Are CF frames really safe?

On Sun, 21 May 2017 21:41:17 -0400, Frank Krygowski
wrote:

On 5/21/2017 8:46 PM, John B. wrote:
On Sun, 21 May 2017 15:32:03 -0400, Frank Krygowski
wrote:

On 5/21/2017 1:00 PM, Jeff Liebermann wrote:

No opinions on CF safety but a few comments that might be of interest.

It is very easy to demonstrate that something is unsafe. All one
needs is an anecdotal failure incident, and it becomes unsafe. The
real question is what failure rate are you willing to tolerate?

True. although in some cases you don't need an actual failure rate. If
you can imagine a failure, that sometimes suffices to label something
unsafe.

I'm on the Board of Commissioners managing a natural area owned by our
village. Some members of village council are worried about liability
from dead trees falling on people, even though the state supreme court
positively said there is no such liability regarding recreational users.

Regarding failure rate: I found a research paper that indicates the
entire U.S. has only about 12 such fatalities per year, not counting
those where a motorist runs into a fallen tree (which is impossible in
our forest). A biology professor attacked the issue from a different
direction and computed that the odds against a trail walker being hit by
a tree is up in the billions. And it goes without saying that there's
never been such an incident in the 80 year history of this forest.

But the councilman who is the big "danger!" guy heard of one incident
elsewhere in which a man sitting at a picnic table was hit by a falling
branch. So he (and the solicitor hired by the village) is commanding
that we survey all dead trees in the forest and classify them by a
"danger" ranking, then begin cutting them.

Couldn't you have either the State, or maybe Federal, Forest Service
do a survey? I vaguely remember, when I was a kid, an argument about
the value of an elm tree that the town wanted to cut and I think that
they called in some sort of "forest" guy who did some sort of study
about age, number of board feet in tree, current price of elm lumber,
etc.

But more germane, doesn't "Act of God" enter into the equation? You
elect to walk in the forest, a forest has trees, trees have limbs,
etc.?

I've consulted with two attorneys I know well. One provided me with a
state supreme court brief that in his and my view give the village
absolute protection from liability. It doesn't matter. The solicitor
gave a vague hand-waving explanation, "Yes, I've seen that brief, but I
think there may be another avenue that an injured person might be able
to use to sue the village. But I don't want to say what it is and give
them hints." And the village councilman shouted "THIS IS NOT
NEGOTIABLE! THIS IS A LIABILITY ISSUE!"

Our tax dollars at work, I guess. :-/

The U.S. never fails to amaze me. If the town puts up a sign "WARNING!
Sidewalk under repairs" and strings up a rope to keep people out, and
some one ducks under the rope and then stumbles it seems to (somehow)
be the fault of the town. Over here if the same thing happened the
stumbler" would be considered a clumsy oaf.
--
Cheers,

John B.

On Sun, 21 May 2017 21:54:47 -0700, Jeff Liebermann
wrote:

On Mon, 22 May 2017 07:26:23 +0700, John B.
wrote:

I've always wondered whether a simple "dye check" could not be used.

It can, if the paint doesn't get in the way. I've seen tubing filled
with oil or water with a phosphorescent dye added. Apply pressure and
the fluid will try to squeeze through any holes in the tubing. A UV
light might show the leak (if the paint doesn't get in the way). Don't
suggest transparent coatings instead of paint. Most clear coats block
UV but not all of them. This formulation is clear, but apparently
passes UV:
http://www.frozencpu.com/products/3854/uvp-01/Clearneon_UV_Reactive_Clear_Coat_Paint_-_Blue.html
https://www.clearneon.com


Are C.F. frames painted? Do the frames crack without disturbing the
coating, whatever it may be? Why all the folderol with phosphorescent
stuff when the conventional "dye Check" kit will show cracks and you
can pay a couple of dollars more and get the set that shows up under
ultraviolet light.

After all, it is used to inspect vehicles that thunder along 5 miles
up in the air while a bicycle runs along on the surface :-)

--
Cheers,

John B.

