Spoke breakage at thread/nipple junction

On 9 Oct 2004 10:54:15 -0700, [email hidden] (John

Black) said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

Any thoughts on this would be appreciated.

Thanks!

Dear John,

As far as I know, the spokes aren't expected to twist back
and forth in the nipples--the oiling of the threads is just
to allow smooth, easy tightening and adjustment.

Most figures that I've seen suggest that about 9 out of 10
spokes break at the elbow, not at the nipple, so your steady
stream of nipple-end failures are odd.

If the nipples are indeed cocked away from the spoke line,
that might well explain the problem, since they'd be trying
to bend right at a thread.

This is probably a dumb question, but could the wheels have
been laced one hole off? That is, would the spoke/nipple
alignment be improved to normal if you moved all the spokes
one position around the rim?

Carl Fogel

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

A duff batch of spokes? There are some spoke patterns (e.g. 36h x4)
that can cause breakage at the nipple because the spoke is way out of
perpendicular with the rim, but 32h x3 is absolutely standard.

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple.

Nope that doesn't happen.

Quoted message said:

Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

That seems likely, possibly you installed the spokes in the wrong rim
holes, so the nipples are aiming in a different direction than the spokes.

Another likely issue is that perhaps the spokes are too short, so the
threads run out the bottom of the nipple, acting as a stress raiser
where the spoke is bent a wee bit as it exits the nipple.

Sheldon "Theories" Brown
+---------------------------------+
| If you understand everything, |
| you must be misinformed. |
| --Japanese Proverb |
+---------------------------------+
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

Zog The Undeniable said:

A duff batch of spokes? There are some spoke patterns (e.g. 36h x4)
that can cause breakage at the nipple because the spoke is way out of
perpendicular with the rim, but 32h x3 is absolutely standard.

Dear Zog,

As a Simpsons fan, I take exception to your use of "duff" in
a pejorative sense, a lapse of taste that offends even a
tee-totaller like myself--nothing matches the rich, smooth
taste of Duff, brewed in Springfield!

Such quaint Anglicisms must give way to the modern age!

A more sensitive (but deniable) poster would have spoken of
a "fudd" set of spokes, implying that they were no better
than the swill from in Shelbyville's Fudd Brewery.

(Posts in this vein should ease off after the Halloween
Treehouse of Horrors show.)

Carl Fogel

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

Any thoughts on this would be appreciated.

Thanks!

tell me more about your spokes. what brand are they? were they cut to
length by your lbs, then threaded or did you buy them in a sealed packet
- right length from factory?

also, what brand nipples do you have? some have a wider shaft than
others not allowing as much freedom to orientate correctly.

Quoted message said:

As a Simpsons fan, I take exception to your use of "duff" in
a pejorative sense, a lapse of taste that offends even a
tee-totaller like myself--nothing matches the rich, smooth
taste of Duff, brewed in Springfield!

El Duffo o Meurte!

Carl-<< This is probably a dumb question, but could the wheels have
been laced one hole off? That is, would the spoke/nipple
alignment be improved to normal if you moved all the spokes
one position around the rim? >><BR><BR>

That would be my guess. Look at the rim strip side of the rim and the holes are
offset one way or another. If the hole is on the right, rim strip side, they
are for the left side spokes.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

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

Quoted message said:

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple.

Nope that doesn't happen.

Quoted message said:

Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

That seems likely, possibly you installed the spokes in the wrong rim
holes, so the nipples are aiming in a different direction than the spokes.

Another likely issue is that perhaps the spokes are too short, so the
threads run out the bottom of the nipple, acting as a stress raiser
where the spoke is bent a wee bit as it exits the nipple.

Sheldon "Theories" Brown

A further query! The only spokes I have ever broken in this way were from
when I got a large stick (more a branch really) stuck in the wheel -and I
broke 3 spokes all at the nipple. Was it just chance, because every other
spoke I've ever broken was at the elbow?

