Post-recall R-Sys wheel failure

KG writes:

On Jun 14, 9:07Â*am, d p chang wrote:
KG writes:

When the bicycle designer then designs the frame, he/she will make the
cro-moly tubes thin walled in order to make them light.

and they'll also probably go for 'butting' or something as a compromise
at teh 'ends' (welding/general joining/whatever).

2) The reason butted tubes are used in bike construction is: they help
in the stiffness to weight ratio.

maybe i'm falling into a marketting trap, but i always thought that the
butting was mostly for helping builders have more material to
weld/braze/whatever w/ (ie, the thinner wall stuff was trickier to join
well in a mass production environment).

However, they decrease the crash worthiness of a frame. The best
frames from a crash perspective are the cheap straight gauge thick
wall cheap frames from China, but that's not what racers want. The
want a high stiffness to weight ratio.

regardless, i'm not sure most people (other than people jumping/hucking
their bikes off of tall things) are looking for crash worthiness. i'm
differentiating between lasting w/ normal use and surviving multiple
crashes. having wrecked a few times (and bikes) there are some things
that are just going to f*ck-up a thingee (bike/car/rocket/whatever)
regardless of what it is made of.

\p
---
The computer can't tell you the emotional story. It can give you the
exact mathematical design, but what's missing is the eyebrows.
- Frank Zappa

On Jun 14, 2:46*pm, d p chang wrote:

maybe i'm falling into a marketting trap, but i always thought that the
butting was mostly for helping builders have more material to
weld/braze/whatever w/ (ie, the thinner wall stuff was trickier to join
well in a mass production environment).


Dumbass -

Your assumption is completely correct.


regardless, i'm not sure most people (other than people jumping/hucking
their bikes off of tall things) are looking for crash worthiness.


Agreed.


thanks,

Kurgan. presetned by Gringioni.

In article ,
"Sandy" wrote:

Dans le message de ,
Michael Press a réfléchi, et puis a déclaré :
In article ,
"Sandy" wrote:

Dans le message de
, Michael
Press a réfléchi, et puis a déclaré :
In article ,
"Tom Kunich" cyclintom@yahoo. com wrote:

"Ryan Cousineau" wrote in message
]...

As Mavic themselves note, instant failure of the spokes (which are
the busted bits of the wheel) would cause the hub to hit the
ground, not the fork.

Actually it would have caused the hub to hit the rim. And strangely
enough there didn't seem to be a spot on the rim crushed from such
an occurence. At least in the picture I saw.

I think what happened was a more-or-less sequential failure of the
spokes, which would have led to a relatively gentle (but
exceedingly bizarre) let-down of the bike.

Of course this could have caused the bike to washout before the hub
hit the rim. Though I doubt it.

All I'm saying is that we can't tell what happened until Mavic
looks it over. I still think that experimental grade components
shouldn't be used by anyone but professional racers.

Unfortunately it appears that anyone with money can now buy stuff
that professional riders wouldn't even want to try.

Why send it to Mavic? Semd it to
a laboratory that the victim hires.
Let Mavic see it afterwards.

There is/was no victim.

3. A person or living creature destroyed by,
or suffering grievous injury from, another,
from fortune or from accident; as, the victim of a defaulter;
the victim of a railroad accident.

Yeah - 3rd best in some literalist's list.
Take a moment to look up "context" and "connotation".
That could be enlightening.

Okay, now we are negotiating. (If I had only doped
I would have come in first.) Dictionaries cannot put
all the varying definitions first. Some must appear
before others. When they want to qualify a definition
they do it explicitly with "archaic", or "slang", or
"sometimes", or mention that is a technical term in
some field of endeavor.


PS: there was no victim in the context of, and with the connotation in your
comment. Or did you imply Mavic's being the victim of RBR? Not to mention
RBT (Oops! I said not to mention. Sorry.)

Oh, now we are not negotiating.
"victim of a railroad accident"

"I landed on my head and broke my shoulder."

