Any CF experts out there?

I've been riding on some CF for 8 years now and have some questions for
any experts out there.

1. Does CF age, does the characteristics change, like does it get more
brittle, rougher riding as it ages.

2. Has CF technology changed through the years, as I have a new CF bike
that is considerably smoother than my 8 year old CF bike.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

I'm not a technical person, so a layman description would suffice.

On Sep 18, 11:14*am, Crescentius Vespasianus
wrote:
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

1. *Does CF age, does the characteristics change, like does it get more
brittle, rougher riding as it ages.

2. *Has CF technology changed through the years, as I have a new CF bike
that is considerably smoother than my 8 year old CF bike.

3. *I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

I'm not a technical person, so a layman description would suffice.

really good question, I'll be interested in the answers too- just one
thing though as it occurs to me there was an issue with bonding
techniques vs. monocoque frames, so it might help if you would relate
which 2 cf frames you are comparing

"Crescentius Vespasianus" wrote in message
...
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

1. Does CF age, does the characteristics change, like does it get more
brittle, rougher riding as it ages.

Resins do age, but the lifespan of a high-quality resin exceeds the typical
useful lifepsan of a high-quality bike (I've been told it's in the
neighborhood of a couple hundred years, providing it's treated with UV
inhibitors, which hopefully all high-quality carbon fiber bike frames are).
The adhesive is more-susceptible to UV than the resin, but is entirely
protected by the tubes themselves. Vibration is not an issue for breaking
down either the tube or adhesive with proper design.

2. Has CF technology changed through the years, as I have a new CF bike
that is considerably smoother than my 8 year old CF bike.

Carbon fiber isn't a frame, it's a material. And, like any material, you can
build something great out of it, or you can build a dog, based upon the
quality of the material and how it's used. Modern steel and aluminum frames
have improved substantially over what was available in the past; carbon
fiber is no different. What we sell today will generally ride better than
what we sold 10 years ago, and what we sell 10 years from now will likely be
better yet.

However, also like steel and aluminum, as we get more comfortable and
familiar with a material, we are more inclined to push it to its limits, so
that, just like steel, aluminum & ti frames where somebody tried to go as
light as possible, at the expense of durability, you can get the same with
carbon fiber. In other words, an off-the-shelf high end carbon fiber bike
from 10 years ago probably weighed 1 to 1.5lbs more than what you can get
now, but was stronger if you were to get hit from the side. Material is now
better-placed for the stresses of actual riding, but at the expense of
durability in either a crash or other incident that hits it hard from the
side.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

That is nonsense. The better bicycle companies have access to carbon fiber
of extraordinary quality. In Trek's case, you get carbon fiber manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of the
"best stuff" overseas, but if a company in Taiwan or China wants to build a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a bit
of expense). But the fact that Trek can ultimately get carbon fiber that's a
bit better does not prevent someone else from building an excellent bike.
The methods of laying the carbon into the molds, the temperatures and
pressures used during the curing process, and control over the exact amount
of resin used (it's cheapest to use more than needed, which results in a
less-strong frame)... those are more important than the differences between
various top grades of carbon fiber.

I'm not a technical person, so a layman description would suffice.

And that's what you're getting. I made a phone call to someone who knows a
lot more about this than I do, to confirm and add to what I knew.

Hope this helps-

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Crescentius Vespasianus wrote:

I've been riding on some CF for 8 years now and have some questions for
any experts out there.

1. *Does CF age, does the characteristics change, like does it get more
brittle, rougher riding as it ages.

Nope. The matrix can become brittle, but its modulus (intrinsic
stiffness) won't change much if any, and the matrix's properties don't
contribute significantly to tube stiffness anyway. The fibers in the
matrix should have exactly the same bulk properties as they did when
they were glued in.

2. *Has CF technology changed through the years, as I have a new CF bike
that is considerably smoother than my 8 year old CF bike.

"Smoother" is one of those terms that does not lend itself well to
quantification in units-- in fact, it's at least as often a matter of
perception as it is measurable qualities. That's why Japanese
automakers started putting in rubber bumpers for their cars' doors in
the '70s. Closing the door made it go "thump" rather than "crash"
like the Detroit hoopties of the era, and that led to a perception
that Japanese cars were more solidly built.

