole CXP-33's built with 14/15 all the way
round; I don't need another set of training wheels.
D'ohBoy
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Date: 01 Sep 2007 10:37:13
From: Nate Knutson
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
> Weird. Wonder if the spoke eyelets were not fully "seated"? And the
> stresses of riding the wheel caused them to seat in?
It seems inconceivable for anything like that to happen in a way where
the tension was reduced so evenly on each and every spoke that the
wheel didn't go out of true. Was the dish of the wheel affected?
Same tensionmeter, being used the same way? Didn't accidentally use
the wrong column in the chart at some point?
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Date: 03 Sep 2007 06:42:43
From: jim beam
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
Nate Knutson wrote:
>> Weird. Wonder if the spoke eyelets were not fully "seated"? And the
>> stresses of riding the wheel caused them to seat in?
>
> It seems inconceivable for anything like that to happen in a way where
> the tension was reduced so evenly on each and every spoke that the
> wheel didn't go out of true. Was the dish of the wheel affected?
>
> Same tensionmeter, being used the same way? Didn't accidentally use
> the wrong column in the chart at some point?
>
that's where i'd put my money.
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Date: 01 Sep 2007 10:31:44
From: Qui si parla Campagnolo-www.vecchios.com
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
On Sep 1, 9:04 am, D'ohBoy <peteng...@yahoo.com > wrote:
> Weird.
>
> Coupla things - in an earlier post I said that I could only get the
> tension up to about 95 kgf before the rim started to distort. That
> applied not to the rear but rather the front. I had gotten the rear
> up to about 110 on the DS.
>
> So last night I sat down with the wheel and I decided to check the
> overall tension on the rim. DS was around 75 kgf!!!! How the heck
> did that happen?! I *know* I tensioned these properly as I am
> extremely anal about spoke tension.
>
> Anyhoo, I put in my last spare NDS CX-Ray spoke and tensioned up the
> wheel. Brought the DS up to 110 kgf and the NDS came up to about 70
> kgf. Interesting to note that even with the OC rim and the heads out
> radial NDS, the tension on the NDS was still only about 2/3 that of
> the DS. Some pretty significant dish on the Campy hubs (although I
> have never had a problem with broken spokes before with 3x lacing and
> non-OC rims).
It will be about 2/3 on a shimano hub as well. right sider flange is
only 1mm further to the left. It will never be the same as the DS
spoke tension if you use any freewheel or freehub type rear hub.
>
> So now I have two questions:
>
> 1. How the hell did the tension drop from 110 kgf to 75 kgf on the
> DS?!!
Spoke line straight after building, spoke elbows didn't bend more
under riding? I use my fingers to bend the spokeelbows toward the
flange on both sides before starting the build.
>
> 2. What is the chance these spokes now trashed, having been subjected
> to being ridden at the low tension for an indeterminate period of time
> (anywhere from 200 to 2000 miles)?
No problem with the spokes, I still think the rim is the issue.
>
> Hate to have to drop another ~$50 or so for a new set of the NDS CX-
> Rays (I am assuming the DS spokes are still good) if I don't have to.
Just use 14/15 spokes.
>
> Weird. Wonder if the spoke eyelets were not fully "seated"? And the
> stresses of riding the wheel caused them to seat in?
See above-seating the heads into the flange with a DT punch helps
also.
>
> Confusedly,
>
> D'ohBoy
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Date: 01 Sep 2007 16:31:55
From: datakoll
Subject: Re: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
well, next time after Dohboy lubes the hub, there's one principle not
tube forgotten: as weight reducts, fragility increases calling
YAAAHEEEEEWHOWHOWHO for increased inspection interval.
Same goes for first time build or second or thrid. Like you knew
right? and then went to sleep. GUTTERBALL!
never held the CX but specd the weight. do math? figure a wind up -
length formullah.
is it possible with spokes this light: rim maintains roundness over
spokes' pull then gives way in use?
compounding the stress relief process over time?
