cracked rim

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

Fishing for Jobstius brandtus, eh jimmy bean?

--
Tom Sherman - Post Free or Die!

In article <[email hidden]>,

Johnny Sunset said:

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

Tim McNamara said:

In article <[email hidden]>,

Johnny Sunset said:

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

Where is the picture of Jobst leaning in a hairpin curve?

Jobst in a recumbent position:
<http://mly.smugmug.com/photos/89226520-M.jpg>!!!

--
Tom Sherman - Post Free or Die!

Tim McNamara said:

In article <[email hidden]>,

Johnny Sunset said:

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp! now that's what happens with "tension as high as the rim can
bear"!!!

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

Johnny Sunset said:

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

Fishing for Jobstius brandtus, eh jimmy bean?

i don't eat old cod, johnny.

Tim McNamara said:

Quoted message said:

Quoted message said:

http://www.flickr.com/photos/38636024@N00/300118736/

Quoted message said:

Quoted message said:

Quoted message said:

for your enjoyment.

Quoted message said:

Quoted message said:

Fishing for Jobstius brandtus, eh jimmy bean?

Quoted message said:

He probably is, but it's an interesting photo nonetheless.

Quoted message said:

Here's another set of interesting photos:

Quoted message said:

http://mly.smugmug.com/gallery/1853614

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

The report on how and where that wheel was repaired is on rec.bicycles.rides

or:

http://tinyurl.com/ynzda7

Jobst Brandt

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

"note how the crack line runs with the extrusion axis. it originates at
the valve hole and does not extend to the eyelet bed at any point."

The crack looks like it runs along the risers that Mavic thoughtfully
provided for it. Lousy design.

Peter Cole said:

jim beam said:

http://www.flickr.com/photos/38636024@N00/300118736/
for your enjoyment.

"note how the crack line runs with the extrusion axis. it originates at
the valve hole and does not extend to the eyelet bed at any point."

The crack looks like it runs along the risers that Mavic thoughtfully
provided for it. Lousy design.

what risers are those peter?

jim beam said:

Tim McNamara said:

In article <[email hidden]>,

Johnny Sunset said:

"jim beam" wrote:
> http://www.flickr.com/photos/38636024@N00/300118736/
> for your enjoyment.
Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp! now that's what happens with "tension as high as the rim can
bear"!!!

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

So would you diagnose this rim failure (only 5000 miles on the wheel)
as over-tensioning also?

http://www.webstersabingdon.plus.com/damage/rim.jpg

I have no tensiometer, when originally built it went out of true due to
spoke unwinding, having loosened it off and re-tensioned I had no
problems until this happened.

Andrew Webster

In article <[email hidden]>,

jim beam said:

Tim McNamara said:

In article <[email hidden]>,

Johnny Sunset said:

"jim beam" wrote:
> http://www.flickr.com/photos/38636024@N00/300118736/
> for your enjoyment.
Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Not to lose sight of this rim, being the main topic of the thread, ISTR
a number of reports about Mavic MTB rims failing like this here in
r.b.t., and reports of Mavic's USA rep claiming that the failures were
caused by overinflation or running too-fat a tire.

Mavic's rims appear to have developed the metallurgic equivalent of
glass jaws with restrictions on spoke tension, inflation pressure and
tire size for the poor things to be usable.

I remember the Mavic rep refusing to warranty one of my broken rims
(Cosmic Expert) which failed after a mere 500 miles, because the
mechanic who had written up the sales receipt spelled "spokes" in the
cutesy neo-illiterate vernacular as "spox." Seriously. Mavic will say
anything to get out of warranty replacements, which to me suggests that
replacing broken rims is a significant revenue source (which further
suggests to me that they don't see their rims' propensity for early
failure as a problem).

Quoted message said:

Quoted message said:

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp!

I don't know if that was intentional or a typo but it's danged funny.
I'll have to remember that.

Quoted message said:

now that's what happens with "tension as high as the rim can bear"!!!

You appear to be making assumptions and not looking at the clear
evidence in the picture.