There is a victim of a bicycle crash.

--
Michael Press

In article
,
KG wrote:

On Jun 13, 10:49Â*pm, Michael Press wrote:
In article
,





Â*KG wrote:
On Jun 12, 2:54Â*am, Michael Press wrote:
In article
,

Â*KG wrote:
On Jun 11, 8:51Â*pm, Michael Press wrote:
In article
,

Â*KG wrote:
On Jun 11, 2:00Â*pm, Michael Press wrote:
In article
,

Â*KGring wrote:
On Jun 10, 7:00Â*pm, "Mike Jacoubowsky"
wrote:
"Tom Kunich" cyclintom@yahoo. com wrote in messagenews:G7GdnemzlOIRWLLXnZ2dnUVZ_tidnZ2d@earth link.com...

"Mike Jacoubowsky" wrote in message
.. .

Since down tubes act in tension a buckled down tube is not
the proximate cause of failure. How did those frames fail
that had buckled down tubes?

Frontal impact. Steel frames & forks were typically not very strong
in such situations. You and I may be interpreting this thread
differently; I am not talking about JRA (Just Riding Along) failures.

Try hitting a dog while going 20 mph. A well known and expensive
carbon bike head tube broke off like it was paper mache'. A steel bike
wouldn't fail that way.

I assume you're joking. You are, aren't you? Not that I have any
personal experience with such things...

snip

Dumbass -

Unfortunately, he's not joking.

The reason some ignorant armchair engineers (like Kunich) get this
idea that steel is not as prone to failure as materials like carbon is
that in the case of bicycle frames steel will give audible signs
(creaking) of an impending failure while materials like carbon and
aluminum will do so at a much lesser extent or not at all. The result
is that people will check their steel frame and stop riding it once
they discover the crack, while a frame constructed of the other
materials will continue to be ridden if not inspected, leading to its
inevitable demise. The result is that steel gets this undeserved
reputation as more resistant to failure.

That _is_ a manner in which it is more resistant to catastrophic failure.
Without going into what is deserved or not,
it is a real reason for a good reputation.

Dumbass -

The negligance of the operator?

I guess.

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

As a material it really is. It absorbs energy while failing.
Technical terms: ductile, tough. Steel is high in both.
Now do not flip-flop on me and reply by talking
about designing the whole system.

The resistance to failure of any part is determined by the material
properties, design and intended use.

Crikey, you done it.

Dumbass -

The design is mentioned because it's as important as material
properties.

I used to be a tireless advocate of titanium, but after just a few
years of working with all these materials, I realized the error of my
ways.

Failing to account for design and purpose would be just as negligent
as failing to account for material properties.

thanks,

Kurgan. presented by Gringioni.

Why did you bother to say

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

???

Steel _is_ more resistant to catastrophic failure when we are talking
about _materials_. If you do not want to talk about materials then do
not; but don't pull a bait and switch.

Dumbass -

You're missing the point.

I addressed your point directly,
the point you wanted to make
that steel has an undeserved
reputation. As a material
steel is tougher than Al,
and CFRP has zero toughness.
That is all.



Dumbass -

You don't know what you're talking about in the instance of bicycle
frames. Let me expound further.

I said straight out that I am talking about steel as
a material, as you were at the point I replied.
As a material, steel is tougher than other materials
used in bicycle frames.

--
Michael Press

In article
,
KG wrote:

On Jun 13, 10:49Â*pm, Michael Press wrote:
In article
,





Â*KG wrote:
On Jun 12, 2:54Â*am, Michael Press wrote:
In article
,

Â*KG wrote:
On Jun 11, 8:51Â*pm, Michael Press wrote:
In article
,

Â*KG wrote:
On Jun 11, 2:00Â*pm, Michael Press wrote:
In article
,

Â*KGring wrote:
On Jun 10, 7:00Â*pm, "Mike Jacoubowsky"
wrote:
"Tom Kunich" cyclintom@yahoo. com wrote in messagenews:G7GdnemzlOIRWLLXnZ2dnUVZ_tidnZ2d@earth link.com...

