Alu MTB Frame life limited?

[Mike Jacoubowsk]

> success". They concluded that there is no 100% way to join aluminum.
Done in the
> best environment and procedures it can only come to 98 percent, which in
my mind
> means 2 out of every 100 bicycle frames will fail.

Taking your information about failure literally, it wouldn't be 2 out of 100 frames failing, but
close to one out of five, since a frame represent not just one point of weld failure, but up to 20.

I'm guessing that it means 2 out of every 100 bicycle frames won't be optimally welded (not that 2
out of every 100 will fail). Very few designs are so close to the edge that they demand absolute
perfection in order to work. The typical aluminum bicycle frame is overbuilt and not dependent upon
a 100% perfect joint.

> Titanium, on the other hand is certainly the toughest. It kills the
cutting tools
> quick, and is hard to bend. Properties that seem nice to have on a
bicycle.

This seems a bit contradictory. If Titanium is the toughest to build properly, why isn't this a
concern for a bicycle? When you talk about 100% reliability in NASA applications, my guess is that
that's dependent upon x-raying the welds. Sorry, but this isn't done in the bicycle industry.
Instead, you're dependent upon someone taking all the necessary (and tough, as you say) steps to do
it the right way, with a whole lot of things that can go wrong along the way. But in the end, it
really doesn't matter because Ti bikes, just like Aluminum ones, are also built with a reasonable
margin of safety, such that minor imperfections aren't going to cause failure.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

"S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
news:[email protected]...
> Pete Before taking up bicycles full time I worked for NASA as a tech. My
primary role
> was as a T.I.G. welder but was also certified for bonding (glue) and
riveting.
> We made high tech parts from all materials. NASA rates all structures and for that matter all
> projects by a
"percentage of
> success". They concluded that there is no 100% way to join aluminum.
Done in the
> best environment and procedures it can only come to 98 percent, which in
my mind
> means 2 out of every 100 bicycle frames will fail. Aircraft are REQUIRED to have routine
> inspections and are repaired
routinely. How
> many bike riders routinely inspect their bikes for cracks? Passenger aircraft usually are rated
> for 20 years service. Fatigue life for aluminum is known to be shorter than other common
materials.
> Steel and titanium can be joined to 100% reliability. Done properly. Joining composite structures
> is also problematic and not able to achieve
100%
> success. Aluminum is cheap, abundant, light and easy to form, weld, and bend,
important in
> keeping the cost down for mass production. Titanium, on the other hand is certainly the toughest.
> It kills the
cutting tools
> quick, and is hard to bend. Properties that seem nice to have on a
bicycle.
> Steve "Speedy" Delaire
>
>
> "(Pete Cresswell)" wrote:
>
> > Just saw a post on alt.mountain-bike ("Foes Customer Service - someone
else
> > doin' it right") that contained the statement:
> >
> > "Believe it or not, if ridden off-road for that long (minimum it seems 5 years) just about any
> > aluminum frame will break."
> >
> > I've heard others say that this is nonsense, but source seems pretty
reliable.
> >
> > OTOH, airplane frames last a lot longer than 5 years...
> >
> > Comments?
> > -----------------------
> > Pete Cresswell
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

[S. Delaire \"Ro]

Mike Some flaws in your thinking here. The success rate is based on a complete structure not
individual welds. Most all welded aluminum failures happen NEXT to the weld not IN the weld due to
the microscopic change in the parent material from the welding process. This means the failure has
nothing to do with the craftsmanship of the welder but has everything to do with the nature of the
material. In the aircraft industry chrome/moly steel is required to be heat treated after welding
yet no one in the bicycle industry post treats a steel frame even though the tensile strength could
be improved by almost 100% Another example of market forces at work. If a long lasting frame is
desired titanium makes sense because it is so tough. The titanium alloys being used for bike frames
do not require post treatment. During the welding process there are some obvious visual clues if the
weld is right or not. At the microscopic level the parent material is not affected the same as
aluminum. Titanium frame failures do happen but most often start IN the weld. A craftsmanship
problem not a material problem. Part of the NASA welding certification process was to do samples
that were dissected in every possible way, tensile (pull) test, bend, X ray, dye penetrant,
microscopic. The deficiencies in properly welded aluminum were easy to see. Again I say aluminum is
a cheap abundant material that is easy to mass produce but is not the most reliable. Just the facts
Steve "Speedy" Delaire

Mike Jacoubowsky wrote:

