DANGER - CARBON FIBER FRAMES

On 8/23/2016 6:00 PM, wrote:

I just got back from a 40 mile ride with 3000 feet of climbing in 39% humidity.

Those of us in the humid east are insanely jealous about 39% humidity.
I did a ten mile utility ride and lost over a pound via sweat. And it's
not even hot today.


--
- Frank Krygowski

On Tue, 23 Aug 2016 13:50:59 -0700 (PDT), wrote:

John B.

John, the failure modes for Carbon Fiber are such that using standard testing techniques do not pinpoint the sort of failures that CF is most prone to - sharp blows or sudden high frequency shocks at or above the maximum strength ratings.

Instead the testing techniques are text book - pull and push at the strength limits of the materials - this causes failures in metals but not in composites which are extremely forgiving of these sorts of loads.

You need to read up on the standards. From what I see the various
certifying tests are loads imposed in the same direction as loads
imposed in normal use.

You seem to be saying that a load imposed rapidly somehow is more
forceful than the same load imposed over a period of time?

I'm not sure that is correct. i.e., a force of, say 100 lbs. applied
for 1 hour versus the same load applied for 1 second. I think that you
are incorrect.


Composite boats are so drastically overbuilt that there isn't any chance of failure. Boats are not built for the stresses of sailing but for striking an escaped floating concrete pier section at speed.

I'm not sure what kind of boats you have been building but the ones I
am familiar are built to withstand the loads imposed on them by (1)
sailing and (2) heavy weather loadings.

And, a serious racing boat is built to loads imposed by sailing and
almost ignores any heavy weather loadings as they simply don't go out
in bad weather.

I can honestly say that I have never seen a reference to strength when
hitting a concrete pier specified as either an advantage or
disadvantage for any boat I have ever seen.

And yes, there were some very heavy composite boats build - I owned
one. Built before the strength of composites were really understood
and over built for that reason.

--
cheers,

John B.

On 24/08/16 07:27, wrote:
On Monday, August 22, 2016 at 7:06:01 PM UTC-7, James wrote:
On 23/08/16 11:17, jbeattie wrote:

Not to feed the frenzy, but CF forks are on bikes of every stripe
and in practically every price range. Old Lardy is probably
getting CF forks on his mid-fi urban bike.
http://www.trekbikes.com/us/en_US/bi...p/1330000-2016


You kind of have to hunt around for steel forks on a $700-800 bike.
Even the custom steel builders are using CF forks, although you
can spec' steel forks for an additional cost -- or you can get
them on the Soma, Surly, etc. offerings.

I ignore the hype. Just about any material that is vaguely
suitable can be built in to a reliable bicycle, provided the
bicycle is designed (engineered) and manufactured adequately.

Wood, steel, aluminium, titanium and CFRP are all fine materials to
make a bicycle frame. Each have their own advantages and
disadvantages. None stand head and shoulders above the rest.

My bicycle is made from a mix of components. The majority of the
frame is some of the thinnest walled steel tubing used to make
bicycle frames. The fork blades are CFRP, and the steerer is
aluminium. The cranks and brake levers are CFRP, while the pedals
are plastic. There are possibly some titanium bits somewhere - I
don't know, and I don't care.

Just don't buy an uber light racing machine, designed for, as Chalo
might put it, a lithe school girl, when you weigh in at twice
that.

Many racing wheels are designed to a rider weight budget, for
example. It doesn't mean the materials used to build those wheels
is bad or unreliable for general populace use, but typically that
more of the material is needed in the design to make it "average
Joe" suitable.

-- JS

Yes, however a man who claimed to be an industry insider emailed me
direct and told me that they already know the problems and that to
fix it would require that the carbon fiber bikes be made about the
same weight as Aluminum. So they are willing (presently) to trade off
weight for reliability.


Great info. If you're worried, don't buy an uber light CFRP frame and
fork. For a road bike, aim for something at least 1.2kg. Go for more if
you like. My steel frame weighs 1.7kg. My mate's Ti frame weighs
1.2kg. I suspect somewhere in between would be suitable.

Most of the people on this group are not in the play racer category
but do understand why people want the latest and greatest. But what
happens down the road when a lot of people start getting hurt? Is
"all materials wear out eventually" going to change their injuries
and feelings about them?


CFRP frames have been around for a long time already. My brother raced
in Europe on a pro continental team on one of those Alan frames where
the tubes were glued into Al lugs back in the late 80's, IIRC.

