Anodizing gone from braking surfaces

Discussion in 'Cycling Equipment' started by Kbh, Apr 28, 2003.

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  1. Kbh

    Kbh Guest

    Have a Sun ME14A rim with about 3000 miles on it, and over the past few hundred (lots of gritty wet
    riding) the anodozing started to disappear and is now almost completely gone from the braking
    surfaces - anything to worry about or is this normal mode of operation?

    Thanks,

    Kyle
     
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  2. In article <[email protected]>, KBH <[email protected]> wrote:
    >Have a Sun ME14A rim with about 3000 miles on it, and over the past few hundred (lots of gritty wet
    >riding) the anodozing started to disappear and is now almost completely gone from the braking
    >surfaces - anything to worry about or is this normal mode of operation?

    Both - it is normal, and eventually you can wear it out. But that usually happens a long while after
    the anodizing is removed. You deal with this via regular inspection for cracks around the nipples
    and on the braking surfaces. The rim will crack when the walls get thin enough. Often you will find
    failure around a spoke hole before you get enough miles on it to wear through the braking surface.
     
  3. Jobst Brandt

    Jobst Brandt Guest

    Paul Southworth writes:

    >> Have a Sun ME14A rim with about 3000 miles on it, and over the past few hundred (lots of gritty
    >> wet riding) the anodizing started to disappear and is now almost completely gone from the braking
    >> surfaces - anything to worry about or is this normal mode of operation?

    > Both - it is normal, and eventually you can wear it out. But that usually happens a long while
    > after the anodizing is removed. You deal with this via regular inspection for cracks around the
    > nipples and on the braking surfaces. The rim will crack when the walls get thin enough. Often you
    > will find failure around a spoke hole before you get enough miles on it to wear through the
    > braking surface.

    Not such a good idea. I have on occasions worn rims to dangerously thin dimensions with no cracking.
    Besides, cracks around nipples has nothing to do with brake surface wear. Find out ho wide the rim
    was when new by measuring one in the store with calipers and then check you rim once in a while. Rim
    walls are a bit over 1.5mm thick. When they get to 0.5 at the thinnest place it is high time to get
    a new rim.

    Jobst Brandt [email protected] Palo Alto CA
     
  4. Yes, it's normal. Your brakes (ALL brakes) work by friction. Friction + wear. Gritty riding, as is
    encountered in MTB'ing, accelerates the process, of course.

    Anodizing is only a controlled oxidation of the surface of the aluminum, which, unlike steel,
    becomes harder when it combines with oxygen, protecting the metal underneath. The greyish coating so
    familiar to old aluminum screen doors is, in fact, a natural anodizing.

    However, this protective coating is only a couple of thousandths of an inch thick (a little thicker
    than the hair on your head) when they were new, so it's not going to last forever. It's just a lot
    more noticeable with "colored" anodizing, which I assume you have.

    Don't worry about it, it won't harm your rims, they're just as strong as when you bought them.
    Again, assuming you have cared for them properly.

    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
     
  5. Mark Hickey

    Mark Hickey Guest

    "KBH" <[email protected]> wrote:

    >Have a Sun ME14A rim with about 3000 miles on it, and over the past few hundred (lots of gritty wet
    >riding) the anodozing started to disappear and is now almost completely gone from the braking
    >surfaces - anything to worry about or is this normal mode of operation?

    I can remember being anxious for the anodizing to wear off my rims so they'd START braking well. The
    worst part was when the anodizing wore off the braking surface at each spoke location first,
    resulting in brake shudder (and a really non-Fabrizio-approved look).

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  6. Matt O'Toole

    Matt O'Toole Guest

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

    > Not such a good idea. I have on occasions worn rims to
    dangerously
    > thin dimensions with no cracking. Besides, cracks around
    nipples has
    > nothing to do with brake surface wear. Find out ho wide
    the rim was
    > when new by measuring one in the store with calipers and
    then check
    > you rim once in a while. Rim walls are a bit over 1.5mm
    thick. When
    > they get to 0.5 at the thinnest place it is high time to
    get a new
    > rim.

    Some newer rims have little wear dimples so you can tell when they've worn too far. I think these
    are required by law now in Europe. Not a bad idea.

    Matt O.
     
  7. Openworld

    Openworld Guest

    Anodised rims use harder brake pads--careful with these pads now the anodising has worn off they
    scrub the walls alot harder. With thin walls make sure you dont jump.-I know its a road bike, but I
    use mine in a similar fashion to cyclocross-failure on landing is quite spectacular.

    "Mark Hickey" <[email protected]> wrote in message
    news:[email protected]...
    > "KBH" <[email protected]> wrote:
    >
    > >Have a Sun ME14A rim with about 3000 miles on it, and over the past few hundred (lots of gritty
    > >wet riding) the anodozing started to disappear
    and
    > >is now almost completely gone from the braking surfaces - anything to
    worry
    > >about or is this normal mode of operation?
    >
    > I can remember being anxious for the anodizing to wear off my rims so they'd START braking well.
    > The worst part was when the anodizing wore off the braking surface at each spoke location first,
    > resulting in brake shudder (and a really non-Fabrizio-approved look).
    >
    > Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  8. Matt O'Toole <[email protected]> wrote:
    >Some newer rims have little wear dimples so you can tell when they've worn too far. I think these
    >are required by law now in Europe. Not a bad idea.

    Certainly not all across Europe.
    --
    David Damerell <[email protected]> Distortion Field!
     
  9. Peter Cole

    Peter Cole Guest

    "Openworld" <[email protected]> wrote in message news:[email protected]...
    > Anodised rims use harder brake pads--careful with these pads now the anodising has worn off they
    > scrub the walls alot harder.

    I think you're describing ceramic-coated (sidewall) rims.
     
  10. Paul Kopit

    Paul Kopit Guest

    On Mon, 28 Apr 2003 18:58:50 -0400 (EDT), [email protected] (Chris Zacho "The Wheelman") wrote:

    >Good idea, Jobst. Now you have to get him a bladed micrometer to measure
    >it. And, of course, instruct him on how to read it, if he doesn't already know ;-3)

    A regular old caliper works fine. You put a ¼" ball bearing in and measure with the caliper and then
    make the adjustment. I bought a plastic caliper at a 99¢ store for 2/$.99.
     
  11. Mark Hickey

    Mark Hickey Guest

    "Peter Cole" <[email protected]> wrote:

    >"Openworld" <[email protected]> wrote in message news:[email protected]...
    >> Anodised rims use harder brake pads--careful with these pads now the anodising has worn off they
    >> scrub the walls alot harder.
    >
    >I think you're describing ceramic-coated (sidewall) rims.

    That was my guess as well. I've certainly never heard about using different brake pads for
    anodized rims.

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
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