spoke breakage?

Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the bend.
Not often, say about 2/3 per year and it effects both front wheels equally.
Just come back from a ride today and noticed one in each front wheel broken
but I don't know if the breaks happened on this ride because I didn't check
before setting off ! Can't see any reason but I wonder if anyone has any
ideas?
I was just about to fit new spokes as I have done before but thought I would
post here for some "little gems" from you knowledgeable people.

Steve Watkin Wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non
butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the
bend.
Not often, say about 2/3 per year and it effects both front wheels
equally.
Just come back from a ride today and noticed one in each front wheel
broken
but I don't know if the breaks happened on this ride because I didn't
check
before setting off ! Can't see any reason but I wonder if anyone has
any
ideas?
I was just about to fit new spokes as I have done before but thought I
would
post here for some "little gems" from you knowledgeable people.
1. Brand and quality of the spokes.
2. Spoke alignment
3. Stress relief
4. Tension balancing
5. Stabilizing the build
6. Use of Double Butted spokes to spread the load over a larger number
of spokes.
Is the wheel involved using the hub brake?


--
daveornee

Steve Watkin wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the bend.
Not often, say about 2/3 per year and it effects both front wheels equally.
Just come back from a ride today and noticed one in each front wheel broken
but I don't know if the breaks happened on this ride because I didn't check
before setting off ! Can't see any reason but I wonder if anyone has any
ideas?
I was just about to fit new spokes as I have done before but thought I would
post here for some "little gems" from you knowledgeable people.

Low, erratic tension(bent rim, deformed rim)? Low tension initially,
then used, deforms rim. Generally a rim problem, not a spoke problem.
Try raising the tension, w/i limits, of course.

Is the wheel involved using the hub brake?

Yes

SW

Steve Watkin wrote:
Is the wheel involved using the hub brake?

Yes

Are the spokes that break generally leading or trailing... or have you
noticed?
It is only on the inside and not the outside?

Peter is probably right... too low of tension. You get a high lateral
force when cornering, and this will detension the inside spokes on the
outside wheel. The trailing-inside spokes will lose tension while
braking. The repeated stress of the spokes going slack and then
snapping tight will cause them to break after awhile... especially if
they weren't well built to start with.

daveornee wrote:
Steve Watkin Wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non
butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the
bend.
Not often, say about 2/3 per year and it effects both front wheels
equally.
Just come back from a ride today and noticed one in each front wheel
broken
but I don't know if the breaks happened on this ride because I didn't
check
before setting off ! Can't see any reason but I wonder if anyone has
any
ideas?
I was just about to fit new spokes as I have done before but thought I
would
post here for some "little gems" from you knowledgeable people.
1. Brand and quality of the spokes.
2. Spoke alignment
3. Stress relief
4. Tension balancing
5. Stabilizing the build
6. Use of Double Butted spokes to spread the load over a larger number
of spokes.
Is the wheel involved using the hub brake?


--
daveornee

Ya know Dave, I have taken more than a few machine built wheels that
came from J&B($30 retail type), really low end, no name straight gauge
spokes and then trued, rounded, tensioned and stress relieved the wheel
and these have seen lots of service for their owner. Having the brand
and quality of spoke at the top of your why they break list implies
noname spokes in a wheel that sees breakage IS the cause. In my
experience, poor builds is a much bigger problem with spokes breaking.

daveornee wrote:
Steve Watkin Wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non
butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the
bend.
Not often, say about 2/3 per year and it effects both front wheels
equally.
Just come back from a ride today and noticed one in each front wheel
broken
but I don't know if the breaks happened on this ride because I didn't
check
before setting off ! Can't see any reason but I wonder if anyone has
any
ideas?
I was just about to fit new spokes as I have done before but thought I
would
post here for some "little gems" from you knowledgeable people.
1. Brand and quality of the spokes.
2. Spoke alignment
3. Stress relief
4. Tension balancing
5. Stabilizing the build
6. Use of Double Butted spokes to spread the load over a larger number
of spokes.
Is the wheel involved using the hub brake?


--
daveornee

A second thought-Altho I use only butted spokes and think they are the
spoke to use, straight gauge spokes have in the past and continue to
make fine, long lasting wheels..again, it's about the build, IMO, of
course.

daveornee wrote:
Steve Watkin Wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non
butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the
bend.
Not often, say about 2/3 per year and it effects both front wheels
equally.
Just come back from a ride today and noticed one in each front wheel
broken
but I don't know if the breaks happened on this ride because I didn't
check
before setting off ! Can't see any reason but I wonder if anyone has
any
ideas?
I was just about to fit new spokes as I have done before but thought I
would
post here for some "little gems" from you knowledgeable people.
1. Brand and quality of the spokes.
2. Spoke alignment
3. Stress relief
4. Tension balancing
5. Stabilizing the build
6. Use of Double Butted spokes to spread the load over a larger number
of spokes.
Is the wheel involved using the hub brake?



What's "stabilizing the build"?

Steve Watkin wrote:
Tadpole 'bent trike with 20" wheel, 36 spoke, two cross, s/s non butted
spokes, S/A hub brakes.
Every so often I get one of the inboard front spokes broken at the bend.
Not often, say about 2/3 per year and it effects both front wheels equally.
Just come back from a ride today and noticed one in each front wheel broken
but I don't know if the breaks happened on this ride because I didn't check
before setting off ! Can't see any reason but I wonder if anyone has any
ideas?
I was just about to fit new spokes as I have done before but thought I would
post here for some "little gems" from you knowledgeable people.



There are only 2 "little gems".

1) Make sure your spokes are lying flat against the hub flange, any bow
will cause bending flex with every wheel rotation.

2) "Stress relieve" your spokes. This involves momentarily raising the
tension on a spoke by 50% or so. The effect is to remove residual
manufacturing and wheel building stresses. The procedure is described in
the rec.bike FAQ and/or Sheldon Brown's site.

Ron Ruff wrote:

The repeated stress of the spokes going slack and then
snapping tight will cause them to break after awhile... especially if
they weren't well built to start with.

As Jobst pointed out in a recent thread, spokes don't care about how
slack they go or how fast they regain tension. The absolute magnitude of
the stress variation and the static stress level are the only important
load factors in fatigue.