Aerohead rim cracking

Song said:

Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

The sheen looks like anodising to me too. However, IME this type of anodising doesn't usually cause
a problem compared to the hard black stuff. Probably the rim is just underweight and underspecified
for this many spokes and this much spoke tension. In other words, it's a lemon.

On Sun, 15 Feb 2004 10:26:05 -0800, "Song" <[email hidden]>

Quoted message said:

Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

thanks Song

All the Aeroheads I've seen have these cracks after a few weeks. In my experience they stop growing
and remain no problem for a long, long time (many years).

Yes, that blue looks anodized to me too. I wouldn't worry about it.

what's your spoke tension?

Song said:

Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

thanks Song

Quoted post said:

Originally posted by Song
Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

thanks Song

Well, radial spoking and 24 spokes doesn't start off on the best feet. Radial spoking is harder on hubs, spokes, and rims.
I have used Velocity Aeorhead rims down to 28 spokes with 2X spoking for fronts with no cracks after over 20,000 miles. I have also had very good results with their OCR 32 hole rim spoked 3X with DT Competition DB spokes for rears.
I use their powder coated rims.
I would call and ask Velocity USA their opinion. They are in Michigan. Phone🙁616)243.3400
[email hidden]
They may not be very interested in an eBay deal that is sour.

jim beam said:

Song said:

...Aerohead rim ... hairline cracks ... on at least one side of every spoke hole on the rim.

Quoted message said:

what's your spoke tension?

The Velocity Aerohead is an unusual rim. The space inside is slightly smaller than the width of many
common spoke nipples. So as the spokes are tensioned the nipple head acts like a wedge and puts high
lateral force on the inside rim wall. This often leads to deformation and almost always to very
early cracking, aided by the knife edge where the side of the spoke hole cuts through the thin side
wall of the rim.

So while excessive spoke tension in ordinary rims hastens cracking, in this rim merely assembling it
into a reasonable wheel hastens rim cracking.

But as I noted in another post, the cracks, once formed, take a very long time to grow beyond a few
millimeters. Speculating here, but maybe the nipple head wedges deeper and comes to rest against the
thick wall in nose of the rim?

I think Velocity might have redesigned the Aerohead rim since this one was made.

dianne_1234 <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

All the Aeroheads I've seen have these cracks after a few weeks. In my experience they stop
growing and remain no problem for a long, long time (many years).

Yes, that blue looks anodized to me too. I wouldn't worry about it.

Hi, are you talking about Velocity brand aerohead rims? If so, is this still a problem? And do they
have the same problem withe Deep V?

Any info will be appreciated. Jeff

jim beam said:

what's your spoke tension?

What does it matter? This question is irrelevant.

It's clear from the photos, the rim is a goner and should be replaced. There is no such thing as a
"cosmetic" crack in an anodized rim, as the crack *will* propogate into the base metal and the rim
will fail.

Quoted message said:

The Velocity Aerohead is an unusual rim. The space inside is slightly smaller than the width of
many common spoke nipples. So as the spokes are tensioned the nipple head acts like a wedge and
puts high lateral force on the inside rim wall.

I thought that is why it's recommended to use nipple washers on these rims.

"dianne_1234" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

jim beam said:

Song said:

...Aerohead rim ... hairline cracks ... on at least one side of every spoke hole on the rim.

Quoted message said:

what's your spoke tension?

The Velocity Aerohead is an unusual rim. The space inside is slightly smaller than the width of
many common spoke nipples. So as the spokes are tensioned the nipple head acts like a wedge and
puts high lateral force on the inside rim wall. This often leads to deformation and almost always
to very early cracking, aided by the knife edge where the side of the spoke hole cuts through the
thin side wall of the rim.

So while excessive spoke tension in ordinary rims hastens cracking, in this rim merely assembling
it into a reasonable wheel hastens rim cracking.

But as I noted in another post, the cracks, once formed, take a very long time to grow beyond a
few millimeters. Speculating here, but maybe the nipple head wedges deeper and comes to rest
against the thick wall in nose of the rim?

I think Velocity might have redesigned the Aerohead rim since this one was made.

On Sun, 15 Feb 2004 10:26:05 -0800, "Song" <[email hidden]> may

have said:

Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

Anodizing is very brittle. It will crack easily when the underlying metal deforms. I'd only be
seriously worried myself if the crack actually goes through the metal. You may be able to determine
if this is the case by taling a couple of spokes out and examining the nipple hole with a magnifier.
A dye-check of the area would probably be misleading, unfortunately. If you can confirm that the
crack extends through, I would be underwhelmed with the concept of putting this rim into service. If
the cracks are in the anodization only, I'd say it's purely a judgement call. I'm not sure which way
I'd jump in that case.

Another poster's suggestion to call the manufacturer and ask about the issue seems well-founded.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.

"Song" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Hi

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

thanks Song

I have the old American Classic wheels built on Velocity Aero heads. Same issue with the micro-
cracks on the rear wheel. My Radial front has no signs of cracking. I replaced my rear with a CXP21
rim. The wheel is shot.