"Mike Jacoubowsky" wrote in message
.. .

Since down tubes act in tension a buckled down tube is not
the proximate cause of failure. How did those frames fail
that had buckled down tubes?

Frontal impact. Steel frames & forks were typically not very strong
in such situations. You and I may be interpreting this thread
differently; I am not talking about JRA (Just Riding Along) failures.

Try hitting a dog while going 20 mph. A well known and expensive
carbon bike head tube broke off like it was paper mache'. A steel bike
wouldn't fail that way.

I assume you're joking. You are, aren't you? Not that I have any
personal experience with such things...

snip

Dumbass -

Unfortunately, he's not joking.

The reason some ignorant armchair engineers (like Kunich) get this
idea that steel is not as prone to failure as materials like carbon is
that in the case of bicycle frames steel will give audible signs
(creaking) of an impending failure while materials like carbon and
aluminum will do so at a much lesser extent or not at all. The result
is that people will check their steel frame and stop riding it once
they discover the crack, while a frame constructed of the other
materials will continue to be ridden if not inspected, leading to its
inevitable demise. The result is that steel gets this undeserved
reputation as more resistant to failure.

That _is_ a manner in which it is more resistant to catastrophic failure.
Without going into what is deserved or not,
it is a real reason for a good reputation.

Dumbass -

The negligance of the operator?

I guess.

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

As a material it really is. It absorbs energy while failing.
Technical terms: ductile, tough. Steel is high in both.
Now do not flip-flop on me and reply by talking
about designing the whole system.

The resistance to failure of any part is determined by the material
properties, design and intended use.

Crikey, you done it.

Dumbass -

The design is mentioned because it's as important as material
properties.

I used to be a tireless advocate of titanium, but after just a few
years of working with all these materials, I realized the error of my
ways.

Failing to account for design and purpose would be just as negligent
as failing to account for material properties.

thanks,

Kurgan. presented by Gringioni.

Why did you bother to say

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

???

Steel _is_ more resistant to catastrophic failure when we are talking
about _materials_. If you do not want to talk about materials then do
not; but don't pull a bait and switch.

Dumbass -

You're missing the point.

I addressed your point directly,
the point you wanted to make
that steel has an undeserved
reputation. As a material
steel is tougher than Al,
and CFRP has zero toughness.
That is all.



Dumbass -

You don't know what you're talking about in the instance of bicycle
frames. Let me expound further.

Why aren't bikes regularly made out of Aermet 310 (the strongest,

Because bicycles do not need the extra toughness.

--
Michael Press

On Jun 15, 11:58*am, Michael Press wrote:
In article
,





*KG wrote:
On Jun 13, 10:49*pm, Michael Press wrote:
In article
,

*KG wrote:
On Jun 12, 2:54*am, Michael Press wrote:
In article
,

*KG wrote:
On Jun 11, 8:51*pm, Michael Press wrote:
In article
,

*KG wrote:
On Jun 11, 2:00*pm, Michael Press wrote:
In article
,

*KGring wrote:
On Jun 10, 7:00*pm, "Mike Jacoubowsky"
wrote:
"Tom Kunich" cyclintom@yahoo. com wrote in messagenews:G7GdnemzlOIRWLLXnZ2dnUVZ_tidnZ2d@earth link.com...

"Mike Jacoubowsky" wrote in message
.. .

Since down tubes act in tension a buckled down tube is not
the proximate cause of failure. How did those frames fail
that had buckled down tubes?

Frontal impact. Steel frames & forks were typically not very strong
in such situations. You and I may be interpreting this thread
differently; I am not talking about JRA (Just Riding Along) failures.

Try hitting a dog while going 20 mph. A well known and expensive
carbon bike head tube broke off like it was paper mache'. A steel bike
wouldn't fail that way.

