Do aluminum frames wear out?

Quoted message said:

Quoted message said:

Easier to mass produce. Cheaper. Doesn't "dent".

Surely "doesn't dent" is a part of "longevity," isn't it?

My wife rode for years on a Cannondale with big dent in the
top tube before we donated it. Some woman in Team In
Training is probably still using it.

Chris Neary [email hidden]

"Science, freedom, beauty, adventure: what more could you
ask of life? Bicycling combined all the elements I loved" -
Adapted from a quotation by Charles Lindbergh

Peter Cole said:

Quoted message said:

(I do not know the rationale for this, nor the
mechanisms, etc. BUT: Do airframe components "time out"?
There are plenty of commercial aircraft flying after
decades of use. But they are not 6061-T6, I do not
think.)

I wouldn't take any chances, refuse to fly anything but
steel planes!

That Soviet Foxbat that defected to Japan was. We thought it
was titanium like ours, till someone noticed that it was
starting to rust out like an old Chevy. Which proves that if
you put a big enough engine on an anvil, it might fly.
Likewise, if you can pedal hard enough, long enough, it
probably does not matter what something weighs. Growing up,
the neighborhood Rich Kid has one of those Schwinns that had
everything; A generator, lights, an electric horn built into
the tank, tons of chrome. Everyone liked to look at it, and
nobody rode it more than once.

Chris Hansen said:

Hello,

I've talked to two people who have said aluminum frames
wear out. One said that after about 8 years they kind of
go "dead" and lose the feel they once had. Another talked
about how he broke the bottom bracket out of an old
aluminum frame.

Does anyone know anything about this? If you plan to keep
a bike for longer than 10 years is it better not to get
aluminum?

What will you use instead? Steel?

Are your handlebars steel? How about your stem? Your rims?
Your cranks? Your brakes? Your hubs? Your seatpost?

On all my bikes, all those components made of aluminum. On
my favorite bike, the frame is aluminum too. It was made in
1986. Last summer, it took me coast to coast, fully loaded.

The bit about frames "going dead" is absolute nonsense. And
FWIW, most common thinking on aluminum's fatigue life is
nonsense, too.

It's possible to buy a too-light, disposable aluminum frame,
and you may see it fail in a couple years - or a couple
months. But that can happen, and has happened, with steel
frames, titanium frames, carbon fiber frames, magnesium
frames, etc etc.

--
-------------+ Frank Krygowski [To reply, omit what's
between "at" and "cc"]

Cipher said:

Here's something to read on the subject:

ihpva.orgmateriOpen ↗
als.html

Well, it's not too bad.

I probably shouldn't feel this way, but I get skeptical
about the knowledge of anyone who can't spell "Chromium
Mollybenduim" [sic]. Or who gives no hint that it's actually
a type of steel.

--
-------------+ Frank Krygowski [To reply, omit what's
between "at" and "cc"]

Methuselah said:

A vast difference between steel and aluminum was explained
to me by an ME friend thusly: After a million flexural
cycles on a steel structure, it can be considered to have
unlimited life; After a million flexural cycles on an
aluminum structure, it can be considered to have Zero
remaining flexural life.

Your Mechanical Engineer friend was grossly simplifying.
Either that, or you remembered things a bit wrong.

Fatigue life depends on the number of cycles of stress, and
on the level of that stress, as well as the metal
properties. Obviously, some alloys are better than others.

You can certainly flex a steel sample and cause fatigue
failure in far fewer than a million cycles. All you need to
do is provide a high enough stress level. Think of bending a
coat hanger wire back and forth a few dozen times.

What your friend was probably referring to is this: with
steels, it's possible to have an infinite fatigue life, IF
you keep the stress level of each cycle low enough - below
what's called the "endurance limit." IOW, if you bend a
steel part back and forth, but never exceed (say) 10,000
psi, the steel part will _never_ crack due to fatigue.

On the other hand, aluminum alloys do not have an endurance
limit. No matter how low the stress you apply, if you bend
things back and forth enough times, the aluminum part will
fatigue - someday. Eventually.

The question is, when? The lower the stress (just as with
steel) the longer the fatigue will take. Keep the stress
down low enough, and your bike frame may fatigue while your
great-grandchild is riding it in an antique parade, but not
before then.

Quoted message said:

Do airframe components "time out"?

For what it's worth, time has nothing to do with it -
assuming you're not corroding it badly during the
intervening years. It's all based on the number of stress
cycles, and the level of stress in those cycles.

The frame of a bike generally carries fairly low stresses.
It's well triangulated, and most riding is done at low
levels of exertion. I think that, unless you're a Keirin
racer, or you buy a bonded aluminum frame with bad joint
bonds, your aluminum frame will last a long, long time. Mine
certainly has.

--
-------------+ Frank Krygowski [To reply, omit what's
between "at" and "cc"]

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

Quoted message said:

Since aluminum is not as good as steel, riding an
aluminum bike is

dangerous,

Quoted message said:

therefore one should wear a helmet to save one's life!

Woohoooo!

