Should I be afraid of carbon?



DeanC

New Member
Aug 5, 2004
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So I'm recently back into riding my road bike after not riding seriously for 10 years or so. I've given myself a carrot in that I've said I'll replace my '89 Bianchi Limited with something modern after I put 1000 more miles on it. Of course, that means I get to start shopping for a new bike... :D

At 250lbs I'm pretty big for a bicyclist and even when I'm done dropping the excess fat I'm trying to I'm still gonna be 210lbs or so, so stiff and durable has a higher relative value vs. weight than it would if I was 145lbs. I know that steel frames that can survive me climbing out of the saddle exist, my Bianchi does it today and I know AL can do it too. But I just don't know enough about carbon...

I've seen a bunch of FUD about carbon forks (even seen one custom frame builder that refuses to use them because he believes they're unsafe) and I've seen several people post things in this forum about carbon frames not being able to survive crashes but it looks like Trek is still selling them... What's the real scoop here? Is there such a thing as a carbon bike that would survive 10 years of a >200lb guy riding it or should I limit my search to metals?

Thanks,
Dean
 
"DeanC" <[email protected]> wrote in message
news:D[email protected]...
>
> So I'm recently back into riding my road bike after not riding seriously
> for 10 years or so. I've given myself a carrot in that I've said I'll
> replace my '89 Bianchi Limited with something modern after I put 1000
> more miles on it. Of course, that means I get to start shopping for a
> new bike... :D
>
> At 250lbs I'm pretty big for a bicyclist and even when I'm done
> dropping the excess fat I'm trying to I'm still gonna be 210lbs or so,
> so stiff and durable has a higher relative value vs. weight than it
> would if I was 145lbs. I know that steel frames that can survive me
> climbing out of the saddle exist, my Bianchi does it today and I know
> AL can do it too. But I just don't know enough about carbon...
>
> I've seen a bunch of FUD about carbon forks (even seen one custom frame
> builder that refuses to use them because he believes they're unsafe) and
> I've seen several people post things in this forum about carbon frames
> not being able to survive crashes but it looks like Trek is still
> selling them... What's the real scoop here? Is there such a thing as
> a carbon bike that would survive 10 years of a >200lb guy riding it or
> should I limit my search to metals?
>
> Thanks,
> Dean
>


I can only speak about my Trek 5500. I'm on my third one 'cuz the first two
got toasted by cars (and me along with them). But up until that point, they
each had about 35,000 miles or better on them and they were doing just fine.
I "only" weigh 155 or so, but I have plenty of larger friends who ride Trek
OCLV. I've always stuck with the 5500 which uses a heavier carbon layup.
Many of the new Treks are reducing the carbon content to lighten the bikes.
I'm sure that's fine for the pros who use them for a season. I suspect it's
not fine for my 35,000 then a car wreck routine. I was reading recently
about an awesome new carbon frame from Scott. It's awesome in its ride
characteristics and its incredible lightness. But the review I read said
that the kid down at the local bike shop could easily crush one off the
tubes putting it in a work stand. No thanks. A basic Trek OCLV frame like
the current crop of 5200s or 5500s is pretty bomb-proof. And they're still
light, high-peformance bikes. Note that Trek is dropping the 5200/5500 OCLV
frame in its current configuration in 2005. You'll have to do your own
homework on the replacement models.

Good luck.

Bob C.
 
On Wed, 25 Aug 2004 08:30:21 +1000, DeanC wrote:

>
> So I'm recently back into riding my road bike after not riding seriously
> for 10 years or so.


Welcome back. I been there, too.

> At 250lbs I'm pretty big for a bicyclist and even when I'm done
> dropping the excess fat I'm trying to I'm still gonna be 210lbs or so,
> so stiff and durable has a higher relative value vs. weight than it
> would if I was 145lbs. I know that steel frames that can survive me
> climbing out of the saddle exist, my Bianchi does it today and I know
> AL can do it too. But I just don't know enough about carbon...
>
> I've seen a bunch of FUD about carbon forks (even seen one custom frame
> builder that refuses to use them because he believes they're unsafe)


Ah, balderdash. Carbon forks are so common now that, if they were a
serious hazard, you'd know about it. But they aren't. I'm a bit lighter
than you, but still at 200lbs I have no problem with my carbon fork. We
have a carbon fork on the tandem, too.

Carbon bikes? Well, people have a lot of experience with them, too.
Personally, I prefer titanium.

--

David L. Johnson

__o | Let's not escape into mathematics. Let's stay with reality. --
_`\(,_ | Michael Crichton
(_)/ (_) |
 
I am in the 250 to 270 range.....I have an all carbon rig...


the key...don't buy cheap stuff and look for a good warrantee as well as a
name behind it..

I like my carbon stuff.....

Biff Stephens


"David L. Johnson" <[email protected]> wrote in message
news:p[email protected]...
> On Wed, 25 Aug 2004 08:30:21 +1000, DeanC wrote:
>
> >
> > So I'm recently back into riding my road bike after not riding seriously
> > for 10 years or so.