> > success". They concluded that there is no 100% way to join aluminum.
> Done in the
> > best environment and procedures it can only come to 98 percent, which in
> my mind
> > means 2 out of every 100 bicycle frames will fail.
>
> Taking your information about failure literally, it wouldn't be 2 out of 100 frames failing,
> but close to one out of five, since a frame represent not just one point of weld failure, but
> up to 20.
>
> I'm guessing that it means 2 out of every 100 bicycle frames won't be optimally welded (not that 2
> out of every 100 will fail). Very few designs are so close to the edge that they demand absolute
> perfection in order to work. The typical aluminum bicycle frame is overbuilt and not dependent
> upon a 100% perfect joint.
>
> > Titanium, on the other hand is certainly the toughest. It kills the
> cutting tools
> > quick, and is hard to bend. Properties that seem nice to have on a
> bicycle.
>
> This seems a bit contradictory. If Titanium is the toughest to build properly, why isn't this a
> concern for a bicycle? When you talk about 100% reliability in NASA applications, my guess is that
> that's dependent upon x-raying the welds. Sorry, but this isn't done in the bicycle industry.
> Instead, you're dependent upon someone taking all the necessary (and tough, as you say) steps to
> do it the right way, with a whole lot of things that can go wrong along the way. But in the end,
> it really doesn't matter because Ti bikes, just like Aluminum ones, are also built with a
> reasonable margin of safety, such that minor imperfections aren't going to cause failure.
>
> --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
>
> "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> news:[email protected]...
> > Pete Before taking up bicycles full time I worked for NASA as a tech. My
> primary role
> > was as a T.I.G. welder but was also certified for bonding (glue) and
> riveting.
> > We made high tech parts from all materials. NASA rates all structures and for that matter all
> > projects by a
> "percentage of
> > success". They concluded that there is no 100% way to join aluminum.
> Done in the
> > best environment and procedures it can only come to 98 percent, which in
> my mind
> > means 2 out of every 100 bicycle frames will fail. Aircraft are REQUIRED to have routine
> > inspections and are repaired
> routinely. How
> > many bike riders routinely inspect their bikes for cracks? Passenger aircraft usually are rated
> > for 20 years service. Fatigue life for aluminum is known to be shorter than other common
> materials.
> > Steel and titanium can be joined to 100% reliability. Done properly. Joining composite
> > structures is also problematic and not able to achieve
> 100%
> > success. Aluminum is cheap, abundant, light and easy to form, weld, and bend,
> important in
> > keeping the cost down for mass production. Titanium, on the other hand is certainly the
> > toughest. It kills the
> cutting tools
> > quick, and is hard to bend. Properties that seem nice to have on a
> bicycle.
> > Steve "Speedy" Delaire
> >
> >
> > "(Pete Cresswell)" wrote:
> >
> > > Just saw a post on alt.mountain-bike ("Foes Customer Service - someone
> else
> > > doin' it right") that contained the statement:
> > >
> > > "Believe it or not, if ridden off-road for that long (minimum it seems 5 years) just about any
> > > aluminum frame will break."
> > >
> > > I've heard others say that this is nonsense, but source seems pretty
> reliable.
> > >
> > > OTOH, airplane frames last a lot longer than 5 years...
> > >
> > > Comments?
> > > -----------------------
> > > Pete Cresswell
> >
> >
> >
> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> > Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

[Jon Isaacs]

>They concluded that there is no 100% way to join aluminum. Done in the best environment and
>procedures it can only come to 98 percent, which in my mind means 2 out of every 100 bicycle frames
>will fail.

I don't believe it means that at all. It just means the joint has to be properly designed so that it
does not fail.

>Fatigue life for aluminum is known to be shorter than other common materials.

Have you looked at the S/N curves for aluminum? The fatigue life is dependent upon the design so one
cannot say that aluminum has a shorter fatigue life unless the exact conditions are known. Fatigue
failure is a design issue with nearly all materials. Steel and Ti may fail first if the frames are
of equal weight. This is certainly what happened in the famous German frame fatigue test.

>Titanium, on the other hand is certainly the toughest. It kills the cutting tools quick, and is
>hard to bend. Properties that seem nice to have on a bicycle.

And plenty of Ti bikes suffer fatigue failure, not at all uncommon. In fact there is a current
thread which has some interesting photos of a LiteSpeed MTB that failed.

Design and fabrication are the two most important factors in durable and reliable frames. Titanium
apparently is tough to weld properly and more sensitive to contamination etc than aluminum or steel.

jon isaacs

Jon Isaacs

 

[Mike Jacoubowsk]

> Some flaws in your thinking here. The success rate is based on a complete structure not
> individual welds.

Uh, no, that was the flaw in your original post, not mine. You made the claim that a 98% success
rate of weld or process or whatever was the case with aluminum, without making any reference
whatsoever to a complete structure... you simply extrapolated it out to mean that a bicycle met the
criteria. My point was that a bicycle has "x" degree of welds and complexity; what is that 98%
figure based upon? Did NASA actually come up with a BLO (Bicycle-like-object) that they based their
research on? I doubt
it.

Could it be that NASA determined a 98% joint success rate based upon an entire spacecraft
(including booster rockets)? Who knows. That's exactly the point though. We don't know what the
info is based upon.

> In the aircraft industry chrome/moly steel is required to be heat treated
after
> welding yet no one in the bicycle industry post treats a steel frame even
though
> the tensile strength could be improved by almost 100% Another example of
market
> forces at work.

This is something for others (with a better background in such things) to comment on. However, is
100% improved tensile strength in steel really a relevant factor, given what the tensile strength is
in a finished product built from 853? I suspect tensile strength isn't a limiting factor in building
a strong, lightweight steel frame, regardless of cost.

Those same "market forces at work" are every bit as likely to reward the fool with a lot of money,
who is willing to pay huge $$$ for a benefit that's not actually relevant to how a bicycle
performs or its durability. "Market forces" don't simply work to bring an item down to its
lowest-possible cost.

> The titanium alloys being used for bike frames do not require post
treatment.
> During the welding process there are some obvious visual clues if the weld
is
> right or not.

Right. So we're back to square one, where we're totally dependent upon the skill of the person
building the product to do it correctly.

> Again I say aluminum is a cheap abundant material that is easy to mass
produce
> but is not the most reliable.

It all depends upon the criteria. If you had, say, $300 to invest in an aluminum or titanium frame,
would you still maintain the aluminum frame would be less reliable? If money wasn't an issue and you
wanted a 2.6lb frame, do you still think aluminum would be the most reliable (given titanium's
record of durability is markedly different below 3lbs vs above)?

Any material, brought to the edge of what's possible in terms of fabrication, is going to have
problems. This is very common in ultra-light Ti frames, just as it is in stupid-light (that's one
category below ultra-light) aluminum frames. At some point you're pushing the material a bit too far
and the realities of the real world intrude in ugly ways (when everything's not exactly perfect).

This isn't about mass production, but rather about using a material to its best advantage. A
properly-built Ti frame is a work of art and should last forever, as should a properly-built
aluminum, carbon or steel frame. It's not the material that makes the difference. Nor is it about
a 98% joint success rate (which really needs to be defined before it's tossed around any
further). It's the overall durability of the finished structure that counts. Or, simply, how the
material is used.