Quoted message said:

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

I don't necessarily agree, but since i have no idea what the spoke
tension was there's no way to be sure. Neither of us know that
information and I am not prepared to make the assumptions you do about
the spoke tension (and wheel ownership). On the other hand, I am not
going to rule out the possibility of extremely high spoke tension.

For another thing, look at the obvious age of the rim. It's been in
service a long time from all appearances. It's clear from the photos
that the rim brake track is very worn and that the metal basically just
tore once it got thin enough. Any rim will break like this if you thin
the sidewalls down enough, especially if the brake pads are positioned
to strike near the shoulder of the rim which seems to be the case here.
This is a rim that looks like it should have been taken out of service a
while earlier. There is a large lip at the outer edge of the brake
track that is quite visible.

Quoted message said:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

If you'd read Jobst's trip report you would have found out who the owner
of the rim is, and it's not Jobst. It is his friend's wheel.

BTW, the photos are excellent and worth leafing through. If those don't
convince someone to go ride in the Alps then nothing will. Man! And
they did my favorite pass in the Alps, the Col de la Cayolle. Looks
like it was a wonderful ride!

Andrew W said:

jim beam said:

Tim McNamara said:

In article <[email hidden]>,
"Johnny Sunset" <[email hidden]> wrote:

> "jim beam" wrote:
>> http://www.flickr.com/photos/38636024@N00/300118736/
>> for your enjoyment.
> Fishing for Jobstius brandtus, eh jimmy bean?
He probably is, but it's an interesting photo nonetheless.

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp! now that's what happens with "tension as high as the rim can
bear"!!!

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

So would you diagnose this rim failure (only 5000 miles on the wheel)
as over-tensioning also?

http://www.webstersabingdon.plus.com/damage/rim.jpg

I have no tensiometer, when originally built it went out of true due to
spoke unwinding,

if you load the rim to near yield, then increase that tension a little
more with a lateral load, the rim can yield. hence loosening that you
attribute to unwinding could be the precursor to what is clearly an
over-tension failure.

Quoted message said:

having loosened it off and re-tensioned I had no
problems until this happened.

Andrew Webster

next time

1. build with a tensiometer.
2. use the "mavic method" of bedding in the spokes
3. consider the use of thread lock.

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara said:

In article <[email hidden]>,
"Johnny Sunset" <[email hidden]> wrote:

> "jim beam" wrote:
>> http://www.flickr.com/photos/38636024@N00/300118736/
>> for your enjoyment.
> Fishing for Jobstius brandtus, eh jimmy bean?

He probably is, but it's an interesting photo nonetheless.

Not to lose sight of this rim, being the main topic of the thread,
ISTR a number of reports about Mavic MTB rims failing like this here
in r.b.t., and reports of Mavic's USA rep claiming that the failures
were caused by overinflation or running too-fat a tire.

Mavic's rims appear to have developed the metallurgic equivalent of
glass jaws with restrictions on spoke tension, inflation pressure and
tire size for the poor things to be usable.

I remember the Mavic rep refusing to warranty one of my broken rims
(Cosmic Expert) which failed after a mere 500 miles, because the
mechanic who had written up the sales receipt spelled "spokes" in the
cutesy neo-illiterate vernacular as "spox." Seriously. Mavic will
say anything to get out of warranty replacements, which to me
suggests that replacing broken rims is a significant revenue source
(which further suggests to me that they don't see their rims'
propensity for early failure as a problem).

Quoted message said:

Quoted message said:

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp!

I don't know if that was intentional or a typo but it's danged funny.
I'll have to remember that.

Quoted message said:

now that's what happens with "tension as high as the rim can bear"!!!

You appear to be making assumptions and not looking at the clear
evidence in the picture.

Quoted message said:

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of
the rim from the brake pad wear. At the shoulder of the rim, it
appears to have worn enough to allow the rim to separate. Looks
like an MA2 to my eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

I don't necessarily agree, but since i have no idea what the spoke
tension was there's no way to be sure. Neither of us know that
information and I am not prepared to make the assumptions you do about
the spoke tension (and wheel ownership). On the other hand, I am not
going to rule out the possibility of extremely high spoke tension.

