Fork survived, head tube didn't!

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07/BaytonsBikeCrashPhSpt

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07/BaytonsCrashedBikePhSpt

interesting indeed.

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

How can a crash destroy the bottom of your head tube outwards? I've
seen stuff like that after casing a bmx or mtb jump landing, but hard
to see how that would happen on a road bike....

/s

Scott Gordo said:

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

Quoted message said:

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

Quoted message said:

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

How can a crash destroy the bottom of your head tube outwards? I've
seen stuff like that after casing a bmx or mtb jump landing, but hard
to see how that would happen on a road bike....

/s

It looks almost like something hit the fork from the left, or the bike
was lying on the ground on its left side and something landed on it.

jim beam said:

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07/BaytonsBikeCrashPhSpt

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07/BaytonsCrashedBikePhSpt

interesting indeed.

wow, a whole day passes and the stupidity contestants don't comment on
how cfrp is "brittle", how it should all be aerospace spec and how it is
in fact satan's spawn.

but how silly of me! to expect sufficient interest in commenting
presumes an interest in the /subject matter/ rather than trying to bleat
ridiculous personal dislike of a random anonymous troll they found on
the interweb. on their employers time no less.

Scott Gordo said:

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

How can a crash destroy the bottom of your head tube outwards? I've
seen stuff like that after casing a bmx or mtb jump landing, but hard
to see how that would happen on a road bike....

but that's what makes them so dramatic...

jim beam said:

Quoted message said:

Rik O'Shea said:

Interesting crash photos. The fork steering column looks ok, the head
tube is kaput.

Quoted message said:

Quoted message said:

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

Quoted message said:

Quoted message said:

http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...

Quoted message said:

interesting indeed.

wow, a whole day passes and the stupidity contestants don't comment on
how cfrp is "brittle", how it should all be aerospace spec and how it is
in fact satan's spawn.

Are you suggesting that a metal head tube would have erupted like that
one did? I've never seen the like with any kind of metal frame.

The question remains: was the frame's structural failure a result of
the crash, or the cause?

Chalo

Chalo said:

jim beam said:

Quoted message said:

Rik O'Shea wrote:
> Interesting crash photos. The fork steering column looks ok, the head
> tube is kaput.
> http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...
> http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...
interesting indeed.

wow, a whole day passes and the stupidity contestants don't comment on
how cfrp is "brittle", how it should all be aerospace spec and how it is
in fact satan's spawn.

Are you suggesting that a metal head tube would have erupted like that
one did? I've never seen the like with any kind of metal frame.

no, the whole frame would completely mangled if it were metal
encountering a force of that magnitude.

Quoted message said:

The question remains: was the frame's structural failure a result of
the crash, or the cause?

result.

if that material were "brittle", the head tube would have broken its way
out and pieces would have broken from head tube leaving an exit hole
proportional to the size of the steer tube. instead however, we see the
pieces of the head tube are still attached, /and/ fracture consistent
with high energy absorption - so to the crash necessary to brute-force
the steer tube through a breach that is resisting it sufficiently to
re-close itself after exit must have been significant.

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

jim beam said:

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

Bottom line - I've never seen a steel frame do that, no matter what
the crash conditions. CF still sucks.

jim beam said:

Chalo said:

jim beam said:

> Rik O'Shea wrote:
>> Interesting crash photos. The fork steering column looks ok, the head
>> tube is kaput.
>> http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...
>> http://www.cyclingnews.com/photos.php?id=/photos/2007/sep07/newport07...
> interesting indeed.
wow, a whole day passes and the stupidity contestants don't comment on
how cfrp is "brittle", how it should all be aerospace spec and how it is
in fact satan's spawn.

Are you suggesting that a metal head tube would have erupted like that
one did? I've never seen the like with any kind of metal frame.

no, the whole frame would completely mangled if it were metal
encountering a force of that magnitude.

So, given similar conditions, metal and carbon fiber behave differently.
What is the property (or properties) in respect of which they exhibit
different behavior? Brittleness comes to mind, but you've ruled that out.