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Date: 01 Sep 2007 08:04:22
From: D'ohBoy
Subject: Followup and Two Q's Re: Opinions on Spoke Breakage Scenario
|
Weird.
Coupla things - in an earlier post I said that I could only get the
tension up to about 95 kgf before the rim started to distort. That
applied not to the rear but rather the front. I had gotten the rear
up to about 110 on the DS.
So last night I sat down with the wheel and I decided to check the
overall tension on the rim. DS was around 75 kgf!!!! How the heck
did that happen?! I *know* I tensioned these properly as I am
extremely anal about spoke tension.
Anyhoo, I put in my last spare NDS CX-Ray spoke and tensioned up the
wheel. Brought the DS up to 110 kgf and the NDS came up to about 70
kgf. Interesting to note that even with the OC rim and the heads out
radial NDS, the tension on the NDS was still only about 2/3 that of
the DS. Some pretty significant dish on the Campy hubs (although I
have never had a problem with broken spokes before with 3x lacing and
non-OC rims).
So now I have two questions:
1. How the hell did the tension drop from 110 kgf to 75 kgf on the
DS?!!
2. What is the chance these spokes now trashed, having been subjected
to being ridden at the low tension for an indeterminate period of time
(anywhere from 200 to 2000 miles)?
Hate to have to drop another ~$50 or so for a new set of the NDS CX-
Rays (I am assuming the DS spokes are still good) if I don't have to.
Weird. Wonder if the spoke eyelets were not fully "seated"? And the
stresses of riding the wheel caused them to seat in?
Confusedly,
D'ohBoy
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Date: 31 Aug 2007 06:15:34
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 31, 7:53 am, D'ohBoy <peteng...@yahoo.com > wrote:
> On Aug 30, 10:27 pm, "Mike Jacoubowsky" <mik...@ix.netcom.com> wrote:
>
>
>
> > >> did you stress relieve it jobst-style when building it?
>
> > > Yes. And again after the first spoke snapped (at the bend too!).
>
> > > D'ohBoy.
>
> > Stress-relieving isn't the whole story. Very important that, when you first
> > build it up, *before* putting much tension on the spokes, that you
> > physically bend the spokes over, at the head, so they take a nice, straight
> > path from hub to rim. Stress-relieving tends to accomplish this by default
> > (when grasping adjacent spokes and pulling them together), but you're best
> > off to first make sure that path is perfectly straight. This will make
> > tensioning the wheel easier as well, because you're not fighting the spoke
> > (forcing it to straighten out) as you tighten it. It's already straight.
>
> > --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com
>
> Being that the spokes are heads out and radially laced, the spoke line
> is absolutely straight. I am going to hack at the wheel more
> tonight.
>
> D'ohBoy
And I did stress relieve on the fully tensioned wheel.
D'ohBoy
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Date: 31 Aug 2007 05:53:31
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 10:27 pm, "Mike Jacoubowsky" <mik...@ix.netcom.com > wrote:
> >> did you stress relieve it jobst-style when building it?
>
> > Yes. And again after the first spoke snapped (at the bend too!).
>
> > D'ohBoy.
>
> Stress-relieving isn't the whole story. Very important that, when you first
> build it up, *before* putting much tension on the spokes, that you
> physically bend the spokes over, at the head, so they take a nice, straight
> path from hub to rim. Stress-relieving tends to accomplish this by default
> (when grasping adjacent spokes and pulling them together), but you're best
> off to first make sure that path is perfectly straight. This will make
> tensioning the wheel easier as well, because you're not fighting the spoke
> (forcing it to straighten out) as you tighten it. It's already straight.
>
> --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com
Being that the spokes are heads out and radially laced, the spoke line
is absolutely straight. I am going to hack at the wheel more
tonight.
D'ohBoy
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Date: 30 Aug 2007 19:10:18
From: Colin Campbell
Subject: Re: Opinions on Spoke Breakage Scenario
|
D'ohBoy wrote:
> All of a sudden, two spokes have broken in two weeks. Here are the
> details:
>
> - Broken spokes were Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hub
> - Spoke tension is very even - I use a tensiometer
> - Breakage is at the bend
> - 2000 or so miles on the set, problem-free prior
>
> I just don't get why this is happening. Bad spokes? I saw it
> suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> could cause this as well. DS is around 95 kgf. NDS is whatever it
> took to dish it properly (didn't do the conversion, just made sure
> they were evenly tensioned).