On 5/21/2017 11:54 PM, John B. wrote:
On Sun, 21 May 2017 21:56:39 -0400, Frank Krygowski wrote:


About failures like those shown in the links: It occurs to me that with
failed metal parts, one can often examine the fracture and get clues as
to whether the failure was sudden overload vs. long term fatigue, about
the direction of loads, etc. But AFAIK those techniques can't be used
on composite parts. Can anyone confirm that?

I can't quantify this but I believe that the inspection of composite
structures is basically an inspection of, essentially, fiber
condition, condition of the resin-fiber bonds and condition of the
resin bond - water content, etc.

I would believe that direction and severity of stress can be
determined and/or calculated but as a break in a composite is largely
a failure of the fibers I wonder whether long term fatigue figures
could be determined.

For example, a golf club shaft would be tested by flexing the shaft a
large number of times but I don't believe that there would be a change
in the material itself although it is likely that C.F. fiber might be
progressive rather then catatonic.

Common inspection methods include Ultrasonic (several different
methods), X-ray, Moisture detection, Thermography and Neutron
Radiography, all of which seem to measure density rather than
strength.

I haven't studied laminates strengths in depth but what I have read
talks about essentially fiber strengths. there are calculations that
show that once a sufficient amount of fiber breakage that breakage
then accelerates but I've seen nothing about determining degree of
broken fiber within a structure.

I have no idea whether, other then fiber breakage, repeated stress is
damaging to a composite structure. Whether "work hardening", per se,
is a property of composites.

With long term fatigue failures of metal, one can often see "beach
marks" which are sort of ripples in the fractured surface. They
generally show the direction of the fracture's gradual progression.
Sudden impact failures have a different appearance of the fracture
surface. But I'm not aware of any similar features of a CF break.


--
- Frank Krygowski

On 5/22/2017 2:39 AM, John B. wrote:
On Sun, 21 May 2017 21:54:47 -0700, Jeff Liebermann
wrote:

On Mon, 22 May 2017 07:26:23 +0700, John B.
wrote:

I've always wondered whether a simple "dye check" could not be used.

It can, if the paint doesn't get in the way. I've seen tubing filled
with oil or water with a phosphorescent dye added. Apply pressure and
the fluid will try to squeeze through any holes in the tubing. A UV
light might show the leak (if the paint doesn't get in the way). Don't
suggest transparent coatings instead of paint. Most clear coats block
UV but not all of them. This formulation is clear, but apparently
passes UV:
http://www.frozencpu.com/products/3854/uvp-01/Clearneon_UV_Reactive_Clear_Coat_Paint_-_Blue.html
https://www.clearneon.com


Are C.F. frames painted? Do the frames crack without disturbing the
coating, whatever it may be? Why all the folderol with phosphorescent
stuff when the conventional "dye Check" kit will show cracks and you
can pay a couple of dollars more and get the set that shows up under
ultraviolet light.

After all, it is used to inspect vehicles that thunder along 5 miles
up in the air while a bicycle runs along on the surface :-)


They are generally painted or at least coated in UV block
clear just like aircraft components.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sunday, May 21, 2017 at 4:25:41 PM UTC-7, AMuzi wrote:
On 5/21/2017 4:16 PM, wrote:
There is no reason for people to not buy CF except because they have a higher rate of failure than other materials. I have been riding for 40 years and have never heard of a good steel bike having a catastrophic failure. And I haven't heard of ANY aluminum bikes having catastrophic failures.

After I said that a person sent me a youtube reference of an "aluminum" frame failure. Indeed it was a catastrophic failure but it wasn't an aluminum frame but an Australian department store MTB. The entire headtube tore off the bike at the welds.

The construction appeared, from what I could see by stopping the video, to be pretty substandard. About what you would expect from K-Mart or Target. Sears and such are much better materials and techniques.

But why would there be so many videos around about CF failures and so few about other materials? Do you think that it's a conspiracy?


Jay Beattie said it correctly- everything breaks.

Please review Frame and Fork sections he
http://pardo.net/bike/pic/fail-001/000.html

extra credit:
http://www.yellowjersey.org/paint.html

Going down through the listings of failures almost none of those were catastrophic failures and the one's that were usually had damn good reasons for failure - Fox suspension forks DO NOT have both drop-outs break off. So you know that it had to be on a hard downhill and the victim getting a flat, veering off-course and hitting something damned hard.

