Impending rim failure (spoke pull-through)??

http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.


Is this normal? Scary? Immediately dangerous? To me, it seems to
indicate that there's a bit too much tension in the spokes. But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true.

Thanks,
\\paul
--
Paul M. Hobson
..:change the f to ph to reply:.

Paul M. Hobson wrote:
http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.


Is this normal? Scary? Immediately dangerous? To me, it seems to
indicate that there's a bit too much tension in the spokes. But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true.

Thanks,
\\paul

what you're looking at is deformation caused by the spoke nipple head.
spoke nipples vary slightly in profile and size from manufacturer to
manufacturer, model to model, and clearly whatever you have isn't an
exact match for the rim drilling.

that said however, the cracks in the anodizing that you can see [that's
what you're looking at] are oriented perpendicular to the rim's
traditional axial rim cracking mode and are therefore not a problem.
just ride until the braking surfaces wear out.

On May 10, 8:39*am, "Paul M. Hobson" wrote:
http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. *According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. *On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. *In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.

Is this normal? *Scary? *Immediately dangerous? *To me, it seems to
indicate that there's a bit too much tension in the spokes. *But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, *which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true..

Thanks,
\\paul
--
Paul M. Hobson
.:change the f to ph to reply:.

Basically, this is normal, you can keep using the wheel.

This is a known issue with Velocity Aerohead rims. The valley inside
the rim is too narrow for many spoke nipple heads, so the rim bulges
and crazes the anodizing. Typically, with use you might eventually get
little cracks emanating laterally from the edges of the spoke holes.
These cracks seem to relieve the outward stress in the rim and usually
grow to about a millimeter or two in length. Eventually they reach a
stable length and don't get any bigger, even with more use. Maybe it's
the substantial circumferential compressive stress that keeps them
from growing...

On May 10, 7:39*am, "Paul M. Hobson" wrote:
http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. *According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. *On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. *In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.

Is this normal? *Scary? *Immediately dangerous? *To me, it seems to
indicate that there's a bit too much tension in the spokes. *But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, *which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true..

Thanks,
\\paul
--
Paul M. Hobson
.:change the f to ph to reply:.

Normal, not a problem.

On Sat, 10 May 2008 09:39:52 -0400, "Paul M. Hobson"
may have said:

http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.


Is this normal? Scary? Immediately dangerous? To me, it seems to
indicate that there's a bit too much tension in the spokes. But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true.

The anodizing on the surface of the aluminum in the area of the spoke
has crazed, which is entirely normal. Anodization causes formation of
a very brittle layer of material on the surface of the metal, and this
shatters if the substrate flexes much. The process of bringing the
wheel up to tension will cause that much distortion of the area around
the spoke hole, and the result is what you see. Nothing to worry
about.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Thanks for the responses everyone. I'm glad to hear that this is normal
and not cause for alarm. To be honest, it's actually pretty surprising
to me with my limited knowledge of wheels and aluminum's material
properties -- but good new nonetheless!

\\paul


Werehatrack wrote:
On Sat, 10 May 2008 09:39:52 -0400, "Paul M. Hobson"
may have said:

http://www.flickr.com/photos/p_myron...06432/sizes/l/

You'll see a silver Velocity Aerohead rim. According to the builder,
the rim was stress relieved (JB's method) and tensioned to 100 - 110
kgf. On both sides of each spoke hole, the aluminum appears to be under
significant stress by the discoloration (lighter color).

Capturing this with a photograph was tough as the lighting has to be
just right to notice it even with the wheel in front of you. In the
photo, you can only see it at the left and middle holes, but this is
happening at all 32 holes.


Is this normal? Scary? Immediately dangerous? To me, it seems to
indicate that there's a bit too much tension in the spokes. But I'm
definitely among the uninitiated when it comes to wheel building -- all
of my rims up to this point have been anodized black, which might be
hiding this from me.

FWIW, the wheel has taken a good bit of abuse already and still quite true.

The anodizing on the surface of the aluminum in the area of the spoke
has crazed, which is entirely normal. Anodization causes formation of
a very brittle layer of material on the surface of the metal, and this
shatters if the substrate flexes much. The process of bringing the
wheel up to tension will cause that much distortion of the area around
the spoke hole, and the result is what you see. Nothing to worry
about.



--
Paul M. Hobson
..:change the f to ph to reply:.