Re: Steel frames and le Tour

jim beam <spamvortex@xxxxxxxxxxxxxxx> writes:

Tim McNamara wrote:
jim beam <spamvortex@xxxxxxxxxxxxxxx> writes:

Tim McNamara wrote:
jim beam <spamvortex@xxxxxxxxxxxxxxx> writes:

er, steel's failure is catastrophic. and not always slow,
certainly not in a crash. fatigue failure is typically slow
crack nucleation, increasingly rapid crack growth, then
catastrophic fracture.

carbon's failure in crash mode is catastrophic, so no real
difference there [except for the carbon being stronger of
course]. carbon's failure in fatigue, if you can wait around
that long, is slow disintegration accompanied by much audible
cracking, creaking, and otherwise voluble telltales. if you're
standing on a plank of wood, and it starts to creak and groan,
it's rare that you wouldn't have time to move off safely. for
some reason though, when it comes to carbon, the fredly world of
r.b.t seems unable to understand and apply these same principles
to carbon bike components, and thus they desire to ignore those
warning signs, and indulge their desire for presumptive
scare-mongering. perverse.

I don't ever remember seeing a steel frame (or aluminum or
titanium) with the fork broken off or the head tube snapped off
in a crash, but have seen multiple examples of this in photos of
crashes involving carbon fiber bikes. That suggests that there
is indeed a significant difference the the resistance of metallic
versus composite materials to catastrophic failure. Given that
bicycles have little redundancy in their designs, this is a
sigificant issue.

1. your kill file seems to have died. that's a shame.

Trying out Emacs Gnus again, don't have a kill file set up for it
yet. Oh well, we'll both live.

2. no it's not. steel or ti or aluminum buckles in this situation -
the fact that the two now-failed parts are still hanging on to each
other is irrelevant because the rider is still on his ass. what
matters is the stress level at which failure occurs, and what the
stress history was prior.

Not quite. What matters is if the material fails catastrophically or
provides some margin of safety to provide a chance of retaining some
control over the bike.

quality carbon does - it's stronger.

Define "stronger" in this context, jim: impact resistance, fracture
toughness, fatigue resistance, tensile strength, etc. etc.

Buckling under an impact may not be catastrophic in that you may
still be able to control the bike to a degree (e.g., hitting a bad
pothole or a tree branch or something around a fast corner). If
the fork blades, steerer or top and/or down tubes snap, you're well
and truly fucked.

you're deluding yourself.

Breaking a fork or a top/down tube is OK in beamworld, then?

There's lots of ignorance in bike design about this- for example,
treating the fork as a crumple zone to protect the frame.

eh? where the heck to you get that fantasy from???

Well, from reading that opinion in books on frame building (Tony
Oliver, for one), from reading bike magazines over the past 30+ years,
from posts in this newsgroup, etc. Lots of "dude, if your fork had
bent it would have saved your frame" comments: the fork as crumple zone.

It's a misplaced priority. The rider is better off with a buckled
frame than a buckled fork.

set up a straw man, then attack it? what a retard!

Perhaps you just need to read more attentively, jim.

3. if you want to argue that some carbon quality is crap, go
ahead, but a blanket condemnation of all carbon, a material and a
process or failure mechanism you don't understand, is utterly
retarded. timmy.

Some carbon fiber quality certainly is crap, whether in the
material itself, in the resin used, the construction method used by
the bike makerespecially as regards inclusions and voids in the
joints, etc. A blanket condemnation of all carbon? No. But then
you have always had a preference to reply to what you wish someone
had said rather that what they really did say. Your determined
resistance to being bothered by facts remains intact. You might
benefit from reading Max Wertheimer's book _Productive Thinking_.

wow, that's perverse - you accuse me of disregarding facts, yet i'm
one of the few people here actually bothering to provide them.
shame your comprehension skills are so low. [but you're a retard,
so what else should we expect?]

You appear, as per your usual approach to things, to confuse your
opinion with facts. This far the only "fact" you've offered boils
down to "carbon fiber- it's stronger." Nonspecific at best and not
really a ringing endorsement of the comprehensiveness of your
knowledge base.

That aside, it is clear from observation that CF bikes are more prone
to catastrophic failure in foreseeable cycling events (e.g., crashes).

bull***.

Observable reality.

We also don't yet know about CF bikes and aging over time.

bull***.

OK, jim, tell the world what happens to carbon fiber and resin matrix
composites with prolonged UV exposure, road salt and other chemicals,
galvanic corrosion, etc. Do we have your personal guarantee that CF
is 100% inert as a qualified, expert metallurgist?

There are reports of CF frames and forks fracturing and injuring
their riders in normal riding situations; given that the installed
user base of CF bikes is a tiny fraction of steel bikes, the
prevalence of such failures seems to be several orders of magnitude
higher for CF than for steel.

you don't know the facts so that's bull***.

And you are offering no facts, merely calling things "bull***."
Unfortunately that has been your usual defense for years when you are
caught with your pants down.

CF has excellent strength-to-weight characteristics but there is of
course much more to its suitability to any specific application
than that one parameter.

bullshitter.

Ah, the implicit admission of defeat that is ad hominem.

Steel is a mature technology and carbon fiber is not.

bull***.

Really? Carbon fiber products have reached their final forms already?
There will be no more significant advances in the material?

New research into using nanotechnology such as carbon nanotubes
will probably revolutionize an already rapidly changing material
and in time will most likely alleviate all of the obvious concerns
in it's application to cycling (impact resistance, fracture
initiation, fracture toughness, changes in the material over time,
etc.).

wow, that is /utter/ bull***!!! regurgitating buzzwords without
knowing *** about their use or application or implication simply
makes you look even more of a retard than we already know you to be
timmy.

Since you don't bother to reveal the extent of your knowledge about
these matters, what are we to make of your cognitive limitations?
It's easy to hurl the words "bull***" at people from behind your
little sock puppet.

There would be benefits to this in cycling as well as other
industries (cars, housing, etc.) as CF is more easily adaptable in
terms of shaping to purpose than is steel.

fucking retard.

You're entertaining as always, jim, if a bit predictable.
.

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