--Mike-- Chain Reaction Bicycles http://www.ChainReaction.com

"S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
news:[email protected]...
> Mike Some flaws in your thinking here. The success rate is based on a complete structure not
> individual welds. Most all welded aluminum failures happen NEXT to the
weld
> not IN the weld due to the microscopic change in the parent material from
the
> welding process. This means the failure has nothing to do with the
craftsmanship
> of the welder but has everything to do with the nature of the material. In the aircraft industry
> chrome/moly steel is required to be heat treated
after
> welding yet no one in the bicycle industry post treats a steel frame even
though
> the tensile strength could be improved by almost 100% Another example of
market
> forces at work. If a long lasting frame is desired titanium makes sense because it is so
tough.
> The titanium alloys being used for bike frames do not require post
treatment.
> During the welding process there are some obvious visual clues if the weld
is
> right or not. At the microscopic level the parent material is not affected
the
> same as aluminum. Titanium frame failures do happen but most often start
IN the
> weld. A craftsmanship problem not a material problem. Part of the NASA welding certification
> process was to do samples that were dissected in every possible way, tensile (pull) test, bend, X
> ray, dye penetrant, microscopic. The deficiencies in properly welded aluminum were
easy
> to see. Again I say aluminum is a cheap abundant material that is easy to mass
produce
> but is not the most reliable. Just the facts Steve "Speedy" Delaire
>
>
>
> Mike Jacoubowsky wrote:
>
> > > success". They concluded that there is no 100% way to join aluminum.
> > Done in the
> > > best environment and procedures it can only come to 98 percent, which
in
> > my mind
> > > means 2 out of every 100 bicycle frames will fail.
> >
> > Taking your information about failure literally, it wouldn't be 2 out of
100
> > frames failing, but close to one out of five, since a frame represent
not
> > just one point of weld failure, but up to 20.
> >
> > I'm guessing that it means 2 out of every 100 bicycle frames won't be optimally welded (not that
> > 2 out of every 100 will fail). Very few
designs
> > are so close to the edge that they demand absolute perfection in order
to
> > work. The typical aluminum bicycle frame is overbuilt and not dependent upon a 100% perfect
> > joint.
> >
> > > Titanium, on the other hand is certainly the toughest. It kills the
> > cutting tools
> > > quick, and is hard to bend. Properties that seem nice to have on a
> > bicycle.
> >
> > This seems a bit contradictory. If Titanium is the toughest to build properly, why isn't this a
> > concern for a bicycle? When you talk about
100%
> > reliability in NASA applications, my guess is that that's dependent upon x-raying the welds.
> > Sorry, but this isn't done in the bicycle industry. Instead, you're dependent upon someone
> > taking all the necessary (and
tough,
> > as you say) steps to do it the right way, with a whole lot of things
that
> > can go wrong along the way. But in the end, it really doesn't matter because Ti bikes, just like
> > Aluminum ones, are also built with a
reasonable
> > margin of safety, such that minor imperfections aren't going to cause failure.
> >
> > --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
> >
> > "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> > news:[email protected]...
> > > Pete Before taking up bicycles full time I worked for NASA as a tech. My
> > primary role
> > > was as a T.I.G. welder but was also certified for bonding (glue) and
> > riveting.
> > > We made high tech parts from all materials. NASA rates all structures and for that matter all
> > > projects by a
> > "percentage of
> > > success". They concluded that there is no 100% way to join aluminum.
> > Done in the
> > > best environment and procedures it can only come to 98 percent, which
in
> > my mind
> > > means 2 out of every 100 bicycle frames will fail. Aircraft are REQUIRED to have routine
> > > inspections and are repaired
> > routinely. How
> > > many bike riders routinely inspect their bikes for cracks? Passenger aircraft usually are
> > > rated for 20 years service. Fatigue life for aluminum is known to be shorter than other common
> > materials.
> > > Steel and titanium can be joined to 100% reliability. Done properly. Joining composite
> > > structures is also problematic and not able to
achieve
> > 100%
> > > success. Aluminum is cheap, abundant, light and easy to form, weld, and bend,
> > important in
> > > keeping the cost down for mass production. Titanium, on the other hand is certainly the
> > > toughest. It kills the
> > cutting tools
> > > quick, and is hard to bend. Properties that seem nice to have on a
> > bicycle.
> > > Steve "Speedy" Delaire
> > >
> > >
> > > "(Pete Cresswell)" wrote:
> > >
> > > > Just saw a post on alt.mountain-bike ("Foes Customer Service -
someone
> > else
> > > > doin' it right") that contained the statement:
> > > >
> > > > "Believe it or not, if ridden off-road for that long (minimum it
seems 5
> > > > years) just about any aluminum frame will break."
> > > >
> > > > I've heard others say that this is nonsense, but source seems pretty
> > reliable.
> > > >
> > > > OTOH, airplane frames last a lot longer than 5 years...
> > > >
> > > > Comments?
> > > > -----------------------
> > > > Pete Cresswell
> > >
> > >
> > >
> > > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The
> > > #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers!
> > > =-----
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

[Jim Edgar]

Mike Jacoubowsky at [email protected] responded to a prior post on 1/20/03
5:57 PM:
>> Again I say aluminum is a cheap abundant material that is easy to mass produce but is not the
>> most reliable.
>
> It all depends upon the criteria. If you had, say, $300 to invest in an aluminum or titanium
> frame, would you still maintain the aluminum frame would be less reliable? If money wasn't an
> issue and you wanted a 2.6lb frame, do you still think aluminum would be the most reliable (given
> titanium's record of durability is markedly different below 3lbs vs above)?
>
> Any material, brought to the edge of what's possible in terms of fabrication, is going to have
> problems. This is very common in ultra-light Ti frames, just as it is in stupid-light (that's one
> category below ultra-light) aluminum frames. At some point you're pushing the material a bit too
> far and the realities of the real world intrude in ugly ways (when everything's not exactly
> perfect).
>
> This isn't about mass production, but rather about using a material to its best advantage. A
> properly-built Ti frame is a work of art and should last forever, as should a properly-built
> aluminum, carbon or steel frame. It's not the material that makes the difference. Nor is it about
> a 98% joint success rate (which really needs to be defined before it's tossed around any
> further). It's the overall durability of the finished structure that counts. Or, simply, how the
> material is used.