I assume you're joking. You are, aren't you? Not that I have any
personal experience with such things...

snip

Dumbass -

Unfortunately, he's not joking.

The reason some ignorant armchair engineers (like Kunich) get this
idea that steel is not as prone to failure as materials like carbon is
that in the case of bicycle frames steel will give audible signs
(creaking) of an impending failure while materials like carbon and
aluminum will do so at a much lesser extent or not at all. The result
is that people will check their steel frame and stop riding it once
they discover the crack, while a frame constructed of the other
materials will continue to be ridden if not inspected, leading to its
inevitable demise. The result is that steel gets this undeserved
reputation as more resistant to failure.

That _is_ a manner in which it is more resistant to catastrophic failure.
Without going into what is deserved or not,
it is a real reason for a good reputation.

Dumbass -

The negligance of the operator?

I guess.

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

As a material it really is. It absorbs energy while failing.
Technical terms: ductile, tough. Steel is high in both.
Now do not flip-flop on me and reply by talking
about designing the whole system.

The resistance to failure of any part is determined by the material
properties, design and intended use.

Crikey, you done it.

Dumbass -

The design is mentioned because it's as important as material
properties.

I used to be a tireless advocate of titanium, but after just a few
years of working with all these materials, I realized the error of my
ways.

Failing to account for design and purpose would be just as negligent
as failing to account for material properties.

thanks,

Kurgan. presented by Gringioni.

Why did you bother to say

The issue I have with it is people have this incorrect idea that steel
is more resistant to catostrophic failure when it really isn't.

???

Steel _is_ more resistant to catastrophic failure when we are talking
about _materials_. If you do not want to talk about materials then do
not; but don't pull a bait and switch.

Dumbass -

You're missing the point.

I addressed your point directly,
the point you wanted to make
that steel has an undeserved
reputation. As a material
steel is tougher than Al,
and CFRP has zero toughness.
That is all.

Dumbass -

You don't know what you're talking about in the instance of bicycle
frames. Let me expound further.

I said straight out that I am talking about steel as
a material, as you were at the point I replied.
As a material, steel is tougher than other materials
used in bicycle frames.



Dumbass -

Not necessarily.

As I've pointed out muliple times, in order to compete in the
stiffness to weight ratio, designers have to use steel tubes that has
a much thinner wall than aluminum, carbon or titanium.

Depending on which specific frames/designs one is examining, the steel
frame can be more prone to failure.

thanks,

Kurgan. presented by Gringioni.

"Michael Press" wrote in message
...

I said straight out that I am talking about steel as
a material, as you were at the point I replied.
As a material, steel is tougher than other materials
used in bicycle frames.

Michael, Henry isn't an engineer. He doesn't understand what you're talking
about when you say, "toughness". You have to explain your point and not
assume that he understands. It isn't like he's stupid, he just acts that way
to be cool.

"Michael Press" wrote in message
...

Why aren't bikes regularly made out of Aermet 310 (the strongest,

Because bicycles do not need the extra toughness.

And because Aermet is very difficult to work since it is about as tough as
most tool steels.

"Michael Press" wrote in message
...

There is a victim of a bicycle crash.

Remember that Sandy is a lawyer and has rather precise definitions of terms.

On Jun 15, 2:00*pm, "Tom Kunich" cyclintom@yahoo. com wrote:
"Michael Press" wrote in message

...



I said straight out that I am talking about steel as
a material, as you were at the point I replied.
As a material, steel is tougher than other materials
used in bicycle frames.

Michael, Henry isn't an engineer. He doesn't understand what you're talking
about when you say, "toughness". You have to explain your point and not
assume that he understands. It isn't like he's stupid, he just acts that way
to be cool.



Dumbass -

My degree was in computer science, but my dad is a Phd in Civil
Engineering and was a professor in that field at University of
Wyoming. One of the classes he taught was Mechanics of Materials. I've
been around this stuff my whole life.

thanks,

Kurgan. presented by Gringioni.