CFRP drawbacks

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

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

Nothing. CFRP talks to you before breaking, otherwise it sings in a
microphone. ("aerospace industry" knowledge, you know...)

It's also indestructible, has infinite fatigue life, can survive multiple
crashes with no problems whatsoever.

And if you have any other questions, just go here:
www.CFWhisperers.com

Ask for "jim".

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

Dear I,

As far as I can see, the chief drawback of carbon-fiber is that it
offers little practical advantage over steel, aluminum, or titanium
for bicycles.

That is, the weight savings are trivial for 99.9% of bicyclists. Only
a stop watch or an amazingly close sprint will reveal the speed
improvement gained by reducing the weight of the bicycle plus rider by
1% (two pounds for a 200-lb bike and rider).

(The same is true for the alleged vibration reductions, which are
small enough that they're debatable, or for the increased strength,
which isn't leading to fewer failures because the metal parts are
usually strong enough.)

In return for carbon-fiber parts that may be lighter and stronger than
metal parts, you get parts that are much more prone to damage that is
much harder to detect--except to your wallet, which takes an
impressive beating.

In other words, a dropped chain can leave you wondering whether your
expensive carbon-fiber frame is safe to ride, or even certain that
it's been destroyed. A crash where the whole carbon-fiber bike tumbles
and bangs into things leaves the whole frame suspect, if not
dramatically shattered.

This is less of a problem for a sponsored pro racer, who values the
tiny weight savings, routinely throws damaged equipment away during
the season, and expects to be riding a new bike next year, if not next
month.

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

Cheers,

Carl Fogel

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

Quoted message said:

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

Dear I,

As far as I can see, the chief drawback of carbon-fiber is that it
offers little practical advantage over steel, aluminum, or titanium
for bicycles.

That is, the weight savings are trivial for 99.9% of bicyclists. Only
a stop watch or an amazingly close sprint will reveal the speed
improvement gained by reducing the weight of the bicycle plus rider by
1% (two pounds for a 200-lb bike and rider).

(The same is true for the alleged vibration reductions, which are
small enough that they're debatable, or for the increased strength,
which isn't leading to fewer failures because the metal parts are
usually strong enough.)

In return for carbon-fiber parts that may be lighter and stronger than
metal parts, you get parts that are much more prone to damage that is
much harder to detect--except to your wallet, which takes an
impressive beating.

In other words, a dropped chain can leave you wondering whether your
expensive carbon-fiber frame is safe to ride, or even certain that
it's been destroyed. A crash where the whole carbon-fiber bike tumbles
and bangs into things leaves the whole frame suspect, if not
dramatically shattered.

This is less of a problem for a sponsored pro racer, who values the
tiny weight savings, routinely throws damaged equipment away during
the season, and expects to be riding a new bike next year, if not next
month.

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

Cheers,

Carl Fogel

Wash your keyboard out... pagan!

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

One full of mines and cowpats :-)

Quoted message said:

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else
in regular daily use of an ordinary city rider.

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

I think the primary disadvantage of CFRP is that the manufacturing
process is very difficult (currently) to automate, and this has quality
control implications. For the most part this translates into extra
expense, both in fabrication and inspection/test.

The other main disadvantage is that since CFRP doesn't dent like metal,
it's very difficult to know whether impact damage has occurred.

Finally, if care is not taken at clamp points, it's easy to damage the
parts, weakening them in a non-obvious way.

In a crash, CFRP has less capacity to absorb energy since it tends to
fracture rather than deform. Opinions vary on how important this is in
real-world situations.

I think the smart way to approach CFRP purchases is on a
component-by-component basis, weighing the pro's and con's in each area.
My take is that if you really want the weight reduction and can live
with possible durability consequences (and have the bucks) CFRP frames
are OK. CFRP forks can save a lot of weight, and are probably not too
likely to get accidentally damaged (unlike a frame top tube perhaps),
crash characteristics are debatable. CFRP seatposts and bars seem not
worth the bother -- marginal weight savings, clamping/scoring
vulnerabilities, possibility of sudden brittle fracture. That goes for
most of the other smaller components, too (brake levers, stems, cranks).

CFRP rims, and now spokes, are two other areas. I haven't given too much
thought to them, but they seem a bit dubious. Given CFRP's ability to
optimize strength in a specific direction, it seems possible to make
these components with advantageous qualities, but given a wheel's
susceptibility to impact damage it might not be worth it.

Other weaknesses of CFRP are thermal, UV and solvent exposure, but these
are not likely an issue with bikes.

I have no doubt that, in the not too distant future, CFRP materials, and
especially manufacturing process enhancements, will eliminate most of
the current shortcomings, and bicycles will become virtually 100% CFRP,
highly integrated structures, ditto for virtually all vehicles. It ought
to happen, but then plastic was supposed to replace leather in shoes 40
years ago.