Hugh Fenton

I had a similar experience with a spoke pattern-hub/rim combination
that resulted in a small angle between the nipple and spoke at the
thread terminus(not noticed at time of build). Spokes started breaking
at the end of the threads at approximately 1000 miles, one or two per
ride. Obviously the wheel was taken out of service. Sapim makes
nipples that allow a little line correction, and were the solution to
my problem after rebuild.

[email hidden] (John Black) wrote in message news:<[email hidden]>...

Quoted message said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

Any thoughts on this would be appreciated.

Thanks!

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

Any thoughts on this would be appreciated.

Thanks!

"A picture is worth a thousand words." Can you provide a detailed picture link that shows the angle of the spoke towards the hub hole in reference how the nipple is retained at the rim hole?

I am certain that you would not put the spokes in one hole off on this rim as it would totally defeat the OCR concept.

However, the Velocity Aerohead OCR rim his no eyelets, and each type of nipple interfaces differently with the spoke holes of this rim.

I would tend to follow the line of questioning that Jim Beam chose about the spokes themselves... or the bad batch theory.

Unless, when you stress relieved the spokes you either overshot or undershot the amount of tension required, you would have stress relieved the bend at the top of the nipples.
If you overshot when stress relieving, you would have foiled your earlier spoke alignment at the nipple end.
If you undershot in your stress relieving efforts, you would have created a weak point at the bend when spoke aligning that was not stress relieved sufficiently.
Since you said that you followed all the tenets of "the Bicycle Wheel" completely, it is very difficult to give you much additional guidance.

Sometimes DT Prohead or Sapim Polyax nipples can help in situations where spoke alignment at the rim end is an issue.

Zog The Undeniable said:

Quoted message said:

As a Simpsons fan, I take exception to your use of "duff" in
a pejorative sense, a lapse of taste that offends even a
tee-totaller like myself--nothing matches the rich, smooth
taste of Duff, brewed in Springfield!

El Duffo o Meurte!

Dear Zog,

That's the spirit!

(pun intended)

Even as children, Springfielders are willing to fight
Shelbyvillains over lemonade:

Bart: That lemon tree's a part of our town; and as kids, the
backbone of our economy. We'll get it back, or choke their
rivers with our dead!

http://www.snpp.com/episodes/scg-6.txt

Carl Fogel

Hugh Fenton said:

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

Quoted message said:

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple.

Nope that doesn't happen.

Quoted message said:

Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

That seems likely, possibly you installed the spokes in the wrong rim
holes, so the nipples are aiming in a different direction than the spokes.

Another likely issue is that perhaps the spokes are too short, so the
threads run out the bottom of the nipple, acting as a stress raiser
where the spoke is bent a wee bit as it exits the nipple.

Sheldon "Theories" Brown

A further query! The only spokes I have ever broken in this way were from
when I got a large stick (more a branch really) stuck in the wheel -and I
broke 3 spokes all at the nipple. Was it just chance, because every other
spoke I've ever broken was at the elbow?

Hugh Fenton

Dear Hugh,

Spokes occasionally break at the nipple end. (I've never
done it myself, despite numerous elbow breaks.)

When 76 spokes were cycled to failure in fatigue tests at
Stanford in 1984-85, 68 spokes failed at the elbow, while
only 8 spokes failed at the thread:

http://www.duke.edu/~hpgavin/papers/HPGavin-Wheel-Paper.pdf

Carl Fogel

John Black said:

I have been having spoke breakage recently that I thought people here
might help me to diagnose. The rear, drive-side spoke breaks just
where its threads enter the spoke nipple threads. This happens to one
spoke at a time, but is occurring with increasing frequency. I have
two identically built rear wheels that I use alternately, and each has
this problem, and it has arisen fairly recently. I built each one
myself, one being about a year old and the other a year and a half
old.