Well put, Mike. The only thing I would add is that aluminum does have, "finite cycles to
fatigue". My understanding of this is that even a low force, repeated enough times, will cause
the material to yield.

This could point us back toward design issues, _in_ _addition_ to material issues. If frames are
failing on the edge of the weld, (and the bulk of the aluminim frames I've seen would support that)
that would suggest that the stress risers caused by the placement of the weld joint (and directed by
any gusseting, etc.), are the cause of the failure. (Ignoring ham-fisted, monday-morning, hungover
weld work that overheats the entire area...)

Would this would occur more quickly and in a more dramatic fashion on an aluminim frame than steel
or titanium...? I tend to think so, given the way that aluminum tends to fail - with less apparent
warning than steel certainly...

So far, the only frame I've had fail was a high-end aluminum MTB frame, which failed next to a weld
on the chainstay, about 5 months before the warranty ran out. (Whew!)

-- Jim (ridin' steel, aluminum and carbon...)

 

[Ajames54]

On Tue, 21 Jan 2003 01:57:30 GMT, "Mike Jacoubowsky" <[email protected]> wrote:

>> Some flaws in your thinking here. The success rate is based on a complete structure not
>> individual welds.
>
>Uh, no, that was the flaw in your original post, not mine. You made the claim that a 98% success
>rate of weld or process or whatever was the case with aluminum, without making any reference
>whatsoever to a complete structure... you simply extrapolated it out to mean that a bicycle met the
>criteria. My point was that a bicycle has "x" degree of welds and complexity; what is that 98%
>figure based upon? Did NASA actually come up with a BLO (Bicycle-like-object) that they based their
>research on? I doubt
>it.
>
>Could it be that NASA determined a 98% joint success rate based upon an entire spacecraft
>(including booster rockets)? Who knows. That's exactly the point though. We don't know what the
>info is based upon.
>

I'm going to stick my nose back in this thread, mostly because when I left the Bike business I went
to aerospace (kinda like those two guys from Ohio) I was the supervisor of quality assurance for a
small firm with some big clients ... anyway (based on our firm)... when they talk about 98% success
(I can't believe it is that low) that is simply that amount of acceptable defective (scrap) material
from production process. There is a very strict testing regimen in place to ensure that none of
these parts ever make it into the finished product. To simply say that one in 50 parts will
inevitably fail is misleading (and I'm pretty sure that is not what you said ... I just don't want
anyone to misunderstand).

Anyway ... back on topic, every material or process has its own particular production problems.
Those things that are a concern with a lugged and silver-soldered Reynolds 531 frame are different
than a tig-welded Tange Prestiege ... or a Tig -welded Aluminum or Ti frame ... not to mention CF.

If the design / engineering people do their jobs correctly there is nothing in the choice of those
materials that in and of itself places a life span limit on a bike made from it. The thread started
out by asking if "any" (read every) Alum bike has a finite life, and that is not true, I've got an
'88 Vitus road frame that I love and still ride with no worries, If I had a '90 Klien I would still
have no worries about it either. The issue came up because market forces have decided that the
weight weenies rule... and we now have "stupid-lite" and rider weight limits and warranties that
last only three to five years ...

And what company is going to argue ... if they can, in time convince everyone that a 3 year
warrantee is normal it will save them lots of money.

Every time I see one of these threads I get the desire to spec out the sub 1 lb MTB frame ... call
it the Caveat-Emptor .. made from an Epoxy Cellulose (1) material as referenced in a number of
MIL / ANSI / NAS etc specs (2) Guaranteed to last 25 years as long as it is never ridden by anyone
over 250 poundals (3).

(1) Paper / paper mache
(2) They all have very official sounding specs covering the cardboard boxes and packaging paper used
to ship parts.
(3) 250 poundals = approx. 7.7 pounds

Oh ....! Snuh?

 

[S. Delaire \"Ro]

Mike Perhaps I should have started by saying that I have had enough broken aluminum frames that I
will never trust my life to another ever again. Is you look at the molecular structure of aluminum,
steel, and titanium they are very different. Aluminum at the microscopic level looks like balls
individually packed together. It has no significant interlocking grain structure. Pure aluminum has
such low strength as to be useless and needs to be alloyed with other materials for it to be
engineered to bicycle applications. Copper is a common alloy ingredient. Problem is that when
welding, copper tends to "run away" from the heat source. Under the microscope it looks similar to
what happens to a nylon rope when a match is put to it. The welding rod will have higher levers of
copper to try and offset this problem and post heat treatment is also used to help "straighten" the
copper back into place. In practice not all the copper straightens out so right next to the weld
there will be a small but significant gap of aluminum with the incorrect amount or none of the
alloying materials. Note... not all grades of aluminum are considered "weld able" Pure iron is also
useless for bicycles. Alloyed it becomes steel. Steel at the microscopic level looks a lot like wood
with long strands of fiber interlocked together all headed in the same direction. Steel has more
welding options such as silver brazing, fillet brazing, MIG welding, TIG welding. When looking at
the high strength alloys as used in bicycles, if, during the welding process the parent material
becomes "molten" then a post treatment will increase strength and the service life. For some reason
no one post treats steel bicycle frames. Why? Market forces? With titanium, the more pure it is the
higher the strength. Add some alloys it becomes stronger still. Under the microscope the molecule
looks like a snow flake with velcro. The molecules interlock in all directions. Welding doesn't
disturb the matrix like other materials. Ride or sell aluminum if you like. For me the risk is too
high. Steve "Speedy" Delaire

Mike Jacoubowsky wrote:

