broke a spoke 2

Michael said:

It set me to thinking: the kick-stand could have caused the earlier spoke
failure. What if I happened to roll slightly *backward* - after stopping on an
uphill incline, say - and the end of the kick-stand happened to be just so
...... ?

The ancient steel-rod kickstands with the outward-angled end were less
likely to cause that than the currently-popular Greenfield, but even
the Greenfield would have a hard time snagging a spoke. The end
usually is tapered to a chisel edge by wear, if nothing else, and the
likelihood is high that the spoke would bounce off the tip. Still,
it's conceivable that a snag could happen, but I really think you'd
have noticed it at the time.
--
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Michael said:

Broke my first spoke fairly recently. I don't remember hearing it break so I
don't know exactly when and how it broke. I discovered it while trying to find
the source of a very annoying ping-ping-ping.

I went for a short spin right after replacing that spoke; just putting the bike
away unridden after repairing something so important seems Not Right to me.
Just a liesurely around-the-block spin. THe ping-ping-ping was gone. So I hit
a short rough stretch - unfilled asphalt cracks - and suddenly I hear a
snap-snap-snap. The last time I heard that sound it turned out to be a broken
bearing in the rear hub. Rats! I walked home.

Could not aggravate the problem with the bike on a stand. Darn it. Opened up
the hub; scrubbed out bearings and grease; inspected bearings and races.
Everything was in order. OK, maybe it's the front hub; can't always tell
exactly where noises originate. But everything was fine in the front hub.
Re-assemble; re-pack; go for a spin. Some imaginative gyrations showed that I
could make the SNAP-SNAP-SNAP come and go pretty much at will. Leaning my body
hard to the left, bike hard to the right, brought it on; leaning hard to the
right, bike hard to the left, made it stop. Rough pavement could bring it on;
rough pavement could make it stop.

Went home and put bike on the stand. Gave the rear wheel a hard spin, in
disgust more than as a diagnostic precursor. Shazam! The SNAP-SNAP was right
in my face. It was the sound of a spoke smacking the business part of a
kick-stand. Kick-stand mounting bolt was slightly loose. That, in addition to
a sloppy fit between kick-stand and its mount, made it j-u-s-t possible for
kick-stand to contact one spoke.

It set me to thinking: the kick-stand could have caused the earlier spoke
failure. What if I happened to roll slightly *backward* - after stopping on an
uphill incline, say - and the end of the kick-stand happened to be just so
...... ?

You have another 6 (or 7?) spokes to break, before it all settles down.
Whatever caused the 1st spoke to break will also cause all the others
in the same symmetry position to fail.

I'll bet it is the forward-going left-hand rear spokes. These commonly
fatigue due to cyclic bending-stress at the flange--the spoke makes
contact with the flange as well as the hole and so has to bend through
a very short distance.

It could be the rear-giong spokes--if your wheel is laced with them in
the out-going position, rather than the forward-goers.

bill said:

Michael said:

Broke my first spoke fairly recently. I don't remember hearing it break so I
don't know exactly when and how it broke. I discovered it while trying to find
the source of a very annoying ping-ping-ping.

I went for a short spin right after replacing that spoke; just putting the bike
away unridden after repairing something so important seems Not Right to me.
Just a liesurely around-the-block spin. THe ping-ping-ping was gone. So I hit
a short rough stretch - unfilled asphalt cracks - and suddenly I hear a
snap-snap-snap. The last time I heard that sound it turned out to be a broken
bearing in the rear hub. Rats! I walked home.

Could not aggravate the problem with the bike on a stand. Darn it. Opened up
the hub; scrubbed out bearings and grease; inspected bearings and races.
Everything was in order. OK, maybe it's the front hub; can't always tell
exactly where noises originate. But everything was fine in the front hub.
Re-assemble; re-pack; go for a spin. Some imaginative gyrations showed that I
could make the SNAP-SNAP-SNAP come and go pretty much at will. Leaning my body
hard to the left, bike hard to the right, brought it on; leaning hard to the
right, bike hard to the left, made it stop. Rough pavement could bring it on;
rough pavement could make it stop.

Went home and put bike on the stand. Gave the rear wheel a hard spin, in
disgust more than as a diagnostic precursor. Shazam! The SNAP-SNAP was right
in my face. It was the sound of a spoke smacking the business part of a
kick-stand. Kick-stand mounting bolt was slightly loose. That, in addition to
a sloppy fit between kick-stand and its mount, made it j-u-s-t possible for
kick-stand to contact one spoke.

It set me to thinking: the kick-stand could have caused the earlier spoke
failure. What if I happened to roll slightly *backward* - after stopping on an
uphill incline, say - and the end of the kick-stand happened to be just so
...... ?

Quoted message said:

You have another 6 (or 7?) spokes to break, before it all settles down.
Whatever caused the 1st spoke to break will also cause all the others
in the same symmetry position to fail.

I hope not. Replacing that spoke was not fun or particularly easy. (I disn't
have the correct spanner for removing cassette; had to improvise.)

Quoted message said:

I'll bet it is the forward-going left-hand rear spokes.

Correct.

--
Michael

Michael said:

The SNAP-SNAP was right
in my face. It was the sound of a spoke smacking the business part of a
kick-stand. Kick-stand mounting bolt was slightly loose. That, in addition to
a sloppy fit between kick-stand and its mount, made it j-u-s-t possible for
kick-stand to contact one spoke.

It set me to thinking: the kick-stand could have caused the earlier spoke
failure. What if I happened to roll slightly *backward* - after stopping on an
uphill incline, say - and the end of the kick-stand happened to be just so
...... ?

I don't understand why the kickstand would hit only one spoke. Was the
wheel way out of true? Or possibly the lacing pattern (e.g.,
"over-over-under" with respect to the spoke crossings) different for
that spoke?

I assume the kickstand is on the left side of the bike, and I thought I
read that the broken spoke was on the right side. Something doesn't
seem to add up.

Art Harris

Art Harris said:

Michael said:

The SNAP-SNAP was right
in my face. It was the sound of a spoke smacking the business part of a
kick-stand. Kick-stand mounting bolt was slightly loose. That, in addition to
a sloppy fit between kick-stand and its mount, made it j-u-s-t possible for
kick-stand to contact one spoke.

It set me to thinking: the kick-stand could have caused the earlier spoke
failure. What if I happened to roll slightly *backward* - after stopping on an
uphill incline, say - and the end of the kick-stand happened to be just so
...... ?

I don't understand why the kickstand would hit only one spoke. Was the
wheel way out of true? Or possibly the lacing pattern (e.g.,
"over-over-under" with respect to the spoke crossings) different for
that spoke?

I assume the kickstand is on the left side of the bike, and I thought I
read that the broken spoke was on the right side. Something doesn't
seem to add up.

Art Harris

Lacing is correct. Rim isn't exactly true; there's some runout. Only one spoke
was striking when I found the problem. Sometimes several would strike while I
was riding, giving a really nasty snaping sound, nasty enough to put horrible
images in my head of bearing fragments scooting over each other and scoring the
races in the process.

Kickstand is indeed on left. My OP didn't specify which side the broken spoke
was on but it was on the left also.

Torqued the kickstand bolt yesterday. Did 24 pleasantly quiet and uneventful
miles today.

--
Michael