Almost all of the steel frame failures were relatively minor plus they were on less than stellar brands. I don't consider GT (especially the older models) to be top line bikes. I don't consider bearing failures or a top end Shimano bottom bracket that had the one in a million failure by breaking off on the drive side to be anything other than a freak accident.

My brother contacted me last night since his son-in-law knows one of the local sales distributors for a major brand. The guy is trying to unload the very highest level for dealer prices or even distributor prices. Why? Not because they have a bad reputation or because they've had any failures that I know of - but because people have lost their confidence in carbon fiber. And that isn't from me talking to you people. I don't badmouth CF anywhere but here. After all, I'm trying to sell a lot of CF stuff that is really good.

On Sunday, May 21, 2017 at 4:45:50 PM UTC-7, AMuzi wrote:
On 5/21/2017 5:02 PM, wrote:
On Sunday, May 21, 2017 at 2:41:28 PM UTC-7, Jeff Liebermann wrote:
On Sun, 21 May 2017 14:16:42 -0700 (PDT), wrote:

There is no reason for people to not buy CF except because they have a higher rate of failure than other materials. I have been riding for 40 years and have never heard of a good steel bike having a catastrophic failure.. And I haven't heard of ANY aluminum bikes having catastrophic failures.

After I said that a person sent me a youtube reference of an "aluminum" frame failure. Indeed it was a catastrophic failure but it wasn't an aluminum frame but an Australian department store MTB. The entire headtube tore off the bike at the welds.

The construction appeared, from what I could see by stopping the video, to be pretty substandard. About what you would expect from K-Mart or Target. Sears and such are much better materials and techniques.

Google images usually finds some good examples:
https://www.google.com/search?q=aluminum+bicycle+frame+failure&tbm=isch
https://www.google.com/search?q=steel+bicycle+frame+failure&tbm=isch
https://www.google.com/search?q=carbon+fiber+bicycle+frame+failure&tbm=is ch
I learn quite a bit looking at failure photos.

But why would there be so many videos around about CF failures and
so few about other materials? Do you think that it's a conspiracy?

Everything is a conspiracy.

In this case, it might be that CF is considered a high price product
which would not be expected to break. CF is also far more expensive
to fix than steel or aluminum. I might also guess(tm) that
self-disassembly of a CF frame at speed might cause more expensive
injuries. Looking at the photos, the CF frames seem to come apart
breaking two or more tubes in the process, while aluminum and steel
just bend or break in one place.

Jeff - remember I was speaking of catastrophic failures. And while second grade steel and aluminum bikes indeed fail a catastrophic failure is rare. The one's pictures appear to have been at worst ALMOST catastrophic. There's a difference between "Oh**** put the brakes on" and "Hey Charlie - call an ambulance for Tom.

And as we discussed - steel and aluminum bikes in the highest quality are also those least likely to break. Whereas it is just the opposite with CF.

I'm sure that there are exceptions - I have been very impressed with the top end Giant brand. Their construction technique is superb. If you tap a vibrating fork and hold it to the frame and listen to it though the joints they all appear to be all of one piece. Many other CF bikes sound really odd in these areas. The Giants are really light without appearing to be dangerous since they increase joint strength through oversize tubing rather than adding more material to smaller tubes.

I suppose that you can make CF bikes as safe as any other material. But I don't think you can make them reasonably priced and safe at the same time, yet.

And the ride of steel is fantastic in comparison to other materials.


http://www.bustedcarbon.com/2009/12/giant-tcr.html
http://pardo.net/bike/pic/fail-001/FAIL-088.html
http://www.bustedcarbon.com/2009/07/...ance-comp.html
http://roues-aerolithe.over-blog.com...118777093.html

I have nothing against Giant and I have no idea whether
their failure rate is above or below the industry overall.

"This is what carbon looks like after hitting the side of a car"
"the failure is the result of an accident"

The third is absolutely inexplicable and is obviously a CF failure of the sort that is turning people off of CF. But that is a 2008 Giant. If you look at the previous photo of the Giant that was in the accident you can see the inflatable bladder that they NOW use in order to compress the inside of the frame so that these frames can be essentially in a mold inside and out.