-a

Tim McNamara said:

jim beam said:

what's your spoke tension?

What does it matter? This question is irrelevant.

In most rims higher tension leads to earlier fatigue cracking. Modified Goodman curve, etc.

Quoted message said:

It's clear from the photos, the rim is a goner and should be replaced. There is no such thing as a
"cosmetic" crack in an anodized rim, as the crack *will* propogate into the base metal and the rim
will fail.

In my experience, this rim (Velocity Aerohead) has been durable with cracks exactly like the ones in
the photo. I think this might be so because I imagine the stress might decrease for two reasons:
1. the wall gets thicker away from the edge of the spoke hole, and
2. the spoke nipple comes to rest on the inside of the rim.

Even if my guesses 1 and 2 are wrong, my experience is still real.

Wei Song said:

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on eBay,
and when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the
rim itself?
- on at least one side of every spoke hole on the rim.

Quoted message said:

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

Quoted message said:

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced Aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Quoted message said:

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

This rim is anodized and the crack is IN the aluminum, anodized coatings seldom being more than
0.001" thick. This problem cannot be solved with washers, there being no space to fit a washer
inside this rim. It is possible that the inside of the rim has a counterbore that is too small for
the spoke nipple head and that it has wedged itself into a splitting position but that doesn't hold
much hope because such a nipple could not be readily turned to tension spokes. Therefore, I believe
the cracks are on the way to getting larger with use.

One should wonder why sockets and eyelets were used with success on 300g rims of old. The claim is
that we have better materials today but the cracks don't support that claim.

Jobst Brandt [email hidden]

On Tue, 17 Feb 2004 05:35:59 GMT, [email hidden] may

have said:

One should wonder why sockets and eyelets were used with success on 300g rims of old. The claim is
that we have better materials today but the cracks don't support that claim.

I have no doubt the answer to that is simple: profit.

(Not that the presence of eyelets and sockets alone will keep certain vexatious rims from
cracking...)

--
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.

Quoted message said:

Wei Song said:

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on eBay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer

-snip-

Quoted message said:

Quoted message said:

The seller has kindly offered compensation

-snip-

Quoted message said:

stanford.eduaerohead.htmOpen ↗

-snip-

Quoted message said:

Quoted message said:

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

Quoted message said:

This rim is anodized and the crack is IN the aluminum, anodized coatings seldom being more than
0.001" thick. This problem cannot be solved with washers, there being no space to fit a washer
inside this rim. It is possible that the inside of the rim has a counterbore that is too small for
the spoke nipple head and that it has wedged itself into a splitting position but that doesn't
hold much hope because such a nipple could not be readily turned to tension spokes. Therefore, I
believe the cracks are on the way to getting larger with use.

One should wonder why sockets and eyelets were used with success on 300g rims of old. The claim is
that we have better materials today but the cracks don't support that claim.

Jobst Brandt [email hidden]

I'm pretty sure that's the older discontinueed Aerohead. It got a cross-section change a couple of
years ago and is now offered without cut sides in silver or black anodize finish. Colors are painted
with cut sides

I'm with Jobst - return this wheel.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Song said:

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on ebay, and
when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the rim
itself? - on at least one side of every spoke hole on the rim.

stanford.eduaerohead.htmOpen ↗

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

If I still had it I would send you an "after" picture of an Aerohead (DT 14, 3X, 32) with a nice
line of three distorted spoke holes, spoke on the center one cracked clear out of the rim. This was
in theory a well-built wheel though it was one heck of a pothole-smack that did it in. You should
have heard the "Tonnnnnnnnnggggg", who dropped the piano?

Visible cracks on rims strike me as the kind of thing where you just don't bother to guess if
it'll work.

-Tad "what is all the fuss about Aeroheads?" (0 for 3)

Tad Borek said:

Quoted message said:

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on eBay,
and when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the
rim itself? - on at least one side of every spoke hole on the rim.

stanford.eduaerohead.htmOpen ↗

Quoted message said:

Quoted message said:

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced Aerohead user or experienced with heat-treated rims in general, please tell me
whether this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Quoted message said:

If I still had it I would send you an "after" picture of an Aerohead (DT 14, 3X, 32) with a nice
line of three distorted spoke holes, spoke on the center one cracked clear out of the rim. This
was in theory a well-built wheel though it was one heck of a pothole-smack that did it in. You
should have heard the "Tonnnnnnnnnggggg", who dropped the piano?

Are you suggesting that striking a pot hole ripped the spokes out? There must have been something
else at work because radial overloads only slacken spokes and do not significantly increase tension
in any spokes unless the arc of the rim is severely flattened (permanent large dent).

Quoted message said:

Visible cracks on rims strike me as the kind of thing where you just don't bother to guess if
it'll work.