>
> Thanks for your input,
>
> D'ohBoy
>
I'm no expert, but the last time I had trouble with spokes breaking, the
LBS found that my Mavic rim had a cracked spoke hole. They ordered
another Mavic rim, and I kept breaking spokes. By the third spoke and
rebuild, the replacement rim showed _ten_ cracked spoke holes!
I got a Velocity Aerohead rim, as it was the only one I could find with
blue anodizing (Mavic stopped making them, the scoundrels!).
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Date: 30 Aug 2007 16:29:40
From: Ron Ruff
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 6:47 am, D'ohBoy <peteng...@yahoo.com > wrote:
> I just don't get why this is happening.
Are they laced heads-in or out? I'm thinking heads-in if you are
getting 1/2 tension on the NDS with an OC rim. I think it is important
to bend the spoke elbows so the spokes point towards the rim (or even
a little past) without bending stress. I do this on radial spokes with
a rubber hammer, when there is significant tension in the spokes but
not the final amount.
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Date: 30 Aug 2007 16:08:22
From: Michael Press
Subject: Re: Opinions on Spoke Breakage Scenario
|
In article
<1188478056.545183.109970@i13g2000prf.googlegroups.com >
,
D'ohBoy <petengail@yahoo.com > wrote:
> All of a sudden, two spokes have broken in two weeks. Here are the
> details:
>
> - Broken spokes were Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hub
> - Spoke tension is very even - I use a tensiometer
> - Breakage is at the bend
> - 2000 or so miles on the set, problem-free prior
>
> I just don't get why this is happening. Bad spokes? I saw it
> suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> could cause this as well. DS is around 95 kgf. NDS is whatever it
> took to dish it properly (didn't do the conversion, just made sure
> they were evenly tensioned).
>
> Thanks for your input,
You did not say that you stress relieved the
spokes of the fully tensioned wheel.
This is the step that most reduces the rate
of spoke fracture at the elbow.
--
Michael Press
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Date: 30 Aug 2007 14:15:07
From: Nate Knutson
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 12:22 pm, D'ohBoy <peteng...@yahoo.com > wrote:
> On Aug 30, 1:28 pm, Nate Knutson <biken...@riseup.net> wrote:
>
>
>
> > On Aug 30, 5:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
> > > All of a sudden, two spokes have broken in two weeks. Here are the
> > > details:
>
> > > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > > - 32 hole OCR rim/Record Hub
> > > - Spoke tension is very even - I use a tensiometer
> > > - Breakage is at the bend
> > > - 2000 or so miles on the set, problem-free prior
>
> > > I just don't get why this is happening. Bad spokes? I saw it
> > > suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> > > could cause this as well. DS is around 95 kgf. NDS is whatever it
> > > took to dish it properly (didn't do the conversion, just made sure
> > > they were evenly tensioned).
>
> > > Thanks for your input,
>
> > > D'ohBoy
>
> > did you stress relieve it jobst-style when building it?
>
> Yes. And again after the first spoke snapped (at the bend too!).
>
> D'ohBoy.
pretty weird.... you mentioned the idea that an under-spec spoke hole
could cause this. i have no idea about that -seems like snugger has to
be better and i don't see how it could increase fatigue to the spoke-
but maybe an over-spec spoke hole could cause this, the same way that
if you use a 1.8/1.6 spoke in a spoke hole that's way too large for
it, the elbow won't be properly supported. but this probably isn't
whats going on, of course.
seems like blaming the spokes is pretty reasonable.
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Date: 30 Aug 2007 20:30:47
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
|
pour some neatsfoot on the hub!
seriously. Nature wants free movement at the hub/spoke bend-
increasingly small with tension so lube as a hole or gap filling layer
both sides. The bend does not gaul, does not crack, as much.