> > Some flaws in your thinking here. The success rate is based on a complete structure not
> > individual welds.
>
> Uh, no, that was the flaw in your original post, not mine. You made the claim that a 98% success
> rate of weld or process or whatever was the case with aluminum, without making any reference
> whatsoever to a complete structure... you simply extrapolated it out to mean that a bicycle met
> the criteria. My point was that a bicycle has "x" degree of welds and complexity; what is that 98%
> figure based upon? Did NASA actually come up with a BLO (Bicycle-like-object) that they based
> their research on? I doubt
> it.
>
> Could it be that NASA determined a 98% joint success rate based upon an entire spacecraft
> (including booster rockets)? Who knows. That's exactly the point though. We don't know what the
> info is based upon.
>
> > In the aircraft industry chrome/moly steel is required to be heat treated
> after
> > welding yet no one in the bicycle industry post treats a steel frame even
> though
> > the tensile strength could be improved by almost 100% Another example of
> market
> > forces at work.
>
> This is something for others (with a better background in such things) to comment on. However, is
> 100% improved tensile strength in steel really a relevant factor, given what the tensile strength
> is in a finished product built from 853? I suspect tensile strength isn't a limiting factor in
> building a strong, lightweight steel frame, regardless of cost.
>
> Those same "market forces at work" are every bit as likely to reward the fool with a lot of money,
> who is willing to pay huge $$$ for a benefit that's not actually relevant to how a bicycle
> performs or its durability. "Market forces" don't simply work to bring an item down to its
> lowest-possible cost.
>
> > The titanium alloys being used for bike frames do not require post
> treatment.
> > During the welding process there are some obvious visual clues if the weld
> is
> > right or not.
>
> Right. So we're back to square one, where we're totally dependent upon the skill of the person
> building the product to do it correctly.
>
> > Again I say aluminum is a cheap abundant material that is easy to mass
> produce
> > but is not the most reliable.
>
> It all depends upon the criteria. If you had, say, $300 to invest in an aluminum or titanium
> frame, would you still maintain the aluminum frame would be less reliable? If money wasn't an
> issue and you wanted a 2.6lb frame, do you still think aluminum would be the most reliable (given
> titanium's record of durability is markedly different below 3lbs vs above)?
>
> Any material, brought to the edge of what's possible in terms of fabrication, is going to have
> problems. This is very common in ultra-light Ti frames, just as it is in stupid-light (that's one
> category below ultra-light) aluminum frames. At some point you're pushing the material a bit too
> far and the realities of the real world intrude in ugly ways (when everything's not exactly
> perfect).
>
> This isn't about mass production, but rather about using a material to its best advantage. A
> properly-built Ti frame is a work of art and should last forever, as should a properly-built
> aluminum, carbon or steel frame. It's not the material that makes the difference. Nor is it about
> a 98% joint success rate (which really needs to be defined before it's tossed around any
> further). It's the overall durability of the finished structure that counts. Or, simply, how the
> material is used.
>
> --Mike-- Chain Reaction Bicycles http://www.ChainReaction.com
>
> "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> news:[email protected]...
> > Mike Some flaws in your thinking here. The success rate is based on a complete structure not
> > individual welds. Most all welded aluminum failures happen NEXT to the
> weld
> > not IN the weld due to the microscopic change in the parent material from
> the
> > welding process. This means the failure has nothing to do with the
> craftsmanship
> > of the welder but has everything to do with the nature of the material. In the aircraft industry
> > chrome/moly steel is required to be heat treated
> after
> > welding yet no one in the bicycle industry post treats a steel frame even
> though
> > the tensile strength could be improved by almost 100% Another example of
> market
> > forces at work. If a long lasting frame is desired titanium makes sense because it is so
> tough.
> > The titanium alloys being used for bike frames do not require post
> treatment.
> > During the welding process there are some obvious visual clues if the weld
> is
> > right or not. At the microscopic level the parent material is not affected
> the
> > same as aluminum. Titanium frame failures do happen but most often start
> IN the
> > weld. A craftsmanship problem not a material problem. Part of the NASA welding certification
> > process was to do samples that were dissected in every possible way, tensile (pull) test, bend,
> > X ray, dye penetrant, microscopic. The deficiencies in properly welded aluminum were
> easy
> > to see. Again I say aluminum is a cheap abundant material that is easy to mass
> produce
> > but is not the most reliable. Just the facts Steve "Speedy" Delaire
> >
> >
> >
> > Mike Jacoubowsky wrote:
> >
> > > > success". They concluded that there is no 100% way to join aluminum.
> > > Done in the
> > > > best environment and procedures it can only come to 98 percent, which
> in
> > > my mind
> > > > means 2 out of every 100 bicycle frames will fail.
> > >
> > > Taking your information about failure literally, it wouldn't be 2 out of
> 100
> > > frames failing, but close to one out of five, since a frame represent
> not
> > > just one point of weld failure, but up to 20.
> > >
> > > I'm guessing that it means 2 out of every 100 bicycle frames won't be optimally welded (not
> > > that 2 out of every 100 will fail). Very few
> designs
> > > are so close to the edge that they demand absolute perfection in order
> to
> > > work. The typical aluminum bicycle frame is overbuilt and not dependent upon a 100% perfect
> > > joint.
> > >
> > > > Titanium, on the other hand is certainly the toughest. It kills the
> > > cutting tools
> > > > quick, and is hard to bend. Properties that seem nice to have on a
> > > bicycle.
> > >
> > > This seems a bit contradictory. If Titanium is the toughest to build properly, why isn't this
> > > a concern for a bicycle? When you talk about
> 100%
> > > reliability in NASA applications, my guess is that that's dependent upon x-raying the welds.
> > > Sorry, but this isn't done in the bicycle industry. Instead, you're dependent upon someone
> > > taking all the necessary (and
> tough,
> > > as you say) steps to do it the right way, with a whole lot of things
> that
> > > can go wrong along the way. But in the end, it really doesn't matter because Ti bikes, just
> > > like Aluminum ones, are also built with a
> reasonable
> > > margin of safety, such that minor imperfections aren't going to cause failure.
> > >
> > > --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
> > >
> > > "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > Pete Before taking up bicycles full time I worked for NASA as a tech. My
> > > primary role
> > > > was as a T.I.G. welder but was also certified for bonding (glue) and
> > > riveting.
> > > > We made high tech parts from all materials. NASA rates all structures and for that matter
> > > > all projects by a
> > > "percentage of
> > > > success". They concluded that there is no 100% way to join aluminum.
> > > Done in the
> > > > best environment and procedures it can only come to 98 percent, which
> in
> > > my mind
> > > > means 2 out of every 100 bicycle frames will fail. Aircraft are REQUIRED to have routine
> > > > inspections and are repaired
> > > routinely. How
> > > > many bike riders routinely inspect their bikes for cracks? Passenger aircraft usually are
> > > > rated for 20 years service. Fatigue life for aluminum is known to be shorter than other
> > > > common
> > > materials.
> > > > Steel and titanium can be joined to 100% reliability. Done properly. Joining composite
> > > > structures is also problematic and not able to
> achieve
> > > 100%
> > > > success. Aluminum is cheap, abundant, light and easy to form, weld, and bend,
> > > important in
> > > > keeping the cost down for mass production. Titanium, on the other hand is certainly the
> > > > toughest. It kills the
> > > cutting tools
> > > > quick, and is hard to bend. Properties that seem nice to have on a
> > > bicycle.
> > > > Steve "Speedy" Delaire
> > > >
> > > >
> > > > "(Pete Cresswell)" wrote:
> > > >
> > > > > Just saw a post on alt.mountain-bike ("Foes Customer Service -
> someone
> > > else
> > > > > doin' it right") that contained the statement:
> > > > >
> > > > > "Believe it or not, if ridden off-road for that long (minimum it
> seems 5
> > > > > years) just about any aluminum frame will break."
> > > > >
> > > > > I've heard others say that this is nonsense, but source seems pretty
> > > reliable.
> > > > >
> > > > > OTOH, airplane frames last a lot longer than 5 years...
> > > > >
> > > > > Comments?
> > > > > -----------------------
> > > > > Pete Cresswell
> > > >
> > > >
> > > >
> > > > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com -
> > > > The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different
> > > > Servers! =-----
> >
> >
> >
> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> > Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