For another thing, look at the obvious age of the rim. It's been in
service a long time from all appearances. It's clear from the photos
that the rim brake track is very worn and that the metal basically
just tore once it got thin enough. Any rim will break like this if
you thin the sidewalls down enough, especially if the brake pads are
positioned to strike near the shoulder of the rim which seems to be
the case here. This is a rim that looks like it should have been
taken out of service a while earlier. There is a large lip at the
outer edge of the brake track that is quite visible.

Quoted message said:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

If you'd read Jobst's trip report you would have found out who the
owner of the rim is, and it's not Jobst. It is his friend's wheel.

BTW, the photos are excellent and worth leafing through. If those
don't convince someone to go ride in the Alps then nothing will.
Man! And they did my favorite pass in the Alps, the Col de la
Cayolle. Looks like it was a wonderful ride!

No problems with Sun here.
--
Philip Lee

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara said:

In article <[email hidden]>,
"Johnny Sunset" <[email hidden]> wrote:

> "jim beam" wrote:
>> http://www.flickr.com/photos/38636024@N00/300118736/
>> for your enjoyment.
> Fishing for Jobstius brandtus, eh jimmy bean?
He probably is, but it's an interesting photo nonetheless.

Not to lose sight of this rim, being the main topic of the thread, ISTR
a number of reports about Mavic MTB rims failing like this here in
r.b.t., and reports of Mavic's USA rep claiming that the failures were
caused by overinflation or running too-fat a tire.

Mavic's rims appear to have developed the metallurgic equivalent of
glass jaws with restrictions on spoke tension, inflation pressure and
tire size for the poor things to be usable.

I remember the Mavic rep refusing to warranty one of my broken rims
(Cosmic Expert) which failed after a mere 500 miles, because the
mechanic who had written up the sales receipt spelled "spokes" in the
cutesy neo-illiterate vernacular as "spox." Seriously. Mavic will say
anything to get out of warranty replacements, which to me suggests that
replacing broken rims is a significant revenue source (which further
suggests to me that they don't see their rims' propensity for early
failure as a problem).

Quoted message said:

Quoted message said:

Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

holy carp!

I don't know if that was intentional or a typo but it's danged funny.
I'll have to remember that.

Quoted message said:

now that's what happens with "tension as high as the rim can bear"!!!

You appear to be making assumptions and not looking at the clear
evidence in the picture.

Quoted message said:

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:
http://mly.smugmug.com/gallery/1853614/1/89227219
or this:
http://mly.smugmug.com/gallery/1853614/1/89226684
- it's simply massive over-tension:

I don't necessarily agree, but since i have no idea what the spoke
tension was there's no way to be sure. Neither of us know that
information and I am not prepared to make the assumptions you do about
the spoke tension (and wheel ownership). On the other hand, I am not
going to rule out the possibility of extremely high spoke tension.

For another thing, look at the obvious age of the rim. It's been in
service a long time from all appearances. It's clear from the photos
that the rim brake track is very worn and that the metal basically just
tore once it got thin enough.

not the eyelet seats on both the inner and outer surfaces - no wear
going on there.

Quoted message said:

Any rim will break like this if you thin
the sidewalls down enough,

yes, but not in this way. failure from brake track wear is to have the
bead blow off.

Quoted message said:

especially if the brake pads are positioned
to strike near the shoulder of the rim which seems to be the case here.
This is a rim that looks like it should have been taken out of service a
while earlier. There is a large lip at the outer edge of the brake
track that is quite visible.

yeah - how anyone can ride that for so long and not notice the bumpy
braking defeats me.

Quoted message said:

Quoted message said:

and guess who owns the rim but professes to never have any tension
related problems?
http://mly.smugmug.com/gallery/1853614/1/89227772

If you'd read Jobst's trip report you would have found out who the owner
of the rim is, and it's not Jobst. It is his friend's wheel.

well, it's not the one his friend is pictured riding, that's for sure -
those are black anodized ambrosio rims with black sidewall continentals.
the tires on the busted rim however look identical to those used by
jobst - no tread, whitewall, visible bead ribbon, same rubber coverage...

