spoke breakage at nipple side

I've got some 14/15/14 double butted spokes laced to a chorus rear hub
and a Ritchey Aero OCR rim. I've broken two spokes since building the
wheel (about 2 thousand miles) and I've looked into it. It seems that
the spoke nipples are perpendicular to the rim, while the spokes enter
the rim at an angle (obviously). The end of the spoke nipple is
touching the outside of the spoke and the two spokes have broken where
the tread stops. The non-drive side are the ones breaking.

I'm pretty sure I have the spokes going to the proper hole in the rim
as the drive side looks fine. The spokes entering from the non-drive
side that are crossing on the outside have a distinct angle change
between the spoke and the nipple.

Why?

Should I remove the 8 spokes that are outside-crossing on the non-drive
side and drill the rim such that the nipple will be able to angle
towards the spokes?

Anything else I might be doing wrong?

wrote:
I've got some 14/15/14 double butted spokes laced to a chorus rear hub
and a Ritchey Aero OCR rim. I've broken two spokes since building the
wheel (about 2 thousand miles) and I've looked into it. It seems that
the spoke nipples are perpendicular to the rim, while the spokes enter
the rim at an angle (obviously). The end of the spoke nipple is
touching the outside of the spoke and the two spokes have broken where
the tread stops. The non-drive side are the ones breaking.

I'm pretty sure I have the spokes going to the proper hole in the rim
as the drive side looks fine. The spokes entering from the non-drive
side that are crossing on the outside have a distinct angle change
between the spoke and the nipple.

Why?

Should I remove the 8 spokes that are outside-crossing on the non-drive
side and drill the rim such that the nipple will be able to angle
towards the spokes?

Anything else I might be doing wrong?

Is the rim new? I ran into this problem on a used rim that I bought and
built up. My suspicion was that the rim may have ben built with pulling
spokes in the opposite direction and that they had been seated in the
opposite direction, pulling or bending the ferrules slightly with them.
I have had success with using smooth-jaw pliers to grasp the nipples
and pull them over so that they would line up with the spoke.
Incredibly, it _seems_ to have worked, because I stopped breaking
spokes, but it may have just been serendipitous. (I did lubricate the
nipple threads and seats before the build.)

I think it's possible that regular "stress-relieving" may actually
exacerbate this problem by creating more of a kink at the point where
the spoke meets the nipple, localizing stress there. OTOH, maybe
stress-relieving with enough force should have lined up the nipples
with the spokes, although I can't visualize that effect- it seems to me
that the spoke should still kink at the nipple and stay kinked as more
force is applied.

This is mostly just theorizing over a correlation between straightening
the spoke line and a reduction in breakage. Brandt will no doubt jump
in now and tell me I am full of crap.

There are no ferrules on the Ritchey Aero OCR rim, by the way.

wrote:
There are no ferrules on the Ritchey Aero OCR rim, by the way.

There were, however, on my rim. Maybe your rim itself deformed, but you
yourself noted that the nipple was perpendicular to the rim and the
spoke was not. That's an issue whether or not the rim is new or used,
with or without ferrules.

wrote:
I've got some 14/15/14 double butted spokes laced to a chorus rear hub
and a Ritchey Aero OCR rim. I've broken two spokes since building the
wheel (about 2 thousand miles) and I've looked into it. It seems that
the spoke nipples are perpendicular to the rim, while the spokes enter
the rim at an angle (obviously). The end of the spoke nipple is
touching the outside of the spoke and the two spokes have broken where
the tread stops. The non-drive side are the ones breaking.

I'm pretty sure I have the spokes going to the proper hole in the rim
as the drive side looks fine. The spokes entering from the non-drive
side that are crossing on the outside have a distinct angle change
between the spoke and the nipple.

Why?

Should I remove the 8 spokes that are outside-crossing on the non-drive
side and drill the rim such that the nipple will be able to angle
towards the spokes?

Anything else I might be doing wrong?

Some nipples align themselves in the rim better than others (they have
rounded seats).

If this doesn't happen, Jobst's book suggests deliberately bending the
spokes at the nipple during building to cold-set them and prevent any
movement in use, which can lead to fatigue.

If your wheel is 4x, rebuild it 3x.

Zog The Undeniable wrote:

If this doesn't happen, Jobst's book suggests deliberately bending the
spokes at the nipple during building to cold-set them and prevent any
movement in use, which can lead to fatigue.

Interesting. The OP said that the spokes were on the non-drive side. I
don't see how it could be tensioned enough to prevent movement because
of the dish.

anonymous writes:

If this doesn't happen, Jobst's book suggests deliberately bending
the spokes at the nipple during building to cold-set them and
prevent any movement in use, which can lead to fatigue.

Interesting. The OP said that the spokes were on the non-drive
side. I don't see how it could be tensioned enough to prevent
movement because of the dish.

Left rear spokes generally have a greater lateral angle than right
side spokes and because spokes do not break from tension (it causing
stresses far below yield), but rather residual stress overlayed on
even moderate tension, these spokes most often fail on a wheel that
has not been stress relieved.