But it does give me additional ammunition to think that NO CF frames will be safe under any conditions.

I am able to forgive any material for failing in a heavy enough accident. But my last fork failure was not from hitting a pothole but from hitting a sharp bump. And my fork failed almost immediately - not by falling apart but by cracking up the outside of the left leg so that the bike wouldn't steer quite right. In a left hand turn the bike drifted to the right and into the dirt and eventually into that stone culvert.

My friend was in front of my on his totally babied C40 and hit the bump first. We were travelling so fast I didn't have time to prepare for it.

Two days later he was riding with another friend up to the Golden Gate Bridge and as he got on the bridge path the entire front end fell off. Luckily it happened there and at 5 mph or so since at the other side of the bridge he would have been descending into Sausalito at 40 mph. The mind boggles.

On Sunday, May 21, 2017 at 6:59:58 PM UTC-7, Frank Krygowski wrote:
On 5/21/2017 5:16 PM, wrote:
There is no reason for people to not buy CF except because they have a higher rate of failure than other materials. I have been riding for 40 years and have never heard of a good steel bike having a catastrophic failure. And I haven't heard of ANY aluminum bikes having catastrophic failures.

Well, our good steel fork on our custom Reynolds 531 tandem failed
catastrophically. Fortunately, we were going very slow (less than 10
mph) so our bodies didn't suffer catastrophic failure. We just got
banged up a bit.

It turned out to be a case of very badly chosen fork blades, by a
builder in a hurry. I think he just used what he had on hand, rather
than proper tandem fork blades.

Then this would hardly qualify as a "good" steel bike. Tandems in particular absolutely must have proper construction as you discovered. A fork designed (especially with Reynolds tubing) for a single would hardly be appropriate for a tandem.

But of course viewing something from a historic perspective is easy.

On Sunday, May 21, 2017 at 8:54:52 PM UTC-7, John B. wrote:
On Sun, 21 May 2017 21:56:39 -0400, Frank Krygowski
wrote:

On 5/21/2017 7:45 PM, AMuzi wrote:
On 5/21/2017 5:02 PM, wrote:
On Sunday, May 21, 2017 at 2:41:28 PM UTC-7, Jeff Liebermann wrote:
On Sun, 21 May 2017 14:16:42 -0700 (PDT), wrote:

There is no reason for people to not buy CF except because they have
a higher rate of failure than other materials. I have been riding
for 40 years and have never heard of a good steel bike having a
catastrophic failure. And I haven't heard of ANY aluminum bikes
having catastrophic failures.

After I said that a person sent me a youtube reference of an
"aluminum" frame failure. Indeed it was a catastrophic failure but
it wasn't an aluminum frame but an Australian department store MTB.
The entire headtube tore off the bike at the welds.

The construction appeared, from what I could see by stopping the
video, to be pretty substandard. About what you would expect from
K-Mart or Target. Sears and such are much better materials and
techniques.

Google images usually finds some good examples:
https://www.google.com/search?q=aluminum+bicycle+frame+failure&tbm=isch

https://www.google.com/search?q=steel+bicycle+frame+failure&tbm=isch
https://www.google.com/search?q=carbon+fiber+bicycle+frame+failure&tbm=is ch

I learn quite a bit looking at failure photos.

But why would there be so many videos around about CF failures and
so few about other materials? Do you think that it's a conspiracy?

Everything is a conspiracy.

In this case, it might be that CF is considered a high price product
which would not be expected to break. CF is also far more expensive
to fix than steel or aluminum. I might also guess(tm) that
self-disassembly of a CF frame at speed might cause more expensive
injuries. Looking at the photos, the CF frames seem to come apart
breaking two or more tubes in the process, while aluminum and steel
just bend or break in one place.

Jeff - remember I was speaking of catastrophic failures. And while
second grade steel and aluminum bikes indeed fail a catastrophic
failure is rare. The one's pictures appear to have been at worst
ALMOST catastrophic. There's a difference between "Oh**** put the
brakes on" and "Hey Charlie - call an ambulance for Tom.