Carbon fiber structures, because they have a "grain", are very tunable
compared to metal frames. By changing the orientations of the fibers,
a frame can behave very differently than another frame with the same
amount of fiber in the same general locations, but different
orientations. The guiding factor has always been cost-- if you want
your carbon fibers laid just so, you have to get a skilled worker to
do it by hand. That's why the first CFRP bikes used mechanically
wound tubing pressed onto lugs; the materials properties were pretty
well understood and the manufacturing cost was manageable.

Carbon fibers have generally increased in price for some time now, but
the established base of skills and techniques has grown. Now that
CFRP manufacturing techniques are common enough for bike-specific
manufacturing companies to have their own in-house design and
production capacity, CFRP frames have become cheaper even as the
material is being used more efficiently and intentionally for
bicycles. Whether that trend is partly accountable for your
perception of ride quality differences between your two carbon-plastic
bikes is an open question. But there is no question that CFRP bikes
have become more sophisticated in their construction as their market
has grown.

It's worth noting that as CFRP bikes get more tightly tuned for the
uses they are specifically designed for, they get worse at uses they
were not specifically designed for. So if you ride CFRP, it's
becoming more important to find a bike that was specifically designed
to accommodate your body weight and luggage (if you intend to carry
any luggage).

3. *I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

Carbon fibers vary widely in strength. They vary somewhat in modulus
of elasticity. For higher performance fiber, you pay more. So the
design objective is always to do the job with the cheapest fiber that
will do it, unless that means increasing the cost of labor even
more.

Chalo

In article ,
Crescentius Vespasianus wrote:

I've been riding on some CF for 8 years now and have some questions for
any experts out there.

1. Does CF age, does the characteristics change, like does it get more
brittle, rougher riding as it ages.

2. Has CF technology changed through the years, as I have a new CF bike
that is considerably smoother than my 8 year old CF bike.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

I'm not a technical person, so a layman description would suffice.

Does fiberglass/resin age? Typically no, and the same for
carbon fiber/resin. The resin is formulated to resist
chemical attack, and being a cross-linked polymer this
is relatively easy. The long term risks for cf/r are
scratching and delamination. Carbon fiber in aircraft is
watched very closely.

--
Michael Press

In article ,
Crescentius Vespasianus wrote:

I've been riding on some CF for 8 years now and have some questions
for any experts out there.

1. Does CF age, does the characteristics change, like does it get
more brittle, rougher riding as it ages.

There have been doubts cast upon whether CF is affected by UV radiation
and may embrittle over time, but I am not aware of any proof that this
happens in the normal usage of bicycles. Maybe someone else will know
of evidence that this happens.

In terms of rougher riding, this sounds like the old myths about steel
frames getting soft over the course of a few years. That doesn't happen
and I'd be astonished if CF got stiffer and gave a rougher ride with
time- and, even if it did, that the difference would be detectable given
the triangulated structure of a bicycle frame.

I think the signal problem with CF is its impact resistance. That's
already been discussed to death. In any event we don't see thousands of
reports of CF frames disintegrating as people are riding along.

2. Has CF technology changed through the years, as I have a new CF
bike that is considerably smoother than my 8 year old CF bike.

"Smoother" in terms of the frame is due to geometry first and foremost.
There's some measurements which suggest that "rigid" forks may absorb
some shock through small deflection excursions, but I didn't think that
the article I read was as definitive as its authors thought (Bicycle
Quarterly, 6, 3, pp. 24-29). At best the effect is very small.

3. I once read here in rbt that the aircraft industry gets the best
CF and the bike industry uses the crap CF, is there a difference in
the quality of CF?

Given the risks of lawsuits and the like, I find it hard to believe that
companies like Trek, Giant, etc. would use inferior materials to build
their bikes. With something as complex as CF construction, "the best"
is difficult to define. "The best for a given application" might be
somewhat easier to define.

I'm not a technical person, so a layman description would suffice.