I think such failures can be observed and carefully ridden home if suitable care is taken. Let's not
forget that the highest tension is in spokes not in the load affected zone (about six inches at the
ground contact point) and that it is the lower tension as spokes pass the ground contact zone that
causes fatigue failures, the ones in question here. This is not a forced failure condition as you
imply by the paragraph above. Failures that occur at such bumps in the road do so as the last straw,
so to speak, in stress cycles when the wheel becomes unloaded after the shock.

Jobst Brandt [email hidden]

don't you think it interesting to see cracks perpendicular to maximum compressive stress?

Quoted message said:

Wei Song said:

I recently bought a front wheel with a radially-laced, straight-pull 24h Aerohead rim on eBay,
and when it arrived, to my dismay, there were hairline cracks in the anodized layer - perhaps the
rim itself?
- on at least one side of every spoke hole on the rim.

Quoted message said:

The seller has kindly offered compensation, but in order to reach agreement we agree on how
extensive it should be, he asked me to get a second opinion. So here I humbly seek all your second
opinions. If you have some time, check out the link below:

stanford.eduaerohead.htmOpen ↗

Quoted message said:

The wheel itself is very true, no hops, does not appear to have been abused. If you're an
experienced Aerohead user or experienced with heat-treated rims in general, please tell me whether
this damage is strictly cosmetic, or is an omen of catastrophic things to come.

Quoted message said:

Note: blue Aerohead rims are supposed to be powder-coated, but this seems to be an older model and
sure looks like anodiztion to me. But perhaps you can tell?

This rim is anodized and the crack is IN the aluminum, anodized coatings seldom being more than
0.001" thick. This problem cannot be solved with washers, there being no space to fit a washer
inside this rim. It is possible that the inside of the rim has a counterbore that is too small for
the spoke nipple head and that it has wedged itself into a splitting position but that doesn't
hold much hope because such a nipple could not be readily turned to tension spokes. Therefore, I
believe the cracks are on the way to getting larger with use.

One should wonder why sockets and eyelets were used with success on 300g rims of old. The claim is
that we have better materials today but the cracks don't support that claim.

Jobst Brandt [email hidden]

Jim Beam / Jack Daniels said:

Don't you think it interesting to see cracks perpendicular to maximum compressive stress?

You are making an unwarranted assumption, especially in light of the opening crack. Instead of
posing rhetorical questions, you might add some perspective to this subject.

No, I don't find that interesting because that shows that the principal stress at this location
is tension from nipple outward bending force. As others have reported, star-burst failures have
also occurred.

Jobst Brandt [email hidden]

Quoted message said:

Tad Borek said:

If I still had it I would send you an "after" picture of an Aerohead (DT 14, 3X, 32) with a nice
line of three distorted spoke holes, spoke on the center one cracked clear out of the rim. This
was in theory a well-built wheel though it was one heck of a pothole-smack that did it in. You
should have heard the "Tonnnnnnnnnggggg", who dropped the piano?

Are you suggesting that striking a pot hole ripped the spokes out? There must have been something
else at work because radial overloads only slacken spokes and do not significantly increase
tension in any spokes unless the arc of the rim is severely flattened (permanent large dent).

Ya, there was a lot going on really. I've pondered the exact dynamics of that failure. Modeling the
pothole edge as a right angle that is struck by a wheel ~2" sunk into it wouldn't be too far off.
The tire (Vred) was well-inflated but very likely not at 145 psi or whatever the sidewall says.
Wheel almost new, my guess is the tension was a bit low. I was on the drops at ~high 20's mph and
unfortunately focused on the bumper in front rather than the pavement below.

The rim indeed ended up heart-shaped, w/a crisp indendation where the edge hit. The largest spoke
hole crack looked like someone had taken tin shears, cut a 1/8" gash, then needle-nose pliers, and
bent one of the resulting "corners" outward. I don't recall that spoke's relationship to the
flattened point on the rim.

Quoted message said:

Quoted message said:

Visible cracks on rims strike me as the kind of thing where you just don't bother to guess if
it'll work.

I think such failures can be observed and carefully ridden home if suitable care is taken.

Yes though I rode carefully, and was missing the old brake QR of Campy SR. Who came up with those
buttons anyway?

I wouldn't push that though, that was my point about this ebayed wheel. Send it back, wheels
are cheap!

Let's not forget that the highest tension is

Quoted message said:

in spokes not in the load affected zone (about six inches at the ground contact point) and that it
is the lower tension as spokes pass the ground contact zone that causes fatigue failures, the ones
in question here. This is not a forced failure condition as you imply by the paragraph above.
Failures that occur at such bumps in the road do so as the last straw, so to speak, in stress
cycles when the wheel becomes unloaded after the shock.

I had dismissed it as a wheel that was just poorly built. But seeing the OP's photos makes me
reconsider whether the shock brought out a rim defect, or whether the load exceeded the capabilities
of the materials for that particular rim. Despite the generally good reviews I haven't had good luck
with that rim.

-Tad