These days people usually either destroy the frame or fork in a smash,
or notice a crack in the paint, err on the side of conservative and replace.

It's not like there are hospital wards filled with people who've had a
CFRP bike suddenly disintegrate and drop them on the road. Of course
there are the odd cases, but it's not like any other materials don't fail.

--
JS

On 24/08/16 12:40, Frank Krygowski wrote:
On 8/23/2016 5:27 PM, wrote:
to be an industry insider emailed me direct and told me that they
already know the problems and that to fix it would require that the
carbon fiber bikes be made about the same weight as Aluminum. So they
are willing (presently) to trade off weight for reliability.

Most of the people on this group are not in the play racer category
but do understand why people want the latest and greatest. But what
happens down the road when a lot of people start getting hurt? Is "all
materials wear out eventually" going to change their injuries and
feelings about them?

I think it's weird that even people who are not "play racers" are
finding it hard to avoid carbon fiber forks! I'm still shopping for a
friend, but she's finding that in bikes she'd consider, most of them
above Sora level have CF forks.

Of course, the salesmen talk about the magic smoothness of the ride. I
talk about the inability to install the fenders she wants.


I was looking at some on one of the online bike shops that were
specifically for winter training bikes - to handle wider tyres and have
eyelets for "fenders" (we call mudguards).

--
JS

On Wed, 24 Aug 2016 09:29:11 +0700, John B.
wrote:

On Tue, 23 Aug 2016 06:54:14 -0700 (PDT), jbeattie
wrote:

On Tuesday, August 23, 2016 at 3:16:31 AM UTC-7, John B. wrote:
On Tue, 23 Aug 2016 09:20:10 +0700, John B.
wrote:

On Mon, 22 Aug 2016 18:17:00 -0700 (PDT), jbeattie
wrote:

On Monday, August 22, 2016 at 5:39:50 PM UTC-7, John B. wrote:
On Mon, 22 Aug 2016 09:02:50 -0700 (PDT), wrote:

On Wednesday, August 17, 2016 at 11:24:26 AM UTC-7, JLS wrote:

I looked at the photos. Looks like a glue bond failed.

JL - Colnago appears to have made three 1" forks. Their first was marked "Colnago Carbon" and had a light steel steerer tube I believe. The next was " Colnago Force Carbon" and had an aluminum steerer and finally the carbon steerer version marked "Colnago Star Carbon".

The first one appears to be much more strongly built than the others. The Force is also stout. I don't believe either of these would have failed in the same manner as the Star because they have no visible seams.

I believe there were two causes of the failure - a much lighter build of the fork through experience showing that you could get away with the lighter fork. And also the aluminum dropout is probably shorter and hence more prone to leverage failures over the shorter attachment distance.

I don't think that either of the earlier versions would have had this trouble. And the newer forks are 1 1/8th" and so a bit heftier to begin with.

But the real problem is that after analysis I have come to the conclusion that there is absolutely no way of telling if there was damage to a carbon frame or fork that could lead to catastrophic failure without warning.

While Jim Beattie is correct that ALL materials fail, the manner of these failures are generally predictable.

I would bet that if the UCI set the minimum weight of bikes in professional racing to 10 kg instead of 6.8 that all of the builders would immediately return to steel with a sigh of relief. Instead they are thinking of dropping the weight limits altogether. The lightest bikes available presently weigh less than 12 lbs.

I would suggest that if the UCI wants to drop the weight limit they set another - that ALL Tour riders are limited to ONE bike for the tour. This would mean that reliability of the bike would take a leading edge over weight.

Why should the racing authorities be interested in reliability? Are
Marathon runners restricted to one pair of shoes a year?

And who does lighter weight bikes help? ONLY the small climbers. The larger climbers aren't in the least hampered by a lb or two more.

No it helps all climbers. It is a matter of physics. No matter what, a
climber has to carry the weight of his bicycle up the mountain.

In fact, it may even mean more to Old Lard Butt then to Slim Jim as
strength is not proportional to body weight. Old Lardy who weighs 50%
more than Slim Jim doesn't produce 50% more power. It is likely to be
only 30% more power.

Not to feed the frenzy, but CF forks are on bikes of every stripe and in practically every price range. Old Lardy is probably getting CF forks on his mid-fi urban bike. http://www.trekbikes.com/us/en_US/bi...p/1330000-2016 You kind of have to hunt around for steel forks on a $700-800 bike. Even the custom steel builders are using CF forks, although you can spec' steel forks for an additional cost -- or you can get them on the Soma, Surly, etc. offerings.