In article ,
"Mike Jacoubowsky" wrote:

"Crescentius Vespasianus" wrote in message
...
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

That is nonsense. The better bicycle companies have access to carbon fiber
of extraordinary quality. In Trek's case, you get carbon fiber manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of the
"best stuff" overseas, but if a company in Taiwan or China wants to build a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a bit
of expense). But the fact that Trek can ultimately get carbon fiber that's a
bit better does not prevent someone else from building an excellent bike.

Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On Sep 18, 5:59*pm, Ryan Cousineau wrote:
In article ,
*"Mike Jacoubowsky" wrote:



"Crescentius Vespasianus" wrote in message
...
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

3. *I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

That is nonsense. The better bicycle companies have access to carbon fiber
of extraordinary quality. In Trek's case, you get carbon fiber manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of the
"best stuff" overseas, but if a company in Taiwan or China wants to build a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a bit
of expense). But the fact that Trek can ultimately get carbon fiber that's a
bit better does not prevent someone else from building an excellent bike.

Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

These technological answers are beside the point.
The OP's new bike feels and rides better than his
eight year old bike because it is new. No amount
of age-testing of CF resins and layups will ever dent
this effect.

Ryan, don't even start asking someone to explain
ITAR restriction to you. ITAR is the Chewbacca
Defense of international commerce. Somewhere,
there is a kernel of truth underneath each: it does
not make sense that a wookie lives on Endor, and
there are technologies that the US should actually
avoid exporting freely to avoid their transmission
to scary people. However, over these kernels of sense
are grown layers and layers of chewy peel of
incomprehensible confusion. The Chewbacca
Defense you know, and as for ITAR ... well, read
the example about freezing plasticized tape in
this article:

http://seattletimes.nwsource.com/htm...esstechnology/
2002754224_boeingitar22.html

Ben

That is nonsense. The better bicycle companies have access to carbon
fiber
of extraordinary quality. In Trek's case, you get carbon fiber
manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of
the
"best stuff" overseas, but if a company in Taiwan or China wants to build
a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a
bit
of expense). But the fact that Trek can ultimately get carbon fiber
that's a
bit better does not prevent someone else from building an excellent bike.

Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

Trek can export a frame made of the restricted material, but there are
restrictions on the export of the material itself. Don't ask me how or why.
My guess is that it's done more to protect the domestic aircraft industry
than to keep dangerous technology out of China. And, as I said, it's not as
if Giant or whomever can't get high-quality carbon fiber. But Trek does
benefit from having relationships with companies that can freely demonstrate
and sell their coolest & greatest stuff, even though it might not go into a
bicycle anytime soon. The advantage is that Trek sees where things are going
and what materials might be practical (and cost-effective) to use down the
road.

Last time I was in Wisconsin (August) I saw some of this super-duper
material. Looks like any other to me, except that it feels much less
substantial (because there's less of it per square meter). An engineer
explained the benefits and drawbacks to its use, and how it makes sense to
use in some areas of a frame, and not in others. Someday that stuff will
come down in price and be available anywhere, and at that point somebody is
going to build a ridiculously-light frame out of it that will be fine as
long as you're upright, but if you hit the top tube with your shoe as you're
putting a leg over it, you'll probably crack it. That's where it seems we're
going. Hopefully we'll get to the point where people will understand the
trade-offs and there will be a market for essentially the same bike in two
different versions- one which is built as light as you can and still survive
the rigors of racing, but if it falls against a coffee table, it might break
in half. And the other might weigh half a pound, maybe 3/4 pound more, same
ride quality, but be much more durable against accidental damage.

We're not there yet. Right now, the customer wanting to buy a $6000+ bike
wants it to be as light as possible. It's an education thing. Nobody is
going to tell that customer that he or she is giving something up by doing
so, because they don't want to scare customers away to their competitors
(who won't be saying that and thus it will be assumed their bikes are
better). But if a manufacturer takes the not-so-bold step of doing two
different high-end frames, one bleeding edge, the other just slightly
heavier and more durable... I think people are smart enough to make a
reasonable choice, and a good number will choose the slightly-heavier bike.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA



"Ryan Cousineau" wrote in message
]...
In article ,
"Mike Jacoubowsky" wrote:

"Crescentius Vespasianus" wrote in message
...
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?