[A Muzi]

-snip a long thread- "S. Delaire "Rotatorrecumbent"" <[email protected]> top-posted in message
news:[email protected]...
> Mike Perhaps I should have started by saying that I have had enough broken
aluminum
> frames that I will never trust my life to another ever again. Is you look at the molecular
> structure of aluminum, steel, and titanium
they are
> very different. Aluminum at the microscopic level looks like balls individually packed
together.
> It has no significant interlocking grain structure. Pure aluminum has such
low
> strength as to be useless and needs to be alloyed with other materials for
it to
> be engineered to bicycle applications. Copper is a common alloy
ingredient.
> Problem is that when welding, copper tends to "run away" from the heat
source.
> Under the microscope it looks similar to what happens to a nylon rope when
a
> match is put to it. The welding rod will have higher levers of copper to
try and
> offset this problem and post heat treatment is also used to help
"straighten"
> the copper back into place. In practice not all the copper straightens out
so
> right next to the weld there will be a small but significant gap of
aluminum
> with the incorrect amount or none of the alloying materials. Note... not
all
> grades of aluminum are considered "weld able" Pure iron is also useless for bicycles. Alloyed it
> becomes steel. Steel at the microscopic level looks a lot like wood with long strands of
fiber
> interlocked together all headed in the same direction. Steel has more
welding
> options such as silver brazing, fillet brazing, MIG welding, TIG welding.
When
> looking at the high strength alloys as used in bicycles, if, during the
welding
> process the parent material becomes "molten" then a post treatment will
increase
> strength and the service life. For some reason no one post treats steel
bicycle
> frames. Why? Market forces? With titanium, the more pure it is the higher the strength. Add some
alloys it
> becomes stronger still. Under the microscope the molecule looks like a
snow
> flake with velcro. The molecules interlock in all directions. Welding
doesn't
> disturb the matrix like other materials. Ride or sell aluminum if you like. For me the risk is too
> high. Steve "Speedy" Delaire

I freely admit to being partial to steel bicycle frames but don't you think you were overly excited
when composing that?

Are your analogies to metals' structure and properties supposed to be satirical? There's just enough
similarity to reality to be entertaining.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[Norm]

Where did you learn metallurgy and where did you see these "balls" in the "molecular structure" of
extruded aluminium tubing? Interstitial copper running away? "levers" of copper? Metal alloys are
crystalline structures. Please explain how their "molecules" can "interlock".

There are hundreds of "grades" of aluminium alloys, the 6XXX and 7XXX series typically used in
bicycle frames contain very little Cu by mass, Si and Mg are the main alloying elements.

Norm [email protected]