This occurs both at elbows and threads because both places receive
bending during lacing and subsequent tensioning that reaches and
maintains yield stress.

Residual stress is the basic cause of spoke failure in bicycle wheels.

Jobst Brandt

wrote:
anonymous writes:

If this doesn't happen, Jobst's book suggests deliberately bending
the spokes at the nipple during building to cold-set them and
prevent any movement in use, which can lead to fatigue.

Interesting. The OP said that the spokes were on the non-drive
side. I don't see how it could be tensioned enough to prevent
movement because of the dish.

Left rear spokes generally have a greater lateral angle than right
side spokes and because spokes do not break from tension (it causing
stresses far below yield), but rather residual stress overlayed on
even moderate tension, these spokes most often fail on a wheel that
has not been stress relieved.

This occurs both at elbows and threads because both places receive
bending during lacing and subsequent tensioning that reaches and
maintains yield stress.

Residual stress is the basic cause of spoke failure in bicycle wheels.

Maybe, but in my case I did stress relieve the wheels to the best of my
ability, which involved using my heavy padded motorcycle gloves with
the rivets on the palm to squeeze the spoke pairs together with just
about all my strength, repeated until the process didn't change the
truing of the wheel. I was pretty frustrated by the whole thing and I
changed from alloy nipples to brass with little if any improvement. My
process of straightening the nipple-spoke line with pliers seems to
have fixed the problem. I admit that since I don't have anything to
check tension it is possible that tension was not high enough, but I
think it probably was.

It still seems to me that a kink in the spoke at the point where the
nipple and spoke meet would be the point where cyclical fatigue would
eventually result in failure if the spoke was flexed once per
revolution.

I never had a problem with spokes breaking in the wheels I built before
I had heard of stress-relieving but they did go out of true all the
time and seemed to dent more easily as well. I think that
stress-relieving is a part of building good wheels, but I am not
convinced that the spoke breakage problem in this case is caused by
residual stress that can be relieved by the normal method of stress
relief. Maybe using the pliers to straighten the spoke-nipple line is
another method of stress-relief that addresses this specific problem?

anonymous writes:

If this doesn't happen, Jobst's book suggests deliberately
bending the spokes at the nipple during building to cold-set them
and prevent any movement in use, which can lead to fatigue.

Interesting. The OP said that the spokes were on the non-drive
side. I don't see how it could be tensioned enough to prevent
movement because of the dish.

Left rear spokes generally have a greater lateral angle than right
side spokes and because spokes do not break from tension (it
causing stresses far below yield), but rather residual stress
overlayed on even moderate tension, these spokes most often fail on
a wheel that has not been stress relieved.

This occurs both at elbows and threads because both places receive
bending during lacing and subsequent tensioning that reaches and
maintains yield stress.

Residual stress is the basic cause of spoke failure in bicycle wheels.

Maybe, but in my case I did stress relieve the wheels to the best of
my ability, which involved using my heavy padded motorcycle gloves
with the rivets on the palm to squeeze the spoke pairs together with
just about all my strength, repeated until the process didn't change
the truing of the wheel. I was pretty frustrated by the whole thing
and I changed from alloy nipples to brass with little if any
improvement. My process of straightening the nipple-spoke line with
pliers seems to have fixed the problem. I admit that since I don't
have anything to check tension it is possible that tension was not
high enough, but I think it probably was.

Well??? If the problem is fixed let's rejoice and chalk that up to
experience.

It still seems to me that a kink in the spoke at the point where the
nipple and spoke meet would be the point where cyclical fatigue
would eventually result in failure if the spoke was flexed once per
revolution.

I don't understand why you think that. Unsupported bends cause
failure but not supported kinks in the spoke. Without that kink, the
spoke was bending near the end of the threads with every wheel
revolution. With the kink, spokes just pull from the spoke nipple
rather than around a bend at an angle to the last support point.

I never had a problem with spokes breaking in the wheels I built
before I had heard of stress-relieving but they did go out of true
all the time and seemed to dent more easily as well. I think that
stress-relieving is a part of building good wheels, but I am not
convinced that the spoke breakage problem in this case is caused by
residual stress that can be relieved by the normal method of stress
relief. Maybe using the pliers to straighten the spoke-nipple line
is another method of stress-relief that addresses this specific
problem?

You are probably correct in that assessment, but unsupported bends in
spokes cause spokes to bend. Such flexing readily puts high tensile
stress cycles in the outside surface of the bend and compressive
stress on the inside to cause fatigue failures.

Jobst Brandt

wrote:
I've got some 14/15/14 double butted spokes laced to a chorus rear hub
and a Ritchey Aero OCR rim. I've broken two spokes since building the
wheel (about 2 thousand miles) and I've looked into it. It seems that
the spoke nipples are perpendicular to the rim, while the spokes enter
the rim at an angle (obviously). The end of the spoke nipple is
touching the outside of the spoke and the two spokes have broken where
the tread stops. The non-drive side are the ones breaking.

I suspect the wheel is laced into the wrong holes. Look at the outside
of the rim. The holes are offset toward one side or the other. If off
set to the right, they are for spokes on the left side of the hub, as
the drilling process must be pointed that way.