A helmet AND a sweater.

Pete

In article <[email hidden]>,

Benjamin Lewis said:

Peter Cole said:

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

Quoted message said:

Peter Cole wrote:

> It's a mistake to think material has anything to do
> with longevity.
^^^^^^^^ I think you mean "everything".

No, I meant anything.

You're seriously claiming that the material has *nothing*
to do with longevity? So a bicycle made of pasta would
last just as long as a bicycle made of steel, all other
things being equal?

As long as you respected the material, yes. You have to
understand that the tensile strength of pasta being what it
is, you'll need more (by both mass and volume) in order to
make a safe bike.

Also, don't ride in the rain, okay?

Getting back to Fe vs. Al (commercial alloys of them, of
course), Al bikes are "overbuilt" so that it will take a lot
of fatigue cycles (hopefully, more than the lifetime of the
frame, however you care to define that) to degrade it. You
can do this because Al is much, much lighter, giving you a
lot of material to work with.

Steel frames built to a low weight are very economical with
material. You're talking very thin walls and very careful
attention to the amount of metal.

In practice, you can overbuild either Al or Fe frames to
make a very reliable bike. It just doesn't matter which
material you start with from that point of view.

All assertions reasonable or your money back,
--
Ryan Cousineau, [email hidden]
sfu.cawiredcolaOpen ↗ President, Fabrizio
Mazzoleni Fan Club

Ryan Cousineau said:

In article <[email hidden]>, Benjamin

Lewis said:

You're seriously claiming that the material has *nothing*
to do with longevity? So a bicycle made of pasta would
last just as long as a bicycle made of steel, all other
things being equal?

As long as you respected the material, yes. You have to
understand that the tensile strength of pasta being what
it is, you'll need more (by both mass and volume) in order
to make a safe bike.

And once you do that, the longevity of the pasta bike is
magically *exactly the same* as the steel bike? I don't
believe it.

Quoted message said:

Also, don't ride in the rain, okay?

It's okay, my pasta bike has a protective shellac coating.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then
suddenly it flips over, pinning you underneath. At night,
the ice weasels come." --Matt Groening

"Methuselah" <[email hidden]> wrote

Quoted message said:

BUT: Do airframe components "time out"? There are plenty
of commercial aircraft flying after decades of use. But
they are not 6061-T6, I do not think.)

The alloy for the B-52 wing structure, for instance, is T42-
2024. Other assemblies use 7075.

The last 'new' B-52 was deivered in 1962. Boeing has
extended the airframe life out to 2040. Grandsons of some of
the original pilots will be pushing those airframes.

Pete

frkrygow'@omitcc.ysu.edu said:

Cipher said:

Here's something to read on the subject: ihpv-ihpv-Open ↗
a.org/com/PracticalInnovations/materials.html

Well, it's not too bad.

I probably shouldn't feel this way, but I get skeptical
about the knowledge of anyone who can't spell "Chromium
Mollybenduim" [sic]. Or who gives no hint that it's
actually a type of steel.

Heh.

"The major alloys used for making CroMo are Chrome and
Mollybenduim."

Alloys?

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then
suddenly it flips over, pinning you underneath. At night,
the ice weasels come." --Matt Groening

Booker C. Bense said:

Quoted message said:

I've talked to two people who have said aluminum frames
wear out. One said that after about 8 years they kind of
go "dead" and lose the feel they once had. Another talked
about how he broke the bottom bracket out of an old
aluminum frame.

Quoted message said:

Quoted message said:

Does anyone know anything about this? If you plan to keep
a bike for longer than 10 years is it better not to get
aluminum?

Quoted message said:

_ Aluminum alloys will eventually fatigue, whether you'll
use the bike enough for this ever to happen is an open
question.

So why bring it up. Fatigue is an engineering term for crack
development from many stress cycles of sufficient magnitude.
It does not mean the metal (aluminum or steel) gets soft or
dead springiness.

Quoted message said:

_ A high quality steel bike will easily last 30 years. I
ride a 30+ year old steel frame and it's a good as it
ever was.

Fatigue is not measured in years on aluminum, steel or other
structural metal. It is measured in number of stress cycles
at a suitably high load. "Years" implies it is time
dependent. This is not true. Besides, not many people put on
sufficient miles over 30 years to make a frame fail. That
usually occurs much sooner if at all. If the stress level is
high enough to cause a fatigue failure, it will most likely
occur in 10,000 miles (one year of active riding) and not
after 30 years.

Jobst Brandt [email hidden]

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

Mistakes ... (steel)

Quoted message said:

Quoted message said:

Quoted message said:

Easier to mass produce. Cheaper.

... to make (fibreglass)

Quoted message said:

Quoted message said:

Quoted message said:

Doesn't "dent".

Surely "doesn't dent" is a part of "longevity," isn't it?

Not for cars. Hit a fibreglass car with the same force as a
steel car, and you crack the body, rather than leave a dent
that can either be hammered out or just left.

