black anodized hubs bad?

Discussion in 'Cycling Equipment' started by Eric Bazan, Apr 19, 2003.

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  1. Eric Bazan

    Eric Bazan Guest

    I've heard about anodized rims being more prone to failure, but what about hubs? Are black anodized
    hubs more prone to spoke ripout or other failures?

    -Eric B
     
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  2. > I've heard about anodized rims being more prone to failure, but what about hubs? Are black
    > anodized hubs more prone to spoke ripout or other failures?

    WTF? where did you hear this shit? I've never heard anything like that in my life, and I work at a
    LBS. I've seen plenty of anodized bike componentry, I even run blue anodized Hope Big 'un hubs.
    They're the strongest things I've ever bought for my bike. one year and some insane riding later,
    they're not showing any signs of stressing or cracking round the eyelets. I think you just picked up
    on some urban myth.

    Small Black Dog
     
  3. David Kunz

    David Kunz Guest

    Small Black Dog wrote:
    >>I've heard about anodized rims being more prone to failure, but what about hubs? Are black
    >>anodized hubs more prone to spoke ripout or other failures?
    >
    >
    > WTF? where did you hear this shit? I've never heard anything like that in my life, and I work at a
    > LBS. I've seen plenty of anodized bike componentry, I even run blue anodized Hope Big 'un hubs.
    > They're the strongest things I've ever bought for my bike. one year and some insane riding later,
    > they're not showing any signs of stressing or cracking round the eyelets. I think you just picked
    > up on some urban myth.
    >
    > Small Black Dog
    >

    Gee, you haven't been reading the group (or maybe it's alt.mountain-bike). Many have had problems
    with black anodized rims stress cracking. Do a google search. Check MTBR for black Mavic rims.

    I know that my problems were news to my LBS, but they also told me that I probably ride the most and
    the hardest of their customers. They now hesitate to sell me anything that's light because I just
    break it :).

    David
     
  4. > Gee, you haven't been reading the group (or maybe it's alt.mountain-bike). Many have had problems
    > with black anodized rims stress cracking. Do a google search. Check MTBR for black Mavic rims.
    >
    > I know that my problems were news to my LBS, but they also told me that I probably ride the most
    > and the hardest of their customers. They now hesitate to sell me anything that's light because I
    > just break it :).

    Surely thats just a problem with the quality of the rim, not the anodizing process? I wouldnt have
    thought anodizing something would fck it up so much. I've heard of the lighter, more XC style mavic
    rims being weak at the eyelets. My Dad owns the X517s which I think are one of the problematic
    models. I havent noticed any stressing or cracks ... yet

    Small Black Dog
     
  5. Gregr

    Gregr Guest

    On 18 Apr 2003 23:13:19 -0700, [email protected] (eric bazan) wrote:

    >I've heard about anodized rims being more prone to failure, but what about hubs? Are black anodized
    >hubs more prone to spoke ripout or other failures?

    Its not the black ano that is the major problem, its the hard-ano that is prone to cracking more.
    (the dark murky stuff, mavic calls it CD)

    In my experience, the only rims I have had that developed cracks at the eyeleets were silver ano
    (mavic 238) and a Matrix swami one.

    Have some valiants, mustangs and 223's that so far are crack free.

    G
     
  6. > Its not the black ano that is the major problem, its the hard-ano that is prone to cracking more.
    > (the dark murky stuff, mavic calls it CD)

    The term they like to use is "Ceramic"

    > In my experience, the only rims I have had that developed cracks at the eyeleets were silver ano
    > (mavic 238) and a Matrix swami one.

    The Mavic 238s are about 5 years old, manufacturing has (i hope) improved since then.

    I run Mavic D321 Discs which are the best rims I've used to date. After almost 2 years of riding
    they're still not showing any stresses. My friend bought my old Mavic D521 CDs (with the "Ceramic"
    coating) from me when I upgraded to discs. They've been rolling for even longer, and again, no sign
    of cracks or stressing.