That is nonsense. The better bicycle companies have access to carbon
fiber
of extraordinary quality. In Trek's case, you get carbon fiber
manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of
the
"best stuff" overseas, but if a company in Taiwan or China wants to build
a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a
bit
of expense). But the fact that Trek can ultimately get carbon fiber
that's a
bit better does not prevent someone else from building an excellent bike.

Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

Mike Jacoubowsky wrote:
That is nonsense. The better bicycle companies have access to carbon
fiber
of extraordinary quality. In Trek's case, you get carbon fiber
manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of
the
"best stuff" overseas, but if a company in Taiwan or China wants to build
a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a
bit
of expense). But the fact that Trek can ultimately get carbon fiber
that's a
bit better does not prevent someone else from building an excellent bike.
Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

Trek can export a frame made of the restricted material, but there are
restrictions on the export of the material itself. Don't ask me how or why.
My guess is that it's done more to protect the domestic aircraft industry
than to keep dangerous technology out of China. And, as I said, it's not as
if Giant or whomever can't get high-quality carbon fiber. But Trek does
benefit from having relationships with companies that can freely demonstrate
and sell their coolest & greatest stuff, even though it might not go into a
bicycle anytime soon. The advantage is that Trek sees where things are going
and what materials might be practical (and cost-effective) to use down the
road.

Last time I was in Wisconsin (August) I saw some of this super-duper
material. Looks like any other to me, except that it feels much less
substantial (because there's less of it per square meter). An engineer
explained the benefits and drawbacks to its use, and how it makes sense to
use in some areas of a frame, and not in others. Someday that stuff will
come down in price and be available anywhere, and at that point somebody is
going to build a ridiculously-light frame out of it that will be fine as
long as you're upright, but if you hit the top tube with your shoe as you're
putting a leg over it, you'll probably crack it. That's where it seems we're
going. Hopefully we'll get to the point where people will understand the
trade-offs and there will be a market for essentially the same bike in two
different versions- one which is built as light as you can and still survive
the rigors of racing, but if it falls against a coffee table, it might break
in half. And the other might weigh half a pound, maybe 3/4 pound more, same
ride quality, but be much more durable against accidental damage.

We're not there yet. Right now, the customer wanting to buy a $6000+ bike
wants it to be as light as possible. It's an education thing. Nobody is
going to tell that customer that he or she is giving something up by doing
so, because they don't want to scare customers away to their competitors
(who won't be saying that and thus it will be assumed their bikes are
better). But if a manufacturer takes the not-so-bold step of doing two
different high-end frames, one bleeding edge, the other just slightly
heavier and more durable... I think people are smart enough to make a
reasonable choice, and a good number will choose the slightly-heavier bike.

look already do that with their high end frames - two versions of the
same design, eg. "585" and "585 ultra".




--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA



"Ryan Cousineau" wrote in message
]...
In article ,
"Mike Jacoubowsky" wrote:

"Crescentius Vespasianus" wrote in message
...
I've been riding on some CF for 8 years now and have some questions for
any experts out there.

3. I once read here in rbt that the aircraft industry gets the best CF
and the bike industry uses the crap CF, is there a difference in the
quality of CF?
That is nonsense. The better bicycle companies have access to carbon
fiber
of extraordinary quality. In Trek's case, you get carbon fiber
manufacturers
that want to show off their best stuff because they're a high-visibility
domestic manufacturer. There are export laws that prohibit the sale of
the
"best stuff" overseas, but if a company in Taiwan or China wants to build
a
very high quality frame, they can get material that's certainly very high
quality. Whether they want to is another thing entirely (it adds quite a
bit
of expense). But the fact that Trek can ultimately get carbon fiber
that's a
bit better does not prevent someone else from building an excellent bike.
Okay Mike, don't take this question the wrong way, but which Trek frames
are unexportable due to their magic materials?

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."