Peter Cole said:

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

I think the primary disadvantage of CFRP is that the manufacturing
process is very difficult (currently) to automate,

eh? look seem to be able to automate tube and lug production. the
asians use manual labor because their cost of labor is almost zero. but
you're not typically one to let detail get in the way of whatever you
want to say.

Quoted message said:

and this has quality
control implications.

yeah. metals otoh just produce themselves, no q.c. issues whatsoever.

Quoted message said:

For the most part this translates into extra
expense, both in fabrication and inspection/test.

see above.

Quoted message said:

The other main disadvantage is that since CFRP doesn't dent like metal,
it's very difficult to know whether impact damage has occurred.

just like metal. x-rayed your frame for cracks lately? as for the
great undefined peter cole ethereal "impact", do you mean "impact" like
30mm d.u. armor piercing? or "impact" like a snot ball?

Quoted message said:

Finally, if care is not taken at clamp points, it's easy to damage the
parts, weakening them in a non-obvious way.

just like thin wall metal tube.

Quoted message said:

In a crash, CFRP has less capacity to absorb energy since it tends to
fracture rather than deform. Opinions vary on how important this is in
real-world situations.

"opinions vary"??? you mean the variance among those that know what
they're talking about and those that don't? thats really going to be an
important factor in design and application!!!

<snip remaining [censored]>

bottom line, cfrp has been used in aerospace for decades, with great
success. and denial makes for endless r.b.t time wasting.

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

cT = 0.97

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

Taste varies, but pretty much all modern materials may be used to good
effect, depending on your requirements. I could quickly name shabby
examples of lousy application/execution in each material as well.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Quoted message said:

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

catzz66 said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else
in regular daily use of an ordinary city rider.

My 1953 Raleigh in daily use runs as nicely as the day it left
Nottingham. Inherently, the adhesives of a bonded bike will degrade over
a similar time span. That may have no practical effect for the bulk of
riders I admit. As always YMMV.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?

It encourages the use of acronyms.

Quoted message said:

Quoted message said:

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

catzz66 said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else
in regular daily use of an ordinary city rider.

Besides 'normal daily use' which includes UV exposure, rain, cold and
heat and the vicissitudes of scratches and dents, my 1953 steel bike's
had a few dozen minor spills and one folded crushed frame under a rental
truck in 1992. After an alignment it looks OK and rides well. In 2061
(I'll be dead) my Raleigh will still ride well. Will a ridden-daily CRFP
bike?
"Adequate" perhaps. "Durable" has many meanings.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Quoted message said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else in
regular daily use of an ordinary city rider.

My 1953 Raleigh in daily use runs as nicely as the day it left Nottingham.
Inherently, the adhesives of a bonded bike will degrade over a similar
time span. That may have no practical effect for the bulk of riders I
admit. As always YMMV.

But that has nothing to do with the fact that your bike is steel, but rather
how it was designed. If you were to construct a bike frame from carbon fiber
that weighed as much as your 1953 Raleigh, it would likely be far more
durable than what passes for armor in Iraq these days.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

"A Muzi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

For ordinary riders, carbon-fiber seems like a move toward shorter
bike life and planned obsolescence.

catzz66 said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else in
regular daily use of an ordinary city rider.

My 1953 Raleigh in daily use runs as nicely as the day it left Nottingham.
Inherently, the adhesives of a bonded bike will degrade over a similar
time span. That may have no practical effect for the bulk of riders I
admit. As always YMMV.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Mike Jacoubowsky said:

Quoted message said:

Quoted message said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else in
regular daily use of an ordinary city rider.

My 1953 Raleigh in daily use runs as nicely as the day it left Nottingham.
Inherently, the adhesives of a bonded bike will degrade over a similar
time span. That may have no practical effect for the bulk of riders I
admit. As always YMMV.

But that has nothing to do with the fact that your bike is steel, but rather
how it was designed. If you were to construct a bike frame from carbon fiber
that weighed as much as your 1953 Raleigh, it would likely be far more
durable than what passes for armor in Iraq these days.

It has rather a lot to do with the fact that it is steel. Brazing
carbonfibre-reinforced plastic is not an option; that is the difference to
which Muzi pointed as the reason he believed his frame to have lasted.

_ said:

Mike Jacoubowsky said:

Quoted message said:

> Why would you say that, Carl? If you don't anticipate bad wrecks, would
> you not think a CF road bike frame would last as long as anything else in
> regular daily use of an ordinary city rider.
My 1953 Raleigh in daily use runs as nicely as the day it left Nottingham.
Inherently, the adhesives of a bonded bike will degrade over a similar
time span. That may have no practical effect for the bulk of riders I
admit. As always YMMV.

But that has nothing to do with the fact that your bike is steel, but rather
how it was designed. If you were to construct a bike frame from carbon fiber
that weighed as much as your 1953 Raleigh, it would likely be far more
durable than what passes for armor in Iraq these days.