    Small Black Dog
     
  7. Pete Biggs

    Pete Biggs Guest

    Small Black Dog wrote:
    >> I've heard about anodized rims being more prone to failure, but what about hubs? Are black
    >> anodized hubs more prone to spoke ripout or other failures?
    >
    > WTF? where did you hear this shit?

    Read this: http://draco.acs.uci.edu/rbfaq/FAQ/8c.2.html

    Personally, I'm not sure how much of a difference they really make, but one thing I do know for sure
    is that the only rim that I've ever had completely break apart was an MA40: a hard anodized model.

    > I've never heard anything like that in my life, and I work at a LBS.

    No wonder I avoid bike shops. Most know FA.

    ~PB
     
  8. Tim McTeague

    Tim McTeague Guest

    "Small Black Dog" <[email protected]> wrote in message
    news:[email protected]...
    >
    > > Its not the black ano that is the major problem, its the hard-ano that is prone to cracking
    > > more. (the dark murky stuff, mavic calls it CD)
    >
    > The term they like to use is "Ceramic"

    >
    > Small Black Dog

    You work in a bike shop? CD rims are the hard anodized ones. Ceramic rims are CD with a ceramic
    coating on the brake surface. Check out Jobst Brandt's posts via a Google search on hard anodizing
    for details on the cracking issue.

    Tim
     
  9. > No wonder I avoid bike shops. Most know FA.

    Customers know even less :) it all works out in the end.

    Small Black Dog
     
  10. > You work in a bike shop? CD rims are the hard anodized ones. Ceramic
    rims
    > are CD with a ceramic coating on the brake surface. Check out Jobst Brandt's posts via a Google
    > search on hard anodizing for details on the cracking issue.
    >
    > Tim

    Doh. Thats all I can say for not knowing there was infact a difference between the two.

    Small Black Dog
     
  11. Small Black Dog wrote:
    >>I've heard about anodized rims being more prone to failure, but what about hubs? Are black
    >>anodized hubs more prone to spoke ripout or other failures?
    >
    >
    > WTF? where did you hear this shit? I've never heard anything like that in my life, and I work at a
    > LBS. I've seen plenty of anodized bike componentry, I even run blue anodized Hope Big 'un hubs.
    > They're the strongest things I've ever bought for my bike. one year and some insane riding later,
    > they're not showing any signs of stressing or cracking round the eyelets. I think you just picked
    > up on some urban myth.
    >
    > Small Black Dog

    dude, I'd wait a little longer after 4:20 before you post next time ;)

    Jon Bond
     
  12. Pete Biggs

    Pete Biggs Guest

    Small Black Dog wrote:

    >> No wonder I avoid bike shops. Most know FA.
    >
    > Customers know even less :) it all works out in the end.

    Most do, yeah, but not the ones reading this newsgroup :)

    ~PB
     
  13. David Kunz

    David Kunz Guest

    Small Black Dog wrote:
    >>Gee, you haven't been reading the group (or maybe it's alt.mountain-bike). Many have had problems
    >>with black anodized rims stress cracking. Do a google search. Check MTBR for black Mavic rims.
    >>
    >>I know that my problems were news to my LBS, but they also told me that I probably ride the most
    >>and the hardest of their customers. They now hesitate to sell me anything that's light because I
    >>just break it :).
    >
    >
    > Surely thats just a problem with the quality of the rim, not the anodizing process? I wouldnt have
    > thought anodizing something would fck it up so much. I've heard of the lighter, more XC style
    > mavic rims being weak at the eyelets. My Dad owns the X517s which I think are one of the
    > problematic models. I havent noticed any stressing or cracks ... yet
    >
    > Small Black Dog
    >

    Mavic XC rims. x519 -- supposed to be strong. (Also 223, and x219). All black anodized. I don't KNOW
    it's the anodization, but I've been told that it's likely.

