Post-recall R-Sys wheel failure

In article ,
"Tom Kunich" cyclintom@yahoo. com wrote:

"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.

There are many different tool steels, falling roughly into 11 different grades.
Some are created with toughness in mind but many are not. The tool steel used in a
drill bit has a very different degree of toughness than those that are used in a
knife or a chisel. So your statement is overly broad.

--
tanx,
Howard

Caught playing safe
It's a bored game

remove YOUR SHOES to reply, ok?

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.

Why aren't bikes regularly made out of Aermet 310 (the strongest,
toughest steel alloy, the one from which tank armor is constructed)?
Answer: toughness isn't the most important consideration in bike frame
fabrication. The riders want performance and not breaking in a crash
is, at best, a tertiary consideration. The primary consideration for
performance is the weight to stiffness ratio. Therefore, when a
designer chooses a steel alloy to go with, he/she will chose a chrome
molybdenum steel alloy instead of the toughest alloy, Aermet 310.

When the bicycle designer then designs the frame, he/she will make the
cro-moly tubes thin walled in order to make them light. The wall
thickness will have to be very thin indeed for the steel frame to keep
up with the stiffness to weight ratio of the equivalent aluminum or
carbon frame. Aluminum is only a third the weight of steel and carbon
is a fourth the weight. So the tube thickness will have to be very
thin indeed. For a given stiffness to weight ratio, a chrome
molybdenum steel bike may be more prone to failure than an aluminum or
carbon frame simply because the designer has to use far less cro-moly
to get the same weight to stiffness ratio as a composite frame.

Let me repeat that last sentence: For a given stiffness to weight
ratio, a chrome molybdenum steel bike may be more prone to failure
than an aluminum or carbon frame simply because the designer has to
use far less cro-moly to get the same weight to stiffness ratio as a
composite frame.


thanks,

Kurgan. presented by Gringioni.

Van Haute's team back at some point in the mid 90's (Mrs T's Pierogies?)
had Aermet frames. I think they had them more as a sponsorship from the
material supplier than as a sponsorship from the framebuilder himself.

I don't know how the cost of Aermet tubing compares to other types of
metal tubing, but the hardening process described on the wiki page would
mean fewer framebuilders could afford the tank, oven and freezer needed
for the process, especially on a mass production scale. If you will
recall, it was noted that it's far cheaper and forgiving to weld an
aluminum frame for a given weight than one out of steel. All this adds
to the cost and doesn't touch the factors of machining and shaping the
tubing or material suitability.

In article
,
KG wrote:

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





Â*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.



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.

Tough is a technical term in materials science.
Steel is tougher than CFRP.

--
Michael Press

On Jun 16, 12:08*am, Michael Press wrote:
In article
,





*KG wrote:
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.

Tough is a technical term in materials science.
Steel is tougher than CFRP.



Dumbass -

The point is that it's not necessarily more resistant to breaking in
bicycle frames.

Tank armor, yes. Battleships, yes. Oil tankers, yes. Bicycle frames,
no.

Because the designers use such thin wall tubing and also because the
loads in a twin triangle frame are axial.

Another application where steel isn't the most desirable material is
lighting trusses. They're all made out of aluminum. One could make a
truss that has the same dimensions with thin wall steel tubing, but it
won't be as resistant to buckling. Same with aircraft frames. They're
aluminum and the upcoming newest models go for carbon.

This is what a designer looks at when designing a truss. (a bicycle
frame with its twin triangle construction has the same basic
principles as a truss - the triangles produce axial loads)

http://en.wikipedia.org/wiki/Buckling

Steel is definitely an extremely strong material, but in the thin
walled configurations used in racing bicycle frames, it is prone to
local buckling.

thanks,

Kurgan. presented by Gringioni.

"Michael Press" wrote in message
...

Tough is a technical term in materials science.
Steel is tougher than CFRP.

So you copy 160 lines of writing in order to make a 13 word reply.

On Jun 16, 1:26*am, KG wrote:


Another application where steel isn't the most desirable material is
lighting trusses. They're all made out of aluminum. One could make a
truss that has the same dimensions with thin wall steel tubing, but it
won't be as resistant to buckling.


Dumbass -

I should be more specific. The tubes could have the same outside
dimensions and the center to center distance of the main members of
the truss would be the same. The tubing for steel would have to be
more thin wall in the steel version to be the same weight as the
aluminum version. One third the wall thickness since steel is roughly
three times as dense as aluminum.

If the wall thickness in the aluminum truss is sufficiently thin, the
corresponding steel truss would have a very low ability to withstand
local buckling.

thanks,

Kurgan. presented by Gringioni.

Has anyone heard any more news from Mavic about the R-sys wheels. I am
also wondering the consumer product safety commission is investigating
the Mavic r-sys wheels. Perhaps this is why the have been silent...?


On Jun 9, 12:16*pm, "Robert Chung"
wrote:
http://www.velonews.com/article/9305...rience---a-pos...

On Jun 25, 9:26*pm, hizark21 wrote:
Has anyone heard any more news from Mavic about the R-sys wheels. I am
also wondering the consumer product safety commission is investigating
the Mavic r-sys wheels. Perhaps this is why the have been silent...?



Dumbass -

The Consumer Product Safety Commission isn't going to worry about
botique wheels purchased by a small group of Masters Fatties.

The bigger worry for Mavic will be a class action lawsuit. That's a
good reason to stay silent.

thanks,

Kurgan. presented by Gringioni.

On Jun 26, 12:52*am, KG wrote:
On Jun 25, 9:26*pm, hizark21 wrote:

Has anyone heard any more news from Mavic about the R-sys wheels. I am
also wondering the consumer product safety commission is investigating
the Mavic r-sys wheels. Perhaps this is why the have been silent...?

Dumbass -

The Consumer Product Safety Commission isn't going to worry about
botique wheels purchased by a small group of Masters Fatties.

The bigger worry for Mavic will be a class action lawsuit. That's a
good reason to stay silent.

thanks,

Kurgan. presented by Gringioni.

It depends if there was a complaint filed. It is very likely that this
type of failure could cause injury. Just imagine if someone were
riding down a long hill. I would think that Mavic would suspend the
sales of the r-sys wheel at a minimum.

"hizark21" wrote in message
...

It depends if there was a complaint filed. It is very likely that this
type of failure could cause injury. Just imagine if someone were
riding down a long hill. I would think that Mavic would suspend the
sales of the r-sys wheel at a minimum.

Psst - they're French. That means that they're pretty much proof against
lawsuits here since most of their investment is only in France which doesn't
have the same sort of liability laws.

I'm not sure whether or not I like that idea. One the one hand I hate the
way anyone can sue anyone for any stupid reason. On the other hand, this
case shows what can happen if a company doesn't pay attention to liability
because they can dodge most of the bullet from carelessness.