Quoted message said:

BTW, the photos are excellent and worth leafing through. If those don't
convince someone to go ride in the Alps then nothing will. Man! And
they did my favorite pass in the Alps, the Col de la Cayolle. Looks
like it was a wonderful ride!

Johnny Walker writes:

http://www.flickr.com/photos/38636024@N00/300118736/

Quoted message said:

Quoted message said:

Quoted message said:

> for your enjoyment.

Quoted message said:

Quoted message said:

Quoted message said:

Fishing for Jobstius brandtus, eh jimmy bean?

Quoted message said:

Quoted message said:

He probably is, but it's an interesting photo nonetheless.

Quoted message said:

Quoted message said:

Here's another set of interesting photos:

Quoted message said:

Quoted message said:

http://mly.smugmug.com/gallery/1853614

Quoted message said:

http://mly.smugmug.com/photos/89227065-M.jpg

Quoted message said:

holy carp! now that's what happens with "tension as high as the rim
can bear"!!!

Quoted message said:

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of
the rim from the brake pad wear. At the shoulder of the rim, it
appears to have worn enough to allow the rim to separate. Looks
like an MA2 to my eyes, and looks to have been on borrowed time.

Quoted message said:

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:

http://mly.smugmug.com/gallery/1853614/1/89227219

Quoted message said:

or this:

http://mly.smugmug.com/gallery/1853614/1/89226684

Quoted message said:

- it's simply massive over-tension:

Quoted message said:

and guess who owns the rim but professes to never have any tension
related problems?

http://mly.smugmug.com/gallery/1853614/1/89227772

Reviewing those pictures without prejudicial glasses, it should be
apparent that this is a worn out rim with more than 20000 miles in all
kinds of weather and rough roads. If it was "simply massive
over-tension" there should be other spokes pulling out, or at least
ones with cracks in the rim. There weren't. The wheel had been
dinged badly enough that the spoke in question required higher than
average tension to true the wheel.

Meanwhile, my rims with deeply worn brake tracks survived this and the
two previous tours in the alps mainly because there wasn't much rain.

Jobst Brandt

Quoted message said:

Tim McNamara said:

Quoted message said:

> http://www.flickr.com/photos/38636024@N00/300118736/

Quoted message said:

Quoted message said:

> for your enjoyment.

Quoted message said:

Quoted message said:

Fishing for Jobstius brandtus, eh jimmy bean?

Quoted message said:

He probably is, but it's an interesting photo nonetheless.

Quoted message said:

Here's another set of interesting photos:

Quoted message said:

http://mly.smugmug.com/gallery/1853614

Quoted message said:

Looks like a very worn rim with a noticeable lip along the edge of the
rim from the brake pad wear. At the shoulder of the rim, it appears to
have worn enough to allow the rim to separate. Looks like an MA2 to my
eyes, and looks to have been on borrowed time.

The report on how and where that wheel was repaired is on rec.bicycles.rides

or:

http://tinyurl.com/ynzda7

Jobst Brandt

Dear Jobst,

Is this what you meant?

"Richard's rear wheel had pulled a spoke out of the rim, so he needed
a new one. Brian assured us that would be no problem because his bike
shop was super at such jobs. As it turned out there was only one
36-hole rim in the shop and it took the same spoke length as the old
one. For a mere 20EUR the job was done while I got some shuteye on
Brian's sofa."

http://groups.google.com/group/rec.bicycles.rides/browse_frm/thread/fac95b32d02234de/a31f3d1232d3820c?tvc=1&hl=en#a31f3d1232d3820c

The photo here looks as if the rim has broken around two spoke holes:

http://mly.smugmug.com/gallery/1853614/1/89227065

http://mly.smugmug.com/gallery/1853614/1/89227219

http://mly.smugmug.com/gallery/1853614/1/89227502

They seem like very different failures than the one that Jim Beam
posted:

http://www.flickr.com/photos/38636024@N00/300118736/

Jim's rim has a crack running from spoke hole to spoke hole, while
your friend Richard's rim seems to be pulling out in roughly circular
sections around separate spoke holes, with no connecting crack.