Quoted message said:

My wife rode for years on a Cannondale with big dent in
the top tube

before

Quoted message said:

we donated it. Some woman in Team In Training is probably
still using it.

Car body panels can be left dented for years too. Never seen
a fibreglass car with open holes in it.

Benjamin Lewis said:

Quoted message said:

I probably shouldn't feel this way, but I get skeptical
about the knowledge of anyone who can't spell "Chromium
Mollybenduim" [sic]. Or who gives no hint that it's
actually a type of steel.

Quoted message said:

Heh.

Quoted message said:

"The major alloys used for making CroMo are Chrome and
Mollybenduim."

Quoted message said:

Alloys?

Well, chrome isn't an element so it must be an alloy, and
I'm pretty sure Mollybenduim is someplace in Lord of the
Rings. Probably a cave where dwarfs and gnomes pound bicycle
frames together, with big hammers and a forge.

In article <40629ca1$1@darkstar>,

Benjamin Weiner said:

I'm pretty sure Mollybenduim is someplace in Lord of the
Rings. Probably a cave where dwarfs and gnomes pound
bicycle frames together, with big hammers and a forge.

That's pretty much how I've always pictured CCM. But my
mind's eye has more of a "Fractured Fairy Tales" flavour,
than a Tolkienish one.

cheers, Tom

--
-- Powered by FreeBSD Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca

In article
<[email hidden]>,
[email hidden] says...

Quoted message said:

Hello,

I've talked to two people who have said aluminum frames
wear out. One said that after about 8 years they kind of
go "dead" and lose the feel they once had. Another talked
about how he broke the bottom bracket out of an old
aluminum frame.

Does anyone know anything about this? If you plan to keep
a bike for longer than 10 years is it better not to get
aluminum?

As they usually break within the year, it's hard to say how
they'll feel after 8.
--
Mark Lee

Kevan Smith said:

Since aluminum is not as good as steel, riding an aluminum
bike is dangerous, therefore one should wear a helmet to
save one's life!

Woohoooo!

Don't forget that a mirror is absolutely essential to see
what's behind you at all times!

On Wed, 24 Mar 2004 15:57:44 -0800, Benjamin Lewis <[email hidden]>

Quoted message said:

You're seriously claiming that the material has *nothing*
to do with longevity? So a bicycle made of pasta would last
just as long as a bicycle made of steel, all other things
being equal?

This is bogus. Virtually all conversations, even on Usenet,
recognize that there is a relevant range. We're not talking
about pasta because most of us aren't sophomoric debaters.
We're talking about the relevant range, which would include
the common materials used in bicycle frame construction.

I've seen bamboo frames and rims, but I think we're
basically talking about steel, aluminum/aluminium and carbon
fiber or whatever the material is technically. I think we
can leave out bamboo (although it does make good rims),
pasta and PVC, among others. Or do we need to list all
materials that we do include and all that we do not to make
you happy?

Curtis L. Russell Odenton, MD (USA) Just someone on
two wheels...

Curtis L. Russell said:

I've seen bamboo frames and rims, but I think we're
basically talking about steel, aluminum/aluminium and
carbon fiber or whatever the material is technically.

Guess I forgot Titanium. But I'm still leaving out pasta.

Curtis L. Russell <[email hidden]> wrote in
message [email hidden]

Quoted message said:

On Thu, 25 Mar 2004 08:40:14 -0500, Curtis L. Russell <curtis@the-md-

russells.org said:

I've seen bamboo frames and rims, but I think we're
basically talking about steel, aluminum/aluminium and
carbon fiber or whatever the material is technically.

Guess I forgot Titanium. But I'm still leaving out pasta.

Even if it's al dente?

--

"I'm proud that I live in a country where witnessing two
hours of bloody, barbarous torture in gloating detail is
considered indicia of religious piety, whereas a mere second
gazing upon a woman's breast is cause for outraged
apoplexy." Betty Bowers,
bettybowers.commelgibsonpassion.htmlOpen ↗

Well, I don't think so.

Aluminum will fatigue given enough cycles of stress. Steel
does not fatigue if the stress is below a certain threshold.
This has been discussed in a previous post.

Now, I had an old Cannondale Black Lightning years ago. It
was a great bike. It transmitted all the road shock
imaginable but it cornered great and accelerated like a
scalded cat. Eventually, it got retired because of
obsolescent components more then anything else. But it
remains my favorite bike. I put something over 50,000 miles
on it and I weigh 200 lbs and I rode reasonably fast then. I
never noticed any decline in handling over time but
something that happens gradually is hard to notice.

Well I had that bike as a loaner if a friend visited and
needed a ride. Everyone who rode this bike LOVED it and that
was after 50,000 miles a use. They especially commented on
its stiffness, acceleration and handling. They even said it
was superior in those respects to their current rides. As I
recall, people did mention the harsh ride but who cares when
you are riding a rocket? So if it had gone soft, it must
have been really something brand new.

So will the frame wear out? Sure given enough use, it will
wear out. Anything will wear out given enough use. I just
don't know that there is good evidence that of bike frames
wearing out in actual practice.