straight gauge spoke in place of butted spoke

I have some spokes popping on the non drive side of a 10 yr old long wheel base recumbent. The wheel
is the original .... A while back, I replaced all the drive side spokes because of a chain suck that
pretty much made stress raisers on all the drive side spokes. That solved the breakage on that side
- btw- I replaced the double butted ones with straight guage. I am now popping non drive side spokes
on a regular basis- at the elbow. Is the wheel fatigued? After the replacement of the spokes, I
stress relieved the wheel and retensioned the spokes to take up any slight variation. I'm a 200 lb
guy and the bike carries about another 10 lbs of crap in the panniers. Tired wheel. I did notice
that the rim shows a hazy line that runs through the spoke holes- sort of a crazing in the finish.
Might that be an indication of the fatigue of the rim? Thanks Pat

 

On Tue, 15 Apr 2003 16:48:02 +0000, patrick mitchel wrote:

> I have some spokes popping on the non drive side of a 10 yr old long wheel base recumbent. The
> wheel is the original .... A while back, I replaced all the drive side spokes because of a chain
> suck that pretty much made stress raisers on all the drive side spokes. That solved the breakage
> on that side - btw- I replaced the double butted ones with straight guage. I am now popping non
> drive side spokes on a regular basis- at the elbow.

That is a classic fatigue break

> Is the wheel fatigued? After the replacement of the spokes, I stress relieved the wheel and
>retensioned the spokes to take up any slight variation. I'm a 200 lb guy and the bike carries about
>another 10 lbs of crap in the panniers. Tired wheel. I did notice that the rim shows a hazy line
>that runs through the spoke holes- sort of a crazing in the finish. Might that be an indication of
>the fatigue of the rim?

Crazing in the finish? How do you know that's the extent of it? I'd say the spokes need replacing,
as does the rim. But this time use butted spokes. Their better elasticity means that they will be
less likely to completely de-tension on the bottom. It is that which causes the fatigue. even having
only the right side plain gauge is enough, since that makes the wheel less able to bear your weight
without detensioning the bottom spokes.

The rim also sounds like it is cracking under the anodized surface. Bad idea, anodized wheels.

--

David L. Johnson

__o | Let's not escape into mathematics. Let's stay with reality. -- _`\(,_ | Michael Crichton
(_)/ (_) |

 

David L. Johnson <[email protected]> wrote in message news:[email protected]...
> On Tue, 15 Apr 2003 16:48:02 +0000, patrick mitchel wrote:
>
> > I have some spokes popping on the non drive side of a 10 yr old long
wheel
> > base recumbent. The wheel is the original .... A while back, I replaced
all
> > the drive side spokes because of a chain suck that pretty much made
stress
> > raisers on all the drive side spokes. That solved the breakage on that side - btw- I replaced
> > the double butted ones with straight guage. I am
now
> > popping non drive side spokes on a regular basis- at the elbow.
>
> That is a classic fatigue break
>
> > Is the wheel fatigued? After the replacement of the spokes, I stress relieved
the
> > wheel and retensioned the spokes to take up any slight variation. I'm a
200
> > lb guy and the bike carries about another 10 lbs of crap in the
panniers.
> > Tired wheel. I did notice that the rim shows a hazy line that runs
through
> > the spoke holes- sort of a crazing in the finish. Might that be an indication of the fatigue of
> > the rim?
>
> Crazing in the finish? How do you know that's the extent of it? I'd say the spokes need replacing,
> as does the rim. But this time use butted spokes. Their better elasticity means that they will be
> less likely to completely de-tension on the bottom. It is that which causes the fatigue. even
> having only the right side plain gauge is enough, since that makes the wheel less able to bear
> your weight without detensioning the bottom spokes.
>
> The rim also sounds like it is cracking under the anodized surface. Bad idea, anodized wheels.