Each wheel is built with a Chorus hub, a Velocity OC rim (off-center),
with 32 15x16 gauge spokes in a cross 3 pattern with brass spoke
nipples. I built each wheel using the tenets of The Book, including
the use of motor oil to lubricate the spoke threads and the nipple/rim
interface. The wheels were properly stress-relieved. I ride on good
roads, don't subject the wheels to abuse except for hitting road
irregularities occasionally. I weigh about 143lbs.

I can think of two possible causes. One, that the motor oil
lubricating the spoke threads has lost its lubricity, preventing the
spoke from rotating that little bit within the nipple. Two, that the
nipple/rim interface does not allow the nipple to align parallel with
the spoke, causing a bending at the spoke/nipple junction.

That's a fairly unusual break. I associate that with wheels
built such that the left side spokes are laced to the
right-angled holes in the rim - a virtual impossibility with
your OC rims.
I don't believe that your choice of lubricant is relevant to
this odd failure but I do agree with you that something
about the nipple angle bears further investigation.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Wow, so many good thoughts! Thanks for all the input.

To Carl & Sheldon & Qui si parla campagnolo: The one hole off
theorum... A very good surmise. I thought I remembered that the
Velocity Aerohead OC rim had all spoke holes in a plane. I have taken
a look under the rim tape and all spoke holes do indeed appear on one
plane. Perhaps my sight cannot discern a slight offset for left versus
right side spokes, or an oriented spoke bed, on this rim. If so, this
theory lives.

To Zog: The bad spoke batch theorum... You know, I do remember
returning some of the spokes from this order (Colorado Cyclist)
because the lengths were not equal. It is possible (likely, now that I
have looked again at the wheel) that the lengths are still not all
equal. Back to this later.

To jim beam: Detail of spokes/nipples... They are DT from Colorado
Cyclist, same for the nipples. When I set out to build the wheel, I
wasn't even going to verify the spoke lengths they sent me. Good thing
I did, although I still didn't catch all the irregulars, as is obvious
to me now, looking at the variability of the spoke protrusion into the
nipples. I measure a 2mm variability on drive-side spokes.

To R Griffin: bad spoke/nipple angle theorum... I will consider
getting Sapim nipples.

To Dave: too much or little stress relief... It is possible I over
stressed, but spokes from the other side of the wheel (non-drive) are
not breaking. I will consider sapim or DT Prohead nipples. I do not
have a way to take a picture of this readily.

To Sheldon: spokes too short theorum... Hmmm. Well, they don't seem
short, although if they were then this would be a good possible cause
of the breakage. This has made me think that perhaps the problematic
spokes are just a bit too long. In fact, I still have the most recent
broken one, and I see that the spoke overshoots the nipple's end by 1
mm. If I thread a nipple onto my new spoke and overshoot 1mm, I have
used up all the rotation of the spoke in the nipple. Any more slight
rotation and I get resistance, and it must be from the non-threaded
section of the spoke trying to "thread" into the nipple. Could this be
causing the stress point? I think it could be.

Could this be?

John Black said:

Wow, so many good thoughts! Thanks for all the input.

To Carl & Sheldon & Qui si parla campagnolo: The one hole off
theorum... A very good surmise. I thought I remembered that the
Velocity Aerohead OC rim had all spoke holes in a plane. I have taken
a look under the rim tape and all spoke holes do indeed appear on one
plane. Perhaps my sight cannot discern a slight offset for left versus
right side spokes, or an oriented spoke bed, on this rim. If so, this
theory lives.

To Zog: The bad spoke batch theorum... You know, I do remember
returning some of the spokes from this order (Colorado Cyclist)
because the lengths were not equal. It is possible (likely, now that I
have looked again at the wheel) that the lengths are still not all
equal. Back to this later.

To jim beam: Detail of spokes/nipples... They are DT from Colorado
Cyclist, same for the nipples.

ok, quality ingredients. i'm not familiar with this rim, but you can
also check how the nipple beds are in the rim. you can carefully use an
oversize drill bit to countersink the tire side edge of the holes for
the nipple seats. you can also use a correct size drill, but cant it
slightly to bevel the hole in the direction of the spoke. both
operations require care not to remove too much material. per rgriffin,
the sperical seat sapim nipples are a good idea in this case.