>
> Welcome back. I been there, too.
>
> > At 250lbs I'm pretty big for a bicyclist and even when I'm done
> > dropping the excess fat I'm trying to I'm still gonna be 210lbs or so,
> > so stiff and durable has a higher relative value vs. weight than it
> > would if I was 145lbs. I know that steel frames that can survive me
> > climbing out of the saddle exist, my Bianchi does it today and I know
> > AL can do it too. But I just don't know enough about carbon...
> >
> > I've seen a bunch of FUD about carbon forks (even seen one custom frame
> > builder that refuses to use them because he believes they're unsafe)

>
> Ah, balderdash. Carbon forks are so common now that, if they were a
> serious hazard, you'd know about it. But they aren't. I'm a bit lighter
> than you, but still at 200lbs I have no problem with my carbon fork. We
> have a carbon fork on the tandem, too.
>
> Carbon bikes? Well, people have a lot of experience with them, too.
> Personally, I prefer titanium.
>
> --
>
> David L. Johnson
>
> __o | Let's not escape into mathematics. Let's stay with reality. --
> _`\(,_ | Michael Crichton
> (_)/ (_) |
>
>
 
On Wed, 25 Aug 2004 08:30:21 +1000, DeanC
<[email protected]> wrote:

>... What's the real scoop here? Is there such a thing as
>a carbon bike that would survive 10 years of a >200lb guy riding it or
>should I limit my search to metals?


Well, metal frames have a lot more history behind them, and carbon's
usually (but not always) easier to break and more susceptible to being
damaged by somebody that shouldn't have been fiddling with the bike to
begin with, but the majority of the evidence is that a well-built
carbon frame, properly handled, is plenty strong and plenty durable.
Forks? It's a mixed bag. There are certainly some very good, very
stiff (and incredibly light) units available, but for the difference
in price vs the difference in weight (which is the only difference
that *should* be present from a practical standpoint), I'd stay with
the metal forks just because they'll do the job for a lot less money.

From my personal standpoint, I favor metal. That's mostly because I'm
a cheapskate, but I think I'd probably still favor metal if I had the
bucks, simply because I also know that I'm never going to be enough of
an athlete for the small difference in weight savings of a carbon
frame or fork to have any effect on my riding.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
I'm actually on the market right now for a new fork for my bike. It looks
like I'll probably end up eliminating carbon from my list of choices. A
lot of them have to do with my own personal preferences and what I'm
looking for in my ride but I tend to be biased against carbon materials.
If I was gonna be on a machine that I could throw away after a season
and had my own personal (and very careful) mechanic I might go with
carbon fiber components/frame.

I tend to feel that ultimately the manufacturer makes a lot of
assumptions about how the consumer will use the carbon product. Since
the manufactuer is correct (for the most part) about what the consumer
will do and encounter as they ride, parts and frames tend to stay
intact. It's the consumer that happens into the odd situation or two
(or who just doesn't follow the rules) that tends to get into trouble.
All of that seems fair enough for the most part.

There are, however, two issues I have that keep me from slapping that
black stuff on every square inch of my bike

1. Carbon's tendency for *catastrophic* failure (yes I know Al has
a similar property but see point #2)

2. Carbon's inferior tolerance for humans to be humans (i.e. when
the ineveitable happens, carbon will cry uncle before non-carbon
materials, generally speaking)

I appreciate it as a material for what it's worth but I prefer to keep
it to a minimum on *my* bikes, even the ones that I race.




D. Ualp
 
DeanC <[email protected]> wrote in message news:<[email protected]>...
> So I'm recently back into riding my road bike after not riding seriously
> for 10 years or so. I've given myself a carrot in that I've said I'll
> replace my '89 Bianchi Limited with something modern after I put 1000
> more miles on it. Of course, that means I get to start shopping for a
> new bike... :D
>
> At 250lbs I'm pretty big for a bicyclist and even when I'm done
> dropping the excess fat I'm trying to I'm still gonna be 210lbs or so,
> so stiff and durable has a higher relative value vs. weight than it
> would if I was 145lbs. I know that steel frames that can survive me
> climbing out of the saddle exist, my Bianchi does it today and I know
> AL can do it too. But I just don't know enough about carbon...
>
> I've seen a bunch of FUD about carbon forks (even seen one custom frame
> builder that refuses to use them because he believes they're unsafe) and
> I've seen several people post things in this forum about carbon frames
> not being able to survive crashes but it looks like Trek is still
> selling them... What's the real scoop here? Is there such a thing as
> a carbon bike that would survive 10 years of a >200lb guy riding it or
> should I limit my search to metals?
>
> Thanks,
> Dean


I am >200lb and have been riding a Trek 2120 (carbon main tubes) for
10 years with no trouble whatsoever, and in my area I see a good
number of older OCLV models out on the roads. The current generation
of carbon frames are much m stiffer and stronger than my frame, so I
find it hard to believe that they would lack durability. Can't say
whether carbon is better or worse than other materials re. surviving
crashes, but having just crashed mine (it survived) I would strongly
advise you not to crash. It hurts.
 
