Anodizing gone from braking surfaces



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Kbh

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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
 
P

Paul Southworth

Guest
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.
 
J

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
 
C

Chris Zacho "Th

Guest
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
 
M

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
 
M

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.
 
O

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
 
D

David Damerell

Guest
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!
 
P

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.
 
P

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.
 
M

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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