    David
     
  14. Jim Beam

    Jim Beam Guest

    i'm new to this group, and i'm amazed at some of the misconceptions about rim cracking. a story gets
    repeated frequently does not make it truthful.

    yes, some cracks can be caused by fatigue, and yes, some fatigue cracks can be caused by cracked
    anodizing. but by far the most common cause of failure is defective extrusions from which the
    rim is made.

    example: http://technology.open.ac.uk/materials/mem/mem-ccf-rims.html

    this is /not/ an anodizing failure.

    nor is this: http://tandem-fahren.de/Mitglieder/Christoph_Timm/imm032a.jpg

    so, to answer your question about hubs, go ahead and enjoy whatever color you want. theoretically,
    they will fatigue eventually, but i seriously doubt you'll /ever/ be able to discern the difference
    between a hub that's clear anodized, and one where the anodizing has been dyed.

    jim

    ps. if you /really/ want to see how fatigue cracks start, read this:
    http://rugth30.phys.rug.nl/msc_micromat/fatigue_crack.htm

    eric bazan wrote:
    > I've heard about anodized rims being more prone to failure, but what about hubs? Are black
    > anodized hubs more prone to spoke ripout or other failures?
    >
    > -Eric B
     
  15. Anodizing is a controlled oxidation of the surface of the aluminum (.001"-.002" for standard,
    .003"-.005" thick for "hard"). It is primarily for scratch resistance (Al O is very scratch
    resistant, same as corundum, ruby or sapphire). But it offers or detract's almost nothing
    structurally, that is just hype to sell components at a higher price.

    The color is a dye added to the anodizing bath. Plain anodizing is clear (silver).

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  16. > >> No wonder I avoid bike shops. Most know FA.
    > >
    > > Customers know even less :) it all works out in the end.
    >
    > Most do, yeah, but not the ones reading this newsgroup :)

    Damn, gonna have to think a bit more before I post then, eh?

    Small Black Dog
     
  17. Jon Isaacs

    Jon Isaacs Guest

    >yes, some cracks can be caused by fatigue, and yes, some fatigue cracks can be caused by cracked
    >anodizing. but by far the most common cause of failure is defective extrusions from which the
    >rim is made.

    I think most of us have had anodized rims fail at the spoke hole, I dont think that an
    extrusion defect.

    Also, the example that is a "rim extrusion defect" looks like a rim with severe brake wear and the
    sidewall was just too thin.

    Jon Isaacs
     
  18. Terry Morse

    Terry Morse Guest

    Mark McMaster wrote:

    > But, it should also be kept in mind that the cracks form from fatigue, and fatigue only occurs in
    > tension.

    That's true for rims (fatigue failure caused by tension), but not for bearings (fatigue failure
    caused by surface compression). Most, but not all, fatigue failure is caused by cyclic tension.
    --
    terry morse Palo Alto, CA http://www.terrymorse.com/bike/
     
  19. Terry Morse wrote:
    > Mark McMaster wrote:
    >
    >
    >>But, it should also be kept in mind that the cracks form from fatigue, and fatigue only occurs in
    >>tension.
    >
    >
    > That's true for rims (fatigue failure caused by tension), but not for bearings (fatigue failure
    > caused by surface compression).

    Are you sure? Contact stresses with rolling elements can produce larger shear stresses under the
    surface of the race. A shear stress has components of both tension and compression.

    Mark McMaster [email protected]
     
  20. Terry Morse

    Terry Morse Guest

    Mark McMaster wrote:

    > Terry Morse wrote:
    > >
    > > That's true for rims (fatigue failure caused by tension), but not for bearings (fatigue failure
    > > caused by surface compression).
    >
    > Are you sure? Contact stresses with rolling elements can produce larger shear stresses under the
    > surface of the race. A shear stress has components of both tension and compression.

    Um, well...okay. A bearing race fatigues from shear (I was thinking more of the external compression
    force than the internal shear stresses).
    --
    terry morse Palo Alto, CA http://www.terrymorse.com/bike/
     
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