And as we discussed - steel and aluminum bikes in the highest quality
are also those least likely to break. Whereas it is just the opposite
with CF.

I'm sure that there are exceptions - I have been very impressed with
the top end Giant brand. Their construction technique is superb. If
you tap a vibrating fork and hold it to the frame and listen to it
though the joints they all appear to be all of one piece. Many other
CF bikes sound really odd in these areas. The Giants are really light
without appearing to be dangerous since they increase joint strength
through oversize tubing rather than adding more material to smaller
tubes.

I suppose that you can make CF bikes as safe as any other material.
But I don't think you can make them reasonably priced and safe at the
same time, yet.

And the ride of steel is fantastic in comparison to other materials.


http://www.bustedcarbon.com/2009/12/giant-tcr.html
http://pardo.net/bike/pic/fail-001/FAIL-088.html
http://www.bustedcarbon.com/2009/07/...ance-comp.html

http://roues-aerolithe.over-blog.com...118777093.html


I have nothing against Giant and I have no idea whether their failure
rate is above or below the industry overall.

About failures like those shown in the links: It occurs to me that with
failed metal parts, one can often examine the fracture and get clues as
to whether the failure was sudden overload vs. long term fatigue, about
the direction of loads, etc. But AFAIK those techniques can't be used
on composite parts. Can anyone confirm that?

I can't quantify this but I believe that the inspection of composite
structures is basically an inspection of, essentially, fiber
condition, condition of the resin-fiber bonds and condition of the
resin bond - water content, etc.

I would believe that direction and severity of stress can be
determined and/or calculated but as a break in a composite is largely
a failure of the fibers I wonder whether long term fatigue figures
could be determined.

For example, a golf club shaft would be tested by flexing the shaft a
large number of times but I don't believe that there would be a change
in the material itself although it is likely that C.F. fiber might be
progressive rather then catatonic.

Common inspection methods include Ultrasonic (several different
methods), X-ray, Moisture detection, Thermography and Neutron
Radiography, all of which seem to measure density rather than
strength.

I haven't studied laminates strengths in depth but what I have read
talks about essentially fiber strengths. there are calculations that
show that once a sufficient amount of fiber breakage that breakage
then accelerates but I've seen nothing about determining degree of
broken fiber within a structure.

I have no idea whether, other then fiber breakage, repeated stress is
damaging to a composite structure. Whether "work hardening", per se,
is a property of composites.

Andrew gave those examples of the Giant's failing. If you look at the pictures carefully you can see that the layup was faultless and that the failures were due to simply mechanical failure from building them too light.

The Giant TCR-0 of my brother's weighs 16 lbs with total DuraAce components. That's so damn light I can't even imagine riding it. And the latest one's are said to weigh 14 lbs. Other carbon fiber bikes on the market are 12 lbs.

My brother had been using a carbon fiber saddle but just like clockwork once a year they would break.

On Sunday, May 21, 2017 at 11:32:24 PM UTC-7, sms wrote:
I went to a concert tonight and one duo was playing carbon fiber cellos.

They sounded wonderful, even better than ebony cellos. They are very
expensive, and I wonder about the longevity.

https://luisandclark.com/product/cello/

One of the cheapest and best sounding Trumpets on the market is a plastic one.

On Monday, May 22, 2017 at 7:02:20 AM UTC-7, wrote:
On Sunday, May 21, 2017 at 4:45:50 PM UTC-7, AMuzi wrote:
On 5/21/2017 5:02 PM, wrote:
On Sunday, May 21, 2017 at 2:41:28 PM UTC-7, Jeff Liebermann wrote:
On Sun, 21 May 2017 14:16:42 -0700 (PDT), wrote:

There is no reason for people to not buy CF except because they have a higher rate of failure than other materials. I have been riding for 40 years and have never heard of a good steel bike having a catastrophic failure. And I haven't heard of ANY aluminum bikes having catastrophic failures.

After I said that a person sent me a youtube reference of an "aluminum" frame failure. Indeed it was a catastrophic failure but it wasn't an aluminum frame but an Australian department store MTB. The entire headtube tore off the bike at the welds.