-- Jay Beattie.

Just the other day one of the local bike shops that I patronize had a
bright red TREK bike in a stand, assembling it. It was the usual ugly
TREK aluminum frame with the giant, great, down tube and sort of
smooth straight forks. I asked the shop guy about it and he proudly
told me that the forks were "Kabon". I asked the price and he told me
that it was TB 35,000 (about US $1,000) but that he could get me a 20%
discount. Note that mention of a %20 discount in the initial
discussion is closer to 25 - 30 percent when the money actually
changes hands.

I even saw a folder at one of the top end shops with "Carbon" forks.

Further to the above.

I've been using Columbus tubes for some time, but Columbus also makes
Carbon fiber forks and every one I've looked at is made to meet with
EU Bicycle standards, specifically EN 14781:2005 ( I believe there is
an update to this standard)

There are various standards, EN 14764 for example covers City and
Trekking bikes, EN 14766 for Mountain Bikes, 14765 for Kids Bikes...
and EN 14781 for racing bikes.

Apparently, at least in the EU carbon forks are made to a standard so
the term "carbon forks" is essentially a meaningless term if the fork
strength or intended use is of interest.

I think it's a valid criticism of CF that when it fails, it fails catastrophically and that at least historically, it has not been very resistant to mechanical damage. Modern resins have made CF more resistant to mechanical damage and improvements in design and materials have made failures less frequent. We now have DH and big-hit bikes made of CF, and they seem to be holding up fine. But . . . if a bike has an undetected void, damage or some manufacturing defect, the consequences of a a failure could be greater than with metal.

Basically carbon fiber composites are a mix of epoxy, or a similar,
adhesive and carbon fibers. From all I read the major efforts are to
decrease the amount of epoxy in order to maximum the amount of carbon
fiber. The SCRIMP system, for example.

Carbon fiber is extremely strong in tension and negligible so in
compression thus presents certain problems in design and although I am
certain that it is possible to design and manufacture a CF fork that
would be considered virtually unbreakable in normal use it is also
likely that the fork wouldn't be acceptable to the bicycling public as
no one would be interested in buying a 700 - 800 gm CF fork.

I remember reading some time ago a comment made by one of the Italian
frame makers that they would never build a carbon fiber frame under 21
Kg. as they didn't consider it safe, which would seem to imply that
other companies were making frames under 1 Kg.

Gad! You can't trust these spelling checkers! "The under 21 Kg."
should have read "under 1 kg." :-(


My guess is an advert for "NEW! Super Carbon bike, weight 2 kg." will
attract far more attention than "NEW! Super Strong Carbon bike, weight
15 kg."
--
cheers,

John B.

On Tue, 23 Aug 2016 22:40:22 -0400, Frank Krygowski
wrote:

On 8/23/2016 5:27 PM, wrote:
to be an industry insider emailed me direct and told me that they already know the problems and that to fix it would require that the carbon fiber bikes be made about the same weight as Aluminum. So they are willing (presently) to trade off weight for reliability.

Most of the people on this group are not in the play racer category but do understand why people want the latest and greatest. But what happens down the road when a lot of people start getting hurt? Is "all materials wear out eventually" going to change their injuries and feelings about them?

I think it's weird that even people who are not "play racers" are
finding it hard to avoid carbon fiber forks! I'm still shopping for a
friend, but she's finding that in bikes she'd consider, most of them
above Sora level have CF forks.

Of course, the salesmen talk about the magic smoothness of the ride. I
talk about the inability to install the fenders she wants.

It takes about 1 lb. off the weight of the bicycle :-)

My experience is that as a general statement (except for the Muzi
Shop, of course) salesman are very interested in selling bicycles and
if a smooth ride sells bicycles then This Bike Has It!

It is probably inexperience, or maybe heresy, but I never have noticed
any difference what so ever between aluminum, Carbon or various grades
of steel, forks. I often ride different bikes over the same stretch of
road and I've never suddenly sat up as the lightening bolt strikes and
thought, "Goodness! These forks are just so much smoother!"

What I do notice is some roads are smother than others :-)

--
cheers,

John B.

On Tue, 23 Aug 2016 22:42:31 -0400, Frank Krygowski
wrote:

On 8/23/2016 6:00 PM, wrote:

I just got back from a 40 mile ride with 3000 feet of climbing in 39% humidity.