When I shine a light on the wheel in the right fashion , there is a finish change along the line of
the spokes. Didn't notice it in the past couple of years so I can't say that it's a change, only
that I noticed it. But the change is so striking that it must be a fatigue thing.
>
> --
>
> David L. Johnson
>
> __o | Let's not escape into mathematics. Let's stay with reality. -- _`\(,_ | Michael Crichton
> (_)/ (_) |

 

patrick mitchel <[email protected]> wrote in message
news:[email protected]...
>
> David L. Johnson <[email protected]> wrote in message
> news:[email protected]...
> > On Tue, 15 Apr 2003 16:48:02 +0000, patrick mitchel wrote:
> >
> > > I have some spokes popping on the non drive side of a 10 yr old long
> wheel
> > > base recumbent. The wheel is the original .... A while back, I
replaced
> all
> > > the drive side spokes because of a chain suck that pretty much made
> stress
> > > raisers on all the drive side spokes. That solved the breakage on that side - btw- I replaced
> > > the double butted ones with straight guage. I
am
> now
> > > popping non drive side spokes on a regular basis- at the elbow.
> >
> > That is a classic fatigue break
> >
> > > Is the wheel fatigued? After the replacement of the spokes, I stress relieved
> the
> > > wheel and retensioned the spokes to take up any slight variation. I'm
a
> 200
> > > lb guy and the bike carries about another 10 lbs of crap in the
> panniers.
> > > Tired wheel. I did notice that the rim shows a hazy line that runs
> through
> > > the spoke holes- sort of a crazing in the finish. Might that be an indication of the fatigue
> > > of the rim?
> >
> > Crazing in the finish? How do you know that's the extent of it? I'd
say
> > the spokes need replacing, as does the rim. But this time use butted spokes. Their better
> > elasticity means that they will be less likely to completely de-tension on the bottom. It is
> > that which causes the
fatigue.
> > even having only the right side plain gauge is enough, since that makes the wheel less able to
> > bear your weight without detensioning the bottom spokes.
> >
> > The rim also sounds like it is cracking under the anodized surface. Bad idea, anodized wheels.
>
>
> When I shine a light on the wheel in the right fashion , there is a
finish
> change along the line of the spokes. Didn't notice it in the past couple
of
> years so I can't say that it's a change, only that I noticed it. But the change is so striking
> that it must be a fatigue thing.

By the way, it's a 27" rim so that sorta dates it...

> > --
> >
> > David L. Johnson
> >
> > __o | Let's not escape into mathematics. Let's stay with
reality. --
> > _`\(,_ | Michael Crichton (_)/ (_) |
> >
>

 

Patrick Mitchel writes:

> I have some spokes popping on the non drive side of a 10 yr old long wheel base recumbent.

You mean on the "left" side?

> A while back, I replaced all the drive side spokes because of a chain suck that pretty much made
> stress raisers on all the drive side spokes. That solved the breakage on that side - btw- I
> replaced the double butted ones with straight guage.

Is that an economy measure or availability matter? Especially with short spokes, using the thinnest
spokes available is to their advantage, but then you are aware of that or you wouldn't ask for
forgiveness here.

> I am now popping non drive side spokes on a regular basis- at the elbow. Is the wheel fatigued?

You mean the "right" side? All spoke failures that are not caused by an obvious trauma are fatigue
failures. I can't see you hub but I don't believe the spokes were adequately stress relieved, that
is if they were any good to begin with. Elbows are classic fatigue failures.

> After the replacement of the spokes, I stress relieved the wheel and re-tensioned the spokes to
> take up any slight variation. I'm a 200 lb guy and the bike carries about another 10 lbs of
> crap in the panniers. Tired wheel. I did notice that the rim shows a hazy line that runs
> through the spoke holes- sort of a crazing in the finish. Might that be an indication of the
> fatigue of the rim?

This must be an anodized rim, or you couldn't see crazing. However, not knowing the wheel size, kind
of rim, and number of spokes makes it hard to assess what went wrong. Visible crazing is normal for
anodized rims viewed with grazing incidence light.

Jobst Brandt [email protected] Palo Alto CA

 

>I did notice that the rim shows a hazy line that runs through
>> the spoke holes- sort of a crazing in the finish. Might that be an indication of the fatigue of
>> the rim?

Well, rims can fatigue and it shows up in some as little cracks starting at the spoke holes. I used
to get about 10,000 miles on MA-40s. I ride M-T519s now and get over 30,000 miles per rim.