"S. Delaire \"Rotatorrecumbent\"" <[email protected]> wrote in message
news:<[email protected]>...
> Mike Perhaps I should have started by saying that I have had enough broken aluminum frames that I
> will never trust my life to another ever again. Is you look at the molecular structure of
> aluminum, steel, and titanium they are very different. Aluminum at the microscopic level looks
> like balls individually packed together. It has no significant interlocking grain structure. Pure
> aluminum has such low strength as to be useless and needs to be alloyed with other materials for
> it to be engineered to bicycle applications. Copper is a common alloy ingredient. Problem is that
> when welding, copper tends to "run away" from the heat source. Under the microscope it looks
> similar to what happens to a nylon rope when a match is put to it. The welding rod will have
> higher levers of copper to try and offset this problem and post heat treatment is also used to
> help "straighten" the copper back into place. In practice not all the copper straightens out so
> right next to the weld there will be a small but significant gap of aluminum with the incorrect
> amount or none of the alloying materials. Note... not all grades of aluminum are considered "weld
> able" Pure iron is also useless for bicycles. Alloyed it becomes steel. Steel at the microscopic
> level looks a lot like wood with long strands of fiber interlocked together all headed in the same
> direction. Steel has more welding options such as silver brazing, fillet brazing, MIG welding, TIG
> welding. When looking at the high strength alloys as used in bicycles, if, during the welding
> process the parent material becomes "molten" then a post treatment will increase strength and the
> service life. For some reason no one post treats steel bicycle frames. Why? Market forces? With
> titanium, the more pure it is the higher the strength. Add some alloys it becomes stronger still.
> Under the microscope the molecule looks like a snow flake with velcro. The molecules interlock in
> all directions. Welding doesn't disturb the matrix like other materials. Ride or sell aluminum if
> you like. For me the risk is too high. Steve "Speedy" Delaire
>
>
>
> Mike Jacoubowsky wrote:
>
> > > Some flaws in your thinking here. The success rate is based on a complete structure not
> > > individual welds.
> >
> > Uh, no, that was the flaw in your original post, not mine. You made the claim that a 98% success
> > rate of weld or process or whatever was the case with aluminum, without making any reference
> > whatsoever to a complete structure... you simply extrapolated it out to mean that a bicycle met
> > the criteria. My point was that a bicycle has "x" degree of welds and complexity; what is that
> > 98% figure based upon? Did NASA actually come up with a BLO (Bicycle-like-object) that they
> > based their research on? I doubt
> > it.
> >
> > Could it be that NASA determined a 98% joint success rate based upon an entire spacecraft
> > (including booster rockets)? Who knows. That's exactly the point though. We don't know what the
> > info is based upon.
> >
> > > In the aircraft industry chrome/moly steel is required to be heat treated
> after
> > > welding yet no one in the bicycle industry post treats a steel frame even
> though
> > > the tensile strength could be improved by almost 100% Another example of
> market
> > > forces at work.
> >
> > This is something for others (with a better background in such things) to comment on. However,
> > is 100% improved tensile strength in steel really a relevant factor, given what the tensile
> > strength is in a finished product built from 853? I suspect tensile strength isn't a limiting
> > factor in building a strong, lightweight steel frame, regardless of cost.
> >
> > Those same "market forces at work" are every bit as likely to reward the fool with a lot of
> > money, who is willing to pay huge $$$ for a benefit that's not actually relevant to how a
> > bicycle performs or its durability. "Market forces" don't simply work to bring an item down to
> > its lowest-possible cost.
> >
> > > The titanium alloys being used for bike frames do not require post
> treatment.
> > > During the welding process there are some obvious visual clues if the weld
> is
> > > right or not.
> >
> > Right. So we're back to square one, where we're totally dependent upon the skill of the person
> > building the product to do it correctly.
> >
> > > Again I say aluminum is a cheap abundant material that is easy to mass
> produce
> > > but is not the most reliable.
> >
> > It all depends upon the criteria. If you had, say, $300 to invest in an aluminum or titanium
> > frame, would you still maintain the aluminum frame would be less reliable? If money wasn't an
> > issue and you wanted a 2.6lb frame, do you still think aluminum would be the most reliable
> > (given titanium's record of durability is markedly different below 3lbs vs above)?
> >
> > Any material, brought to the edge of what's possible in terms of fabrication, is going to have
> > problems. This is very common in ultra-light Ti frames, just as it is in stupid-light (that's
> > one category below ultra-light) aluminum frames. At some point you're pushing the material a bit
> > too far and the realities of the real world intrude in ugly ways (when everything's not exactly
> > perfect).
> >
> > This isn't about mass production, but rather about using a material to its best advantage. A
> > properly-built Ti frame is a work of art and should last forever, as should a properly-built
> > aluminum, carbon or steel frame. It's not the material that makes the difference. Nor is it
> > about a 98% joint success rate (which really needs to be defined before it's tossed around any
> > further). It's the overall durability of the finished structure that counts. Or, simply, how the
> > material is used.
> >
> > --Mike-- Chain Reaction Bicycles http://www.ChainReaction.com
> >
> > "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> > news:[email protected]...
> > > Mike Some flaws in your thinking here. The success rate is based on a complete structure not
> > > individual welds. Most all welded aluminum failures happen NEXT to the
> weld
> > > not IN the weld due to the microscopic change in the parent material from
> the
> > > welding process. This means the failure has nothing to do with the
> craftsmanship
> > > of the welder but has everything to do with the nature of the material. In the aircraft
> > > industry chrome/moly steel is required to be heat treated
> after
> > > welding yet no one in the bicycle industry post treats a steel frame even
> though
> > > the tensile strength could be improved by almost 100% Another example of
> market
> > > forces at work. If a long lasting frame is desired titanium makes sense because it is so
> tough.
> > > The titanium alloys being used for bike frames do not require post
> treatment.
> > > During the welding process there are some obvious visual clues if the weld
> is
> > > right or not. At the microscopic level the parent material is not affected
> the
> > > same as aluminum. Titanium frame failures do happen but most often start
> IN the
> > > weld. A craftsmanship problem not a material problem. Part of the NASA welding certification
> > > process was to do samples that were dissected in every possible way, tensile (pull) test,
> > > bend, X ray, dye penetrant, microscopic. The deficiencies in properly welded aluminum were
> easy
> > > to see. Again I say aluminum is a cheap abundant material that is easy to mass
> produce
> > > but is not the most reliable. Just the facts Steve "Speedy" Delaire
> > >
> > >
> > >
> > > Mike Jacoubowsky wrote:
> > >
> > > > > success". They concluded that there is no 100% way to join aluminum.
> Done in the
> > > > > best environment and procedures it can only come to 98 percent, which
> in my mind
> > > > > means 2 out of every 100 bicycle frames will fail.
> > > >
> > > > Taking your information about failure literally, it wouldn't be 2 out of
> 100
> > > > frames failing, but close to one out of five, since a frame represent
> not
> > > > just one point of weld failure, but up to 20.
> > > >
> > > > I'm guessing that it means 2 out of every 100 bicycle frames won't be optimally welded (not
> > > > that 2 out of every 100 will fail). Very few
> designs
> > > > are so close to the edge that they demand absolute perfection in order
> to
> > > > work. The typical aluminum bicycle frame is overbuilt and not dependent upon a 100% perfect
> > > > joint.
> > > >
> > > > > Titanium, on the other hand is certainly the toughest. It kills the
> cutting tools
> > > > > quick, and is hard to bend. Properties that seem nice to have on a
> > > > bicycle.
> > > >
> > > > This seems a bit contradictory. If Titanium is the toughest to build properly, why isn't
> > > > this a concern for a bicycle? When you talk about
> 100%
> > > > reliability in NASA applications, my guess is that that's dependent upon x-raying the welds.
> > > > Sorry, but this isn't done in the bicycle industry. Instead, you're dependent upon someone
> > > > taking all the necessary (and
> tough,
> > > > as you say) steps to do it the right way, with a whole lot of things
> that
> > > > can go wrong along the way. But in the end, it really doesn't matter because Ti bikes, just
> > > > like Aluminum ones, are also built with a
> reasonable
> > > > margin of safety, such that minor imperfections aren't going to cause failure.
> > > >
> > > > --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
> > > >
> > > > "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> > > > news:[email protected]...
> > > > > Pete Before taking up bicycles full time I worked for NASA as a tech. My
> primary role
> > > > > was as a T.I.G. welder but was also certified for bonding (glue) and
> riveting.
> > > > > We made high tech parts from all materials. NASA rates all structures and for that matter
> > > > > all projects by a
> "percentage of
> > > > > success". They concluded that there is no 100% way to join aluminum.
> Done in the
> > > > > best environment and procedures it can only come to 98 percent, which
> in my mind
> > > > > means 2 out of every 100 bicycle frames will fail. Aircraft are REQUIRED to have routine
> > > > > inspections and are repaired
> routinely. How
> > > > > many bike riders routinely inspect their bikes for cracks? Passenger aircraft usually are
> > > > > rated for 20 years service. Fatigue life for aluminum is known to be shorter than other
> > > > > common
> materials.
> > > > > Steel and titanium can be joined to 100% reliability. Done properly. Joining composite
> > > > > structures is also problematic and not able to
> achieve 100%
> > > > > success. Aluminum is cheap, abundant, light and easy to form, weld, and bend,
> important in
> > > > > keeping the cost down for mass production. Titanium, on the other hand is certainly the
> > > > > toughest. It kills the
> cutting tools
> > > > > quick, and is hard to bend. Properties that seem nice to have on a
> bicycle.
> > > > > Steve "Speedy" Delaire
> > > > >
> > > > >
> > > > > "(Pete Cresswell)" wrote:
> > > > >
> > > > > > Just saw a post on alt.mountain-bike ("Foes Customer Service -
> someone else
> > > > > > doin' it right") that contained the statement:
> > > > > >
> > > > > > "Believe it or not, if ridden off-road for that long (minimum it
> seems 5
> > > > > > years) just about any aluminum frame will break."
> > > > > >
> > > > > > I've heard others say that this is nonsense, but source seems pretty
> reliable.
> > > > > >
> > > > > > OTOH, airplane frames last a lot longer than 5 years...
> > > > > >
> > > > > > Comments?
> > > > > > -----------------------
> > > > > > Pete Cresswell
> > > > >
> > > > >
> > > > >
> > > > > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com -
> > > > > The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different
> > > > > Servers! =-----
> > >
> > >
> > >
> > > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The
> > > #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers!
> > > =-----
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