Quoted message said:

Quoted message said:

The question remains: was the frame's structural failure a result of
the crash, or the cause?

result.

if that material were "brittle", the head tube would have broken its way
out and pieces would have broken from head tube leaving an exit hole
proportional to the size of the steer tube.

This sounds like something out of a Roadrunner cartoon. Coyote runs into
stone wall and leaves a coyote-shaped hole.

Quoted message said:

instead however, we see the
pieces of the head tube are still attached,

That hardly seems dispositive -- shards of safety glass are held in place
by a plastic layer, but that doesn't mean that the material as a whole
isn't brittle.

/and/ fracture consistent

Quoted message said:

with high energy absorption - so to the crash necessary to brute-force
the steer tube through a breach that is resisting it sufficiently to
re-close itself after exit must have been significant.

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

Gary Young said:

On Fri, 07 Sep 2007 05:55:45 -0700, jim beam wrote:

Quoted message said:

Quoted message said:

if that material were "brittle", the head tube would have broken its way
out and pieces would have broken from head tube leaving an exit hole
proportional to the size of the steer tube.

This sounds like something out of a Roadrunner cartoon. Coyote runs into
stone wall and leaves a coyote-shaped hole.

OK, that made my day...

jim beam said:

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

Eye, mote, beam, "beam".

still me said:

jim beam said:

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

Bottom line - I've never seen a steel frame do that, no matter what
the crash conditions.

it won't - it'll plastically deform and do so at a lower stress level.

Quoted message said:

CF still sucks.

no it doesn't - on a specific modulus basis, it's about the best
material out there right now.

i don't understand the problem people have with a superior [stronger]
material - just because the deformation mechanism is different.
stronger is better. lighter is better. more fatigue resistant is
better. carbon is impressive on all three counts.

Peter Cole said:

jim beam said:

bottom line, i'd say this a pretty impressive result. the chumps that
are now stand about having bleated that cfrp is "brittle" must be
looking at this and feeling pretty damned stupid. or they should be -
assuming they ever knew anything about deformation and fracture in the
first place [which they haven't yet].

Eye, mote, beam, "beam".

er, that fracture evidences /significant/ energy absorption...

"jim beam" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

still me said:

Bottom line - I've never seen a steel frame do that, no matter what
the crash conditions.

it won't - it'll plastically deform and do so at a lower stress level.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

Quoted message said:

Quoted message said:

CF still sucks.

no it doesn't - on a specific modulus basis, it's about the best material
out there right now.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

Quoted message said:

i don't understand the problem people have with a superior [stronger]
material - just because the deformation mechanism is different. stronger
is better. lighter is better. more fatigue resistant is better. carbon
is impressive on all three counts.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

Jambo said:

"jim beam" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

still me said:

Bottom line - I've never seen a steel frame do that, no matter what
the crash conditions.

it won't - it'll plastically deform and do so at a lower stress level.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

Quoted message said:

Quoted message said:

CF still sucks.

no it doesn't - on a specific modulus basis, it's about the best material
out there right now.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

Quoted message said:

i don't understand the problem people have with a superior [stronger]
material - just because the deformation mechanism is different. stronger
is better. lighter is better. more fatigue resistant is better. carbon
is impressive on all three counts.

Yeah, because "for a 6061 with E = 69GPa, and 275MPa yield, that gives an
elastic
deformation limit of 0.275/69 x 100% = 0.04%."

if you want to make meat out of that typo mr. modulus, try omitting the
formula - because that gives the correct answer. moron.

On Mon, 10 Sep 2007 19:38:00 -0400, in rec.bicycles.tech "Jambo"

[email protected] said:

Ah, the shrieking is reserved for jim beamer. I don't see you criticizing
his rather pedestrian insults... but that's okay, because that IS the
point...

I didn't read 'em and, most likely, won't. There are some on whom I
won't waste my writing. < SHRUG > I usually get paid for writing.

Jones