It's probably clear to other posters, but I don't understand why Jim's
and Richard's rims broke in such different ways.

Did Jim's rim crack the long way around, from spoke hole to spoke
hole, because spoke tension was too high on an unworn rim? An
alternate explanation is too wide a tire with too much pressure, a
combination that can split rims catastrophically like this:

http://members.cox.net/younggg/Wheel2.jpg

See this thread for details about too-wide tires at too-high pressure:

http://groups.google.com/group/rec.bicycles.tech/msg/d80be67f2878c22c

Did Richard's rim crack in circles around each spoke hole because the
sides were worn down by braking? This idea seems plausible, but then I
remember numerous pictures in which worn-down rim sides completely
separated from the central rim without the spokes pulling chunks out
of the middle:

http://home.comcast.net/~carlfogel/download/rim.jpg

http://home.comcast.net/~carlfogel/download/small_crack.JPG

http://home.comcast.net/~carlfogel/download/rimdetail.jpg

That's several views of David Van Tol's worn and failed rim, with no
apparent spoke hole cracks.

It would be nice to see some posts spelling out what people think is
going on in each case, and why the failures are so different.

Cheers,

Carl Fogel

Tim McNamara said:

...
Not to lose sight of this rim, being the main topic of the thread, ISTR
a number of reports about Mavic MTB rims failing like this here in
r.b.t., and reports of Mavic's USA rep claiming that the failures were
caused by overinflation or running too-fat a tire.

Mavic's rims appear to have developed the metallurgic equivalent of
glass jaws with restrictions on spoke tension, inflation pressure and
tire size for the poor things to be usable.

I remember the Mavic rep refusing to warranty one of my broken rims
(Cosmic Expert) which failed after a mere 500 miles, because the
mechanic who had written up the sales receipt spelled "spokes" in the
cutesy neo-illiterate vernacular as "spox." Seriously. Mavic will say
anything to get out of warranty replacements, which to me suggests that
replacing broken rims is a significant revenue source (which further
suggests to me that they don't see their rims' propensity for early
failure as a problem)....

butbutbut, unlike the well made rims from Alex, Sun and Velocity; Mavic
rims have European Heritage & Mystique [TM].

--
Tom Sherman - Post Free or Die!

Quoted message said:

Johnny Walker writes:

http://www.flickr.com/photos/38636024@N00/300118736/

Quoted message said:

Quoted message said:

>> for your enjoyment.

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> Fishing for Jobstius brandtus, eh jimmy bean?

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He probably is, but it's an interesting photo nonetheless.

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Here's another set of interesting photos:

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http://mly.smugmug.com/gallery/1853614

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http://mly.smugmug.com/photos/89227065-M.jpg

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holy carp! now that's what happens with "tension as high as the rim
can bear"!!!

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Looks like a very worn rim with a noticeable lip along the edge of
the rim from the brake pad wear. At the shoulder of the rim, it
appears to have worn enough to allow the rim to separate. Looks
like an MA2 to my eyes, and looks to have been on borrowed time.

Quoted message said:

ma2 indeed. but there's no way wear of the braking track alone can
cause distortion like this:

http://mly.smugmug.com/gallery/1853614/1/89227219

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or this:

http://mly.smugmug.com/gallery/1853614/1/89226684

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- it's simply massive over-tension:

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and guess who owns the rim but professes to never have any tension
related problems?

http://mly.smugmug.com/gallery/1853614/1/89227772

Reviewing those pictures without prejudicial glasses, it should be
apparent that this is a worn out rim with more than 20000 miles in all
kinds of weather and rough roads. If it was "simply massive
over-tension" there should be other spokes pulling out, or at least
ones with cracks in the rim. There weren't.

we've only got your word for that. the pictorial evidence we have
simply shows drive side spokes pulling out, a common enough occurrence
in over-tensioned wheels.