THIS MESSAGE WAS BROUGHT TO YOU BY THE ANTI-SPOKE GAUL CRUSADE
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Date: 30 Aug 2007 12:22:37
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 1:28 pm, Nate Knutson <biken...@riseup.net > wrote:
> On Aug 30, 5:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
>
>
> > All of a sudden, two spokes have broken in two weeks. Here are the
> > details:
>
> > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > - 32 hole OCR rim/Record Hub
> > - Spoke tension is very even - I use a tensiometer
> > - Breakage is at the bend
> > - 2000 or so miles on the set, problem-free prior
>
> > I just don't get why this is happening. Bad spokes? I saw it
> > suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> > could cause this as well. DS is around 95 kgf. NDS is whatever it
> > took to dish it properly (didn't do the conversion, just made sure
> > they were evenly tensioned).
>
> > Thanks for your input,
>
> > D'ohBoy
>
> did you stress relieve it jobst-style when building it?
Yes. And again after the first spoke snapped (at the bend too!).
D'ohBoy.
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Date: 03 Sep 2007 13:18:51
From: daveornee
Subject: Re: Opinions on Spoke Breakage Scenario
|
D'ohBoy Wrote:
> On Aug 30, 1:28 pm, Nate Knutson <biken...@riseup.net> wrote:
> > On Aug 30, 5:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
> >
> >
> >
> > > All of a sudden, two spokes have broken in two weeks. Here ar
> the
> > > details:
> >
> > > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > > - 32 hole OCR rim/Record Hub
> > > - Spoke tension is very even - I use a tensiometer
> > > - Breakage is at the bend
> > > - 2000 or so miles on the set, problem-free prior
> >
> > > I just don't get why this is happening. Bad spokes? I saw it
> > > suggested elsewhere that a under-spec spoke hole (diameter) in th
> hub
> > > could cause this as well. DS is around 95 kgf. NDS is whateve
> it
> > > took to dish it properly (didn't do the conversion, just made sure
> > > they were evenly tensioned).
> >
> > > Thanks for your input,
> >
> > > D'ohBoy
> >
> > did you stress relieve it jobst-style when building it?
>
>
> Yes. And again after the first spoke snapped (at the bend too!).
>
> D'ohBoy.
How do you stress relieve "Jobst-style" with nearly flat spokes in
radial pattern?
I prefer the stabilizing methed described in Barnetts a.k.a. "th
Mavic" method by some. If there is any plastic deformation during thi
operation using the Barnett (a.k.a Mavic method) it will lower help i
correct spoke alignment and any "bedding in" of the hub interface a
the spoke holes.
CX-Ray spokes are very tough and have been fatigue tested as th
"longest lasting" of all Sapim spoke models. CX-Ray spokes ar
flattened Laser spokes.
I suspect that the CX-Ray spokes were not up to typical Sapim standard
and/or they suffered some damage.
I am not a fan of radial spoking in bicycle wheels, especially in th
rear wheel.
The slightest bit of torque transfer to the left rear flange woul
quicken the fatigue of both the hub flange and the spokes
--
daveornee
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| | |
Date: 30 Aug 2007 20:27:59
From: Mike Jacoubowsky
Subject: Re: Opinions on Spoke Breakage Scenario
|
>> did you stress relieve it jobst-style when building it?
>
>
> Yes. And again after the first spoke snapped (at the bend too!).
>
> D'ohBoy.
Stress-relieving isn't the whole story. Very important that, when you first
build it up, *before* putting much tension on the spokes, that you
physically bend the spokes over, at the head, so they take a nice, straight
path from hub to rim. Stress-relieving tends to accomplish this by default
(when grasping adjacent spokes and pulling them together), but you're best
off to first make sure that path is perfectly straight. This will make
tensioning the wheel easier as well, because you're not fighting the spoke
(forcing it to straighten out) as you tighten it. It's already straight.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| |
Date: 30 Aug 2007 11:28:03
From: Nate Knutson
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 5:47 am, D'ohBoy <peteng...@yahoo.com > wrote:
> All of a sudden, two spokes have broken in two weeks. Here are the
> details:
>
> - Broken spokes were Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hub
> - Spoke tension is very even - I use a tensiometer
> - Breakage is at the bend
> - 2000 or so miles on the set, problem-free prior
>
> I just don't get why this is happening. Bad spokes? I saw it
> suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> could cause this as well. DS is around 95 kgf. NDS is whatever it
> took to dish it properly (didn't do the conversion, just made sure
> they were evenly tensioned).