[Harrow]

If Al bike frames are so short lived, then how come you get all those long frame warranties ??

eg. Giant 10 years, Lear 15 years, Cannondale LIFETIME ?

You've all got me worried I'm going to kill myself on my next ride. If I check each time, will I see the cracked welds well in advance of the catastrophic failure everyone is talking about ?

 

[Paul]

I've been worried about alu frames too since hearing all the worries about them (mine only have a 3
year warranty) but people hear have help put my mind at rest. I've seen fairly low end alu frames
with lifetime guarantees too.

I would appear from what I've been told that a well designed alu frame can indeed last a long time.

 

[Qui Si Parla Ca]

Harrow-<< If Al bike frames are so short lived, then how come you get all those long frame
warranties ??

eg. Giant 10 years, Lear 15 years, Cannondale LIFETIME ? >><BR><BR>

Because they know that for most uses, the aluminum frameset, many of which are more robust than some
steel and carbon, will last a lomg time.

It's a game of marketing and future predictions.

Some very thin aluminum/scamdium framesets are not warrantied at all..described as 'racing only'
framesets and some have maximum weights for the rider's.

It just depends. It is not fair to say that aluminum doesn't 'last long' any more than to say that
steel framesets are 'heavy' or titanium are 'expensive or flexy', or that carbon 'doesn't do well
in a crash'.

There are comfy, long lasting aluminum, light steel, stiff and not expensive titanium and carbon
that does well in crashes(ask Mike J).

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[Dashi Toshii]

"Harrow" <[email protected]> wrote in message news:[email protected]...
> If Al bike frames are so short lived, then how come you get all those long frame warranties ??
>
> eg. Giant 10 years, Lear 15 years, Cannondale LIFETIME ?
>
> You've all got me worried I'm going to kill myself on my next ride. If I check each time, will I
> see the cracked welds well in advance of the catastrophic failure everyone is talking about ?

A lot of the older airplanes are made from aluminum alloy and are still flying:

B-52 about 50 years.

C-46/47 over 50 years.

And a lot more.

Dashii
>
>
>
> --
> >--------------------------<
> Posted via cyclingforums.com http://www.cyclingforums.com