Aerohead rim cracking

Discussion in 'Cycling Equipment' started by Song, Feb 15, 2004.

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  1. Song

    Song Guest

    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:

    http://www.stanford.edu/~weisong/aerohead.htm

    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
     
    Tags:


  2. Song wrote:

    > 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:
    >
    > http://www.stanford.edu/~weisong/aerohead.htm
    >
    > 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.
     
  3. Dianne_1234

    Dianne_1234 Guest

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

    >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:
    >
    >http://www.stanford.edu/~weisong/aerohead.htm
    >
    >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.
     
  4. Jim Beam

    Jim Beam Guest

    what's your spoke tension?

    Song wrote:
    > 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:
    >
    > http://www.stanford.edu/~weisong/aerohead.htm
    >
    > 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
     
  5. daveornee

    daveornee New Member

    Joined:
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    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 protected]
    They may not be very interested in an eBay deal that is sour.
     
  6. Dianne_1234

    Dianne_1234 Guest

    On Sun, 15 Feb 2004 21:58:23 GMT, jim beam <[email protected]> wrote:

    >Song wrote:
    >> ...Aerohead rim ... hairline cracks ... on at least one side of every spoke hole on the rim.

    >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.
     
  7. Jeff Starr

    Jeff Starr Guest

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

    >
    >
    > 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
     
  8. Tim McNamara

    Tim McNamara Guest

    jim beam <[email protected]> writes:

    > 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.
     
  9. Ronald

    Ronald Guest

    > 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 protected]> wrote in message
    news:[email protected]...
    > On Sun, 15 Feb 2004 21:58:23 GMT, jim beam <[email protected]> wrote:
    >
    > >Song wrote:
    > >> ...Aerohead rim ... hairline cracks ... on at least one side of every spoke hole on the rim.
    >
    > >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.
     
  10. Werehatrack

    Werehatrack Guest

    On Sun, 15 Feb 2004 10:26:05 -0800, "Song" <[email protected]> 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:
    >
    >http://www.stanford.edu/~weisong/aerohead.htm

    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.
     
  11. "Song" <[email protected]> wrote in message news:<[email protected]>...
    > 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:
    >
    > http://www.stanford.edu/~weisong/aerohead.htm
    >
    > 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
     
  12. Dianne_1234

    Dianne_1234 Guest

    On Sun, 15 Feb 2004 18:50:33 -0600, Tim McNamara
    <[email protected]> wrote:

    >jim beam <[email protected]> writes:
    >
    >> 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.

    >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.
     
  13. Jobst Brandt

    Jobst Brandt Guest

    Wei Song writes:

    > 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:

    http://www.stanford.edu/~weisong/aerohead.htm

    > 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?

    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 protected]
     
  14. Werehatrack

    Werehatrack Guest

    On Tue, 17 Feb 2004 05:35:59 GMT, [email protected] 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.
     
  15. A Muzi

    A Muzi Guest

    > Wei Song writes:
    >
    >
    >>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-
    >>The seller has kindly offered compensation
    -snip-
    > http://www.stanford.edu/~weisong/aerohead.htm
    -snip-
    >>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?

    [email protected] wrote:
    > 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 protected]

    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
     
  16. Tad Borek

    Tad Borek Guest

    Song wrote:
    > 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.
    >
    > http://www.stanford.edu/~weisong/aerohead.htm
    >
    > 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)
     
  17. Jobst Brandt

    Jobst Brandt Guest

    Tad Borek writes:

    >> 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.

    http://www.stanford.edu/~weisong/aerohead.htm

    >> 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?

    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).

    > 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 protected]
     
  18. Jim Beam

    Jim Beam Guest

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

    [email protected] wrote:
    > Wei Song writes:
    >
    >
    >>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:
    >
    >
    > http://www.stanford.edu/~weisong/aerohead.htm
    >
    >
    >>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?
    >
    >
    > 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 protected]
     
  19. Jobst Brandt

    Jobst Brandt Guest

    Jim Beam / Jack Daniels writes:

    > 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 protected]
     
  20. Tad Borek

    Tad Borek Guest

    [email protected] wrote:
    > Tad Borek writes:
    >>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.

    >>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
    > 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
     
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