>
> Thanks for your input,
>
> D'ohBoy
did you stress relieve it jobst-style when building it?
|
| |
Date: 30 Aug 2007 15:56:02
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 11:52 am, datakoll <datak...@yahoo.com > wrote:
> using a magnifier, bright light, examine inside outside spoke bends
> for surface cracks. If you're not familiar with the process, root out
> worn spokes from the trash and compare.
> There's a dye for this sold at NAPA? entertaining for sure.
> The deal is, if cracks show, then scrap the spokes: beats reassembly
> and two more snaps.
> WPITA!
BTW, use my teflon wax hub spoke hole lube method! allows generic
spoke survival under load and with exotic hub/spoke combos increases
mechanism efficiency in the torque rod area.
bottoms up!
|
| | |
Date: 31 Aug 2007 20:50:53
From: Paul Kopit
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Thu, 30 Aug 2007 15:56:02 -0000, datakoll <datakoll@yahoo.com >
wrote:
>BTW, use my teflon wax hub spoke hole lube method! allows generic
>spoke survival under load and with exotic hub/spoke combos increases
>mechanism efficiency in the torque rod area.
Actually, I'd think that using your stuff on the nipples and/or spoke
holes in the rim would be more helpful.
Of late, I've discovered that not going through the spoke squeezing
technique when there is lower tension in the spokes, has resulted in
twisted spokes. Early on, the wheel goes out of true. The drive side
spokes release/unwind and the spokes on the drive side will break.
If the hub flanges are wide, you sometimes cannot get enought tension
on the NDS. I had that problem with Real Design hubs that were
reallymade for 135 mtb and they just spaced them to 130. Even with an
offset rim, the NDS tension was inadquate. I used those DT nips that
'lock' but it never was a great wheel.
|
| |
Date: 30 Aug 2007 15:52:46
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
|
using a magnifier, bright light, examine inside outside spoke bends
for surface cracks. If you're not familiar with the process, root out
worn spokes from the trash and compare.
There's a dye for this sold at NAPA? entertaining for sure.
The deal is, if cracks show, then scrap the spokes: beats reassembly
and two more snaps.
WPITA!
|
| |
Date: 30 Aug 2007 07:25:54
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
|
On Aug 30, 9:08 am, "Qui si parla Campagnolo-www.vecchios.com"
<pe...@vecchios.com > wrote:
> On Aug 30, 7:46 am, zencycle <zency...@bikerider.com> wrote:
>
>
>
> > On Aug 30, 8:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
> > > All of a sudden, two spokes have broken in two weeks. Here are the
> > > details:
>
> > > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > > - 32 hole OCR rim/Record Hub
> > > - Spoke tension is very even - I use a tensiometer
> > > - Breakage is at the bend
> > > - 2000 or so miles on the set, problem-free prior
>
> > > I just don't get why this is happening. Bad spokes? I saw it
> > > suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> > > could cause this as well. DS is around 95 kgf. NDS is whatever it
> > > took to dish it properly (didn't do the conversion, just made sure
> > > they were evenly tensioned).
>
> > > Thanks for your input,
>
> > > D'ohBoy
>
> > Without knowing the actual build technique, the first thing that comes
> > to mind is this - even spoke tension is good but high tension is bad
> > even if they're all the same. The spoke should have some spec on the
> > maximum tension. Keep well below this. The fact that you don't know
> > the NDS tension makes me suspect you had to over compensate to dish
> > the wheel. Try backing off the tension on the DS a bit, not so much
> > that the wheel gets soft, but enough so it's easier to dish without
> > really cranking the NDS. OCR rims were developed in part to eliminate
> > this problem, so checking the NDS tension should tell you if you have
> > over stressed to spokes.