It has rather a lot to do with the fact that it is steel. Brazing
carbonfibre-reinforced plastic is not an option; that is the difference to
which Muzi pointed as the reason he believed his frame to have lasted.

the joining method has nothing to do with it. if the cfrp frame were as
over-built and under-stressed and spent most of its life propping up a
wall in the garage like the raleigh, it too would last a century. and
it wouldn't fatigue. and it wouldn't rust.

jim beam said:

Peter Cole said:

Quoted message said:

Anybody could tell me what is the main drawback of CFRP?
I am just steping into this field...

I think the primary disadvantage of CFRP is that the manufacturing
process is very difficult (currently) to automate,

eh? look seem to be able to automate tube and lug production.

Cites?

Quoted message said:

the
asians use manual labor because their cost of labor is almost zero.

Where does most CFRP come from?

Quoted message said:

but
you're not typically one to let detail get in the way of whatever you
want to say.

Whatever.

Quoted message said:

Quoted message said:

and this has quality
control implications.

yeah. metals otoh just produce themselves, no q.c. issues whatsoever.

Full robotic frame cut/miter, hydroform, weld. Much more repeatable.
Metal tube production -- highly automated -- ditto.

Quoted message said:

Quoted message said:

The other main disadvantage is that since CFRP doesn't dent like metal,
it's very difficult to know whether impact damage has occurred.

just like metal. x-rayed your frame for cracks lately? as for the
great undefined peter cole ethereal "impact", do you mean "impact" like
30mm d.u. armor piercing? or "impact" like a snot ball?

I mean impact like bar ends into top tube, or bike falling over against
a curb, or closing garage door on it. The usual stuff that happens to
a bike.

Quoted message said:

Quoted message said:

Finally, if care is not taken at clamp points, it's easy to damage the
parts, weakening them in a non-obvious way.

just like thin wall metal tube.

Sure, just like it, that's why you need a torque wrench.

Quoted message said:

Quoted message said:

In a crash, CFRP has less capacity to absorb energy since it tends to
fracture rather than deform. Opinions vary on how important this is in
real-world situations.

"opinions vary"??? you mean the variance among those that know what
they're talking about and those that don't? thats really going to be an
important factor in design and application!!!

Just show me the deformed CFRP & we'll put this issue to rest.

I didn't think so.

Peter Cole wrote:
<snip [censored]>

Quoted message said:

Just show me the deformed CFRP & we'll put this issue to rest.

you still don't get it. in structural applications, deformation /is/
failure. you therefore want to push deformation out along the
stress/strain graph as far as you can. that's what cfrp does. and with
better fatigue. and with lighter weight. for someone that purports to
be an "engineer", you have a pretty damned scary inability to grasp
basic fundamentals.

jim beam said:

_ said:

Mike Jacoubowsky said:

>> Why would you say that, Carl? If you don't anticipate bad wrecks,
>> would you not think a CF road bike frame would last as long as
>> anything else in regular daily use of an ordinary city rider.
> My 1953 Raleigh in daily use runs as nicely as the day it left
> Nottingham. Inherently, the adhesives of a bonded bike will degrade
> over a similar time span. That may have no practical effect for the
> bulk of riders I admit. As always YMMV.
But that has nothing to do with the fact that your bike is steel, but
rather how it was designed. If you were to construct a bike frame
from carbon fiber that weighed as much as your 1953 Raleigh, it would
likely be far more durable than what passes for armor in Iraq these
days.

It has rather a lot to do with the fact that it is steel. Brazing
carbonfibre-reinforced plastic is not an option; that is the
difference to
which Muzi pointed as the reason he believed his frame to have lasted.

the joining method has nothing to do with it. if the cfrp frame were as
over-built and under-stressed and spent most of its life propping up a
wall in the garage like the raleigh, it too would last a century. and
it wouldn't fatigue. and it wouldn't rust.

And, as long as nobody knocked it over, it wouldn't crack.

Quoted message said:

Quoted message said:

Quoted message said:

[email hidden] wrote:
> For ordinary riders, carbon-fiber seems like a move toward shorter
> bike life and planned obsolescence.

Quoted message said:

Quoted message said:

catzz66 said:

Why would you say that, Carl? If you don't anticipate bad wrecks, would
you not think a CF road bike frame would last as long as anything else in
regular daily use of an ordinary city rider.

Quoted message said:

"A Muzi" <[email hidden]> wrote

Quoted message said:

My 1953 Raleigh in daily use runs as nicely as the day it left Nottingham.
Inherently, the adhesives of a bonded bike will degrade over a similar
time span. That may have no practical effect for the bulk of riders I
admit. As always YMMV.

Mike Jacoubowsky said:

But that has nothing to do with the fact that your bike is steel, but rather
how it was designed. If you were to construct a bike frame from carbon fiber
that weighed as much as your 1953 Raleigh, it would likely be far more
durable than what passes for armor in Iraq these days.

I did note that a 50+year life for a ($29 new) bicycle may not be a
requirement for most riders.
That doesn't change the degradation of adhesives over such a time span.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971