Quoted message said:

The wheel had been
dinged badly enough that the spoke in question required higher than
average tension to true the wheel.

so is it tension that pulled the spokes through or not? first you say
it's not tension, it's 20k miles of wear [which doesn't affect the
strength of the spoke beds btw], but then you say it /is/ excess tension
due to compensating for warping!

Quoted message said:

Meanwhile, my rims with deeply worn brake tracks survived this and the
two previous tours in the alps mainly because there wasn't much rain.

good for you. but does that explain how the "other guy"'s spokes pulled
through?

On Sun, 26 Nov 2006 15:57:05 -0600, Tim McNamara
<[email hidden]> wrote:

[snip]

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I remember the Mavic rep refusing to warranty one of my broken rims
(Cosmic Expert) which failed after a mere 500 miles, because the
mechanic who had written up the sales receipt spelled "spokes" in the
cutesy neo-illiterate vernacular as "spox."

[snip]

Dear Tim,

I know that it's wrong, but your "spox" story made a former English
teacher smile.

Cheers,

Carl Fogel

Johnny Walker writes:

http://www.flickr.com/photos/38636024@N00/300118736/

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>>> for your enjoyment.

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>> Fishing for Jobstius brandtus, eh jimmy bean?

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> He probably is, but it's an interesting photo nonetheless.

Quoted message said:

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> Here's another set of interesting photos:

http://mly.smugmug.com/gallery/1853614

http://mly.smugmug.com/photos/89227065-M.jpg

Quoted message said:

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holy carp! now that's what happens with "tension as high as the
rim can bear"!!!

Quoted message said:

Quoted message said:

Quoted message said:

> Looks like a very worn rim with a noticeable lip along the edge
> of the rim from the brake pad wear. At the shoulder of the rim,
> it appears to have worn enough to allow the rim to separate.
> Looks like an MA2 to my eyes, and looks to have been on borrowed
> time.

Quoted message said:

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ma2 indeed. but there's no way wear of the braking track alone
can cause distortion like this:

http://mly.smugmug.com/gallery/1853614/1/89227219

Quoted message said:

Quoted message said:

or this:

http://mly.smugmug.com/gallery/1853614/1/89226684

Quoted message said:

Quoted message said:

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- it's simply massive over-tension:

Quoted message said:

Quoted message said:

Quoted message said:

and guess who owns the rim but professes to never have any tension
related problems?

http://mly.smugmug.com/gallery/1853614/1/89227772

Quoted message said:

Quoted message said:

Reviewing those pictures without prejudicial glasses, it should be
apparent that this is a worn out rim with more than 20000 miles in
all kinds of weather and rough roads. If it was "simply massive
over-tension" there should be other spokes pulling out, or at least
ones with cracks in the rim. There weren't.

Quoted message said:

we've only got your word for that. the pictorial evidence we have
simply shows drive side spokes pulling out, a common enough
occurrence in over-tensioned wheels.

You have the pictures to review and there is only one spoke with rim
failure, which of course is enough and can lead to further failures
from larger load variation on adjacent spokes. Cyclic loading is what
causes such failures and Richard is no lightweight, being taller and
wider than I.

Quoted message said:

Quoted message said:

The wheel had been dinged badly enough that the spoke in question
required higher than average tension to true the wheel.

Quoted message said:

so is it tension that pulled the spokes through or not? first you
say it's not tension, it's 20k miles of wear [which doesn't affect
the strength of the spoke beds btw], but then you say it /is/ excess
tension due to compensating for warping!

You ask as one who does not understand the correlation between stress
cycles and material failure. Look it up in your metallurgical
library. Given enough time, rims fail and they do so by wearing out,
getting bent beyond repair or stress failures that typically occur at
spoke sockets (but not exclusively).

Quoted message said:

Quoted message said:

Meanwhile, my rims with deeply worn brake tracks survived this and
the two previous tours in the alps mainly because there wasn't much
rain.

Quoted message said:

good for you. but does that explain how the "other guy"'s spokes
pulled through?

Look at the pictures and use your imagination! Usually you seem to
have more answers than are requested on this subject.

Jobst Brandt