>
> 95 kgf is somewhat low for this rim and spoe dimension doesn't matter,
> tension is tension..and is determined at max by the rim, not the
> spokes.
This is an IRD Cadence. Were you thinking of a Velocity Aerohead?
The rim has a minor out-of-round, and by minor, I mean less than 0.5
mm but not a flat spot per se.
I had to back off of the spoke tension as the rim started to distort
when I got much above my current level. Wondering if the rim just
ain't strong enough for my weight, even given the 32 spokes.
I guess I could try cranking it up again.
D'ohBoy
|
| |
Date: 30 Aug 2007 07:08:44
From: Qui si parla Campagnolo-www.vecchios.com
Subject: Re: Opinions on Spoke Breakage Scenario
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On Aug 30, 7:46 am, zencycle <zency...@bikerider.com > wrote:
> On Aug 30, 8:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
>
>
> > All of a sudden, two spokes have broken in two weeks. Here are the
> > details:
>
> > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > - 32 hole OCR rim/Record Hub
> > - Spoke tension is very even - I use a tensiometer
> > - Breakage is at the bend
> > - 2000 or so miles on the set, problem-free prior
>
> > I just don't get why this is happening. Bad spokes? I saw it
> > suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> > could cause this as well. DS is around 95 kgf. NDS is whatever it
> > took to dish it properly (didn't do the conversion, just made sure
> > they were evenly tensioned).
>
> > Thanks for your input,
>
> > D'ohBoy
>
> Without knowing the actual build technique, the first thing that comes
> to mind is this - even spoke tension is good but high tension is bad
> even if they're all the same. The spoke should have some spec on the
> maximum tension. Keep well below this. The fact that you don't know
> the NDS tension makes me suspect you had to over compensate to dish
> the wheel. Try backing off the tension on the DS a bit, not so much
> that the wheel gets soft, but enough so it's easier to dish without
> really cranking the NDS. OCR rims were developed in part to eliminate
> this problem, so checking the NDS tension should tell you if you have
> over stressed to spokes.
95 kgf is somewhat low for this rim and spoe dimension doesn't matter,
tension is tension..and is determined at max by the rim, not the
spokes.
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Date: 30 Aug 2007 07:06:49
From: Qui si parla Campagnolo-www.vecchios.com
Subject: Re: Opinions on Spoke Breakage Scenario
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D'ohBoy wrote:
> All of a sudden, two spokes have broken in two weeks. Here are the
> details:
>
> - Broken spokes were Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hub
> - Spoke tension is very even - I use a tensiometer
> - Breakage is at the bend
> - 2000 or so miles on the set, problem-free prior
>
> I just don't get why this is happening. Bad spokes? I saw it
> suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> could cause this as well. DS is around 95 kgf. NDS is whatever it
> took to dish it properly (didn't do the conversion, just made sure
> they were evenly tensioned).
>
> Thanks for your input,
>
> D'ohBoy
Is the rim round? That is, no deformity from riding? Broken spokes on
a used wheel generally means that at that spot, tension is low..kinda
like bending a coat hanger back and forth, back and firth...
Might raise tension to a wee bit above 100 kgf, and make sure tension
is even, even if it means you may have a slight 'flat' spot.
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Date: 30 Aug 2007 06:52:59
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
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On Aug 30, 8:46 am, zencycle <zency...@bikerider.com > wrote:
> On Aug 30, 8:47 am, D'ohBoy <peteng...@yahoo.com> wrote:
>
>
>
> > All of a sudden, two spokes have broken in two weeks. Here are the
> > details:
>
> > - Broken spokes were Radial-spoked CX-Ray NDS Rear
> > - 32 hole OCR rim/Record Hub
> > - Spoke tension is very even - I use a tensiometer
> > - Breakage is at the bend
> > - 2000 or so miles on the set, problem-free prior
>
> > I just don't get why this is happening. Bad spokes? I saw it
> > suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> > could cause this as well. DS is around 95 kgf. NDS is whatever it
> > took to dish it properly (didn't do the conversion, just made sure
> > they were evenly tensioned).