Quoted message said:

When I set out to build the wheel, I
wasn't even going to verify the spoke lengths they sent me. Good thing
I did, although I still didn't catch all the irregulars, as is obvious
to me now, looking at the variability of the spoke protrusion into the
nipples. I measure a 2mm variability on drive-side spokes.

use damon rinard's spoke calculator and order what it says you need, not
what your retailer says, unless you're /real/ sure they know their stuff.

Quoted message said:

To R Griffin: bad spoke/nipple angle theorum... I will consider
getting Sapim nipples.

To Dave: too much or little stress relief... It is possible I over
stressed, but spokes from the other side of the wheel (non-drive) are
not breaking. I will consider sapim or DT Prohead nipples. I do not
have a way to take a picture of this readily.

To Sheldon: spokes too short theorum... Hmmm. Well, they don't seem
short, although if they were then this would be a good possible cause
of the breakage. This has made me think that perhaps the problematic
spokes are just a bit too long. In fact, I still have the most recent
broken one, and I see that the spoke overshoots the nipple's end by 1
mm. If I thread a nipple onto my new spoke and overshoot 1mm, I have
used up all the rotation of the spoke in the nipple. Any more slight
rotation and I get resistance, and it must be from the non-threaded
section of the spoke trying to "thread" into the nipple. Could this be
causing the stress point? I think it could be.

Could this be?

John Black wrote:
-snip- Detail of spokes/nipples... They are DT from Colorado

Quoted message said:

Cyclist, same for the nipples. When I set out to build the wheel, I
wasn't even going to verify the spoke lengths they sent me. Good thing
I did, although I still didn't catch all the irregulars, as is obvious
to me now, looking at the variability of the spoke protrusion into the
nipples. I measure a 2mm variability on drive-side spokes.

If your spokes exhibit a pattern of two long ones then two
short ones around the rim, you have built it with the
flanges one hole off. Although each flange is built
properly, the left flange is one spoke off from the right
flange. That would explain your breakage.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

John Black said:

Wow, so many good thoughts! Thanks for all the input.

To Carl & Sheldon & Qui si parla campagnolo: The one hole off
theorum... A very good surmise. I thought I remembered that the
Velocity Aerohead OC rim had all spoke holes in a plane. I have taken
a look under the rim tape and all spoke holes do indeed appear on one
plane. Perhaps my sight cannot discern a slight offset for left versus
right side spokes, or an oriented spoke bed, on this rim. If so, this
theory lives.

<SNIP>?

I took a look at the Velocity Aerohead OCR rims I have.
There is an offset you can see from the side facing toward the bub as well as the rim tape side.
Not only does the theory live, but it helps explain the problem and solution.

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

Quoted message said:

John Black said:

Wow, so many good thoughts! Thanks for all the input.

To Carl & Sheldon & Qui si parla campagnolo: The one hole off
theorum... A very good surmise. I thought I remembered that the
Velocity Aerohead OC rim had all spoke holes in a plane. I have taken
a look under the rim tape and all spoke holes do indeed appear on one
plane. Perhaps my sight cannot discern a slight offset for left versus
right side spokes, or an oriented spoke bed, on this rim. If so, this
theory lives.

<SNIP>?

I took a look at the Velocity Aerohead OCR rims I have.
There is an offset you can see from the side facing toward the bub as
well as the rim tape side.
Not only does the theory live, but it helps explain the problem and
solution.

I built an aerohead oc recently and recall that the holes were indeed
offset\angled alternating left and right, as usual. It may be harder
to discern this via looking underneath the rim strip now that the
wheel is built. Try looking at the spoke hole where the spoke broke
and see if you can tell that the hole is drilled at an angle.