The construction appeared, from what I could see by stopping the video, to be pretty substandard. About what you would expect from K-Mart or Target. Sears and such are much better materials and techniques.

Google images usually finds some good examples:
https://www.google.com/search?q=aluminum+bicycle+frame+failure&tbm=isch
https://www.google.com/search?q=steel+bicycle+frame+failure&tbm=isch
https://www.google.com/search?q=carbon+fiber+bicycle+frame+failure&tbm=is ch
I learn quite a bit looking at failure photos.

But why would there be so many videos around about CF failures and
so few about other materials? Do you think that it's a conspiracy?

Everything is a conspiracy.

In this case, it might be that CF is considered a high price product
which would not be expected to break. CF is also far more expensive
to fix than steel or aluminum. I might also guess(tm) that
self-disassembly of a CF frame at speed might cause more expensive
injuries. Looking at the photos, the CF frames seem to come apart
breaking two or more tubes in the process, while aluminum and steel
just bend or break in one place.

Jeff - remember I was speaking of catastrophic failures. And while second grade steel and aluminum bikes indeed fail a catastrophic failure is rare. The one's pictures appear to have been at worst ALMOST catastrophic. There's a difference between "Oh**** put the brakes on" and "Hey Charlie - call an ambulance for Tom.

And as we discussed - steel and aluminum bikes in the highest quality are also those least likely to break. Whereas it is just the opposite with CF.

I'm sure that there are exceptions - I have been very impressed with the top end Giant brand. Their construction technique is superb. If you tap a vibrating fork and hold it to the frame and listen to it though the joints they all appear to be all of one piece. Many other CF bikes sound really odd in these areas. The Giants are really light without appearing to be dangerous since they increase joint strength through oversize tubing rather than adding more material to smaller tubes.

I suppose that you can make CF bikes as safe as any other material. But I don't think you can make them reasonably priced and safe at the same time, yet.

And the ride of steel is fantastic in comparison to other materials.


http://www.bustedcarbon.com/2009/12/giant-tcr.html
http://pardo.net/bike/pic/fail-001/FAIL-088.html
http://www.bustedcarbon.com/2009/07/...ance-comp.html
http://roues-aerolithe.over-blog.com...118777093.html

I have nothing against Giant and I have no idea whether
their failure rate is above or below the industry overall.

"This is what carbon looks like after hitting the side of a car"
"the failure is the result of an accident"

The third is absolutely inexplicable and is obviously a CF failure of the sort that is turning people off of CF. But that is a 2008 Giant. If you look at the previous photo of the Giant that was in the accident you can see the inflatable bladder that they NOW use in order to compress the inside of the frame so that these frames can be essentially in a mold inside and out..

But it does give me additional ammunition to think that NO CF frames will be safe under any conditions.

I am able to forgive any material for failing in a heavy enough accident. But my last fork failure was not from hitting a pothole but from hitting a sharp bump. And my fork failed almost immediately - not by falling apart but by cracking up the outside of the left leg so that the bike wouldn't steer quite right. In a left hand turn the bike drifted to the right and into the dirt and eventually into that stone culvert.

My friend was in front of my on his totally babied C40 and hit the bump first. We were travelling so fast I didn't have time to prepare for it.

Two days later he was riding with another friend up to the Golden Gate Bridge and as he got on the bridge path the entire front end fell off. Luckily it happened there and at 5 mph or so since at the other side of the bridge he would have been descending into Sausalito at 40 mph. The mind boggles.

You're friend was on a C40? That bike was first produced in 1993-94, and its a Colnago. I'm amazed it lasted that long. With your history with Colnagos, I'm amazed you let your friend ride it at all. Those things are death traps.

I was riding my post-crash SuperSix yesterday, and it didn't break again. I do need to check the left chain stay because it got rubbed by the wheel a few years ago when the drop-out got loose (long story, a screw on the drop-out/derailleur hanger fell out), but the shop people say its fine. My worst CF problem was my shoes. Hot foot. I need some different insoles or something.

-- Jay Beattie.