>
> > Thanks for your input,
>
> > D'ohBoy
>
> Without knowing the actual build technique, the first thing that comes
> to mind is this - even spoke tension is good but high tension is bad
> even if they're all the same. The spoke should have some spec on the
> maximum tension. Keep well below this. The fact that you don't know
> the NDS tension makes me suspect you had to over compensate to dish
> the wheel. Try backing off the tension on the DS a bit, not so much
> that the wheel gets soft, but enough so it's easier to dish without
> really cranking the NDS. OCR rims were developed in part to eliminate
> this problem, so checking the NDS tension should tell you if you have
> over stressed to spokes.
NDS is significantly lower than DS, as one would expect given the
difference in spoke angle (even with the OCR rim). I DO know that the
tension NDS on the tensiometer scale was around 1/2 that of the DS,
and DS ain't breaking. So the NDS spokes aren't "over stressed".
Thanks for your input.
D'ohBoy
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Date: 30 Aug 2007 06:46:32
From: zencycle
Subject: Re: Opinions on Spoke Breakage Scenario
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On Aug 30, 8:47 am, D'ohBoy <peteng...@yahoo.com > wrote:
> All of a sudden, two spokes have broken in two weeks. Here are the
> details:
>
> - Broken spokes were Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hub
> - Spoke tension is very even - I use a tensiometer
> - Breakage is at the bend
> - 2000 or so miles on the set, problem-free prior
>
> I just don't get why this is happening. Bad spokes? I saw it
> suggested elsewhere that a under-spec spoke hole (diameter) in the hub
> could cause this as well. DS is around 95 kgf. NDS is whatever it
> took to dish it properly (didn't do the conversion, just made sure
> they were evenly tensioned).
>
> Thanks for your input,
>
> D'ohBoy
Without knowing the actual build technique, the first thing that comes
to mind is this - even spoke tension is good but high tension is bad
even if they're all the same. The spoke should have some spec on the
maximum tension. Keep well below this. The fact that you don't know
the NDS tension makes me suspect you had to over compensate to dish
the wheel. Try backing off the tension on the DS a bit, not so much
that the wheel gets soft, but enough so it's easier to dish without
really cranking the NDS. OCR rims were developed in part to eliminate
this problem, so checking the NDS tension should tell you if you have
over stressed to spokes.
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Date: 30 Aug 2007 06:20:14
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
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On Aug 30, 8:18 am, datakoll <datak...@yahoo.com > wrote:
> first thing we gotta know is why ura using a leather saddle with
> Radial-spoked CX-Ray NDS Rear
> - 32 hole OCR rim/Record Hubs
Damn, man -
It's a Selle Italia SLR Gel Flow - and has a leather cover.
Dude. Again. Please. If you've nothing of value.
D'ohBoy
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Date: 30 Aug 2007 13:18:05
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
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first thing we gotta know is why ura using a leather saddle with
Radial-spoked CX-Ray NDS Rear
- 32 hole OCR rim/Record Hubs
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Date: 30 Aug 2007 05:56:41
From: D'ohBoy
Subject: Re: Opinions on Spoke Breakage Scenario
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On Aug 30, 7:50 am, datakoll <datak...@yahoo.com > wrote:
> have you noticed any skin problems? unusual moles, yellowing,
> thinninghair, lack of sex drive, do you have a craving for oats?
Gene:
Please. We get enough crap from Ed. Don't add to the stench. Trying
to figure out if I should be harassing my spoke vendor.
D'ohBoy
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Date: 30 Aug 2007 12:50:39
From: datakoll
Subject: Re: Opinions on Spoke Breakage Scenario
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have you noticed any skin problems? unusual moles, yellowing,
thinninghair, lack of sex drive, do you have a craving for oats?
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