Those of us in the humid east are insanely jealous about 39% humidity.
I did a ten mile utility ride and lost over a pound via sweat. And it's
not even hot today.

The average yearly humidity here is in the very high 70's. This month,
being the rainy season, the average humidity for the month to date is
80. I did a 15 km ride this morning. at 06:00, and gained about 200
gm. after drinking some 250 gm. of water :-)
--
cheers,

John B.

James wrote:
On 24/08/16 12:40, Frank Krygowski wrote:
On 8/23/2016 5:27 PM, wrote:
to be an industry insider emailed me direct and told me that they
already know the problems and that to fix it would require that the
carbon fiber bikes be made about the same weight as Aluminum. So they
are willing (presently) to trade off weight for reliability.

Most of the people on this group are not in the play racer category
but do understand why people want the latest and greatest. But what
happens down the road when a lot of people start getting hurt? Is "all
materials wear out eventually" going to change their injuries and
feelings about them?

I think it's weird that even people who are not "play racers" are
finding it hard to avoid carbon fiber forks! I'm still shopping for a
friend, but she's finding that in bikes she'd consider, most of them
above Sora level have CF forks.

Of course, the salesmen talk about the magic smoothness of the ride. I
talk about the inability to install the fenders she wants.


I was looking at some on one of the online bike shops that were
specifically for winter training bikes - to handle wider tyres and have
eyelets for "fenders" (we call mudguards).


My Tarmac doesn't take fenders. The Roubaix does. There are choices even
on higher end bikes.

--
duane

"Duane" wrote in message ...
James wrote:
On 24/08/16 12:40, Frank Krygowski wrote:
On 8/23/2016 5:27 PM, wrote:
to be an industry insider emailed me direct and told me that they
already know the problems and that to fix it would require that the
carbon fiber bikes be made about the same weight as Aluminum. So they
are willing (presently) to trade off weight for reliability.

Most of the people on this group are not in the play racer category
but do understand why people want the latest and greatest. But what
happens down the road when a lot of people start getting hurt? Is "all
materials wear out eventually" going to change their injuries and
feelings about them?

I think it's weird that even people who are not "play racers" are
finding it hard to avoid carbon fiber forks! I'm still shopping for a
friend, but she's finding that in bikes she'd consider, most of them
above Sora level have CF forks.

Of course, the salesmen talk about the magic smoothness of the ride. I
talk about the inability to install the fenders she wants.


I was looking at some on one of the online bike shops that were
specifically for winter training bikes - to handle wider tyres and have
eyelets for "fenders" (we call mudguards).


My Tarmac doesn't take fenders. The Roubaix does. There are choices even
on higher end bikes.

--
duane

+1 My winter trainer has carbon forks designed to take mudguards and has them fitted.

Graham.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 8/24/2016 1:02 AM, John B. wrote:
On Tue, 23 Aug 2016 22:40:22 -0400, Frank Krygowski
wrote:

On 8/23/2016 5:27 PM, wrote:
to be an industry insider emailed me direct and told me that they already know the problems and that to fix it would require that the carbon fiber bikes be made about the same weight as Aluminum. So they are willing (presently) to trade off weight for reliability.

Most of the people on this group are not in the play racer category but do understand why people want the latest and greatest. But what happens down the road when a lot of people start getting hurt? Is "all materials wear out eventually" going to change their injuries and feelings about them?

I think it's weird that even people who are not "play racers" are
finding it hard to avoid carbon fiber forks! I'm still shopping for a
friend, but she's finding that in bikes she'd consider, most of them
above Sora level have CF forks.

Of course, the salesmen talk about the magic smoothness of the ride. I
talk about the inability to install the fenders she wants.

It takes about 1 lb. off the weight of the bicycle :-)

My experience is that as a general statement (except for the Muzi
Shop, of course) salesman are very interested in selling bicycles and
if a smooth ride sells bicycles then This Bike Has It!

It is probably inexperience, or maybe heresy, but I never have noticed
any difference what so ever between aluminum, Carbon or various grades
of steel, forks. I often ride different bikes over the same stretch of
road and I've never suddenly sat up as the lightening bolt strikes and
thought, "Goodness! These forks are just so much smoother!"

What I do notice is some roads are smother than others :-)


Sometimes shop owners and managers are not the root of it.
We had a successful woman selling race bikes for a couple of
years before she was overheard touting 'Reynolds Aluminum'
Holdsworths. Another bright young lady discovered that a
skimpy summer dress and heels was much more effective than
studying catalog specifications.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971