Dean-<< What's the real scoop here? Is there such a thing as
a carbon bike that would survive 10 years of a >200lb guy riding it or
should I limit my search to metals? >><BR><BR>

http://www.calfeedesign.com

I have a Luna that I expect will last longer than I do.

I'm .1 off a ton and past the .5 century mark.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
 
DeanC <[email protected]> wrote:

> At 250lbs I'm pretty big for a bicyclist and even when I'm done
> dropping the excess fat I'm trying to I'm still gonna be 210lbs or so,
> so stiff and durable has a higher relative value vs. weight than it
> would if I was 145lbs. I know that steel frames that can survive me
> climbing out of the saddle exist, my Bianchi does it today and I know
> AL can do it too. But I just don't know enough about carbon...


Competently designed and manufactured CFRP components have a greater
structural safety margin than metal components. The reason for this
is simple: Carbon fiber composites do not bend, but can only break
when they fail.

If you seldom or never bend or break metal parts, then you don't have
much to worry about. If, like me, you can bend or break pretty much
any bike part, then you're probably better off with metal components
and sturdy ones at that.

The only other circumstances under which I would avoid CFRP parts
would be for commuting, courier work, or other duty that leaves
scratches, paint chips, or dents on a metal bike. Superficial damage
of this sort is unlikely to cause failure of a metal bike, but
somewhat likely to propagate breakage in a CFRP structure.

Think of CFRP as a kind of paint, one that uses carbon fiber mixed
into the resin instead of pigment. If your metal bikes keep
sharp-looking paint, then CFRP will do fine in the same circumstances.

Chalo Colina
 
WTD wrote in message <[email protected]>...
>I am >200lb and have been riding a Trek 2120 (carbon main tubes) for
>10 years with no trouble whatsoever, and in my area I see a good
>number of older OCLV models out on the roads. The current generation
>of carbon frames are much m stiffer and stronger than my frame, so I
>find it hard to believe that they would lack durability. Can't say
>whether carbon is better or worse than other materials re. surviving
>crashes, but having just crashed mine (it survived) I would strongly
>advise you not to crash. It hurts.


Should the frame snap, could you be skewered with the fractured carbon?

Trevor
 
[email protected] (Qui si parla Campagnolo ) wrote;
>
> Dean-<< What's the real scoop here? Is there such a thing as
> a carbon bike that would survive 10 years of a >200lb guy riding it? >><BR><BR>
>
> http://www.calfeedesign.com
>
> I have a Luna that I expect will last longer than I do.


I wonder if folks aren't ignoring the fact that the other ingredient
in "carbon" is epoxy resin. I have not encountered a plastic material
that maintains its strength and flexibility over time, and that's
especially true of epoxy. It seems to get much more brittle over a
span of years.

I imagine that the resin blends and curing processes for industrially
produced frames and forks are highly controlled for reliable results,
but the same could probably be said for old plastic combs,
kitchenware, buckets, and many other plastic products that we can
observe becoming weak and brittle as they reach "adulthood".

Some resins seem to maintain their toughness well, like phenolic and
polycarbonate, while others embrittle relatively quickly, like
polyethylene and styrene. Epoxy seems to be in the latter category
according to my experience.

I have no experience with old polyester/glass boats or car bodywork;
do these things maintain their integrity as they age? From the look
of all those embedded-object tables that were trendy in the '70s,
polyester resin holds up better than epoxy over time, though. '50s
boat hulls or car fenders may not be the best indicator for the
longevity of CFRP structures.

How about old G10 circuit boards? They are epoxy-based and at least
as carefully standardized as bike parts. Are 30-year old circuit
boards similar in strength and resilience to new ones? If they hold
up over time, my guess is that CFRP bike frams and forks should do
about the same, given tight initial quality control.

Chalo Colina
 
"Chalo" <[email protected]> wrote in message
news:[email protected]...
>

snip
> How about old G10 circuit boards? They are epoxy-based and at least
> as carefully standardized as bike parts. Are 30-year old circuit
> boards similar in strength and resilience to new ones? If they hold
> up over time, my guess is that CFRP bike frams and forks should do
> about the same, given tight initial quality control.
>
> Chalo Colina

The 30 year old board sitting in the box of junk next to my desk looks and
flexes like the day it was made, at least at a cursory inspection level.

del cecchi
 
On 25 Aug 2004 14:30:24 -0700, [email protected]
(Chalo) wrote:

>[email protected] (Qui si parla Campagnolo ) wrote;
>>
>> Dean-<< What's the real scoop here? Is there such a thing as
>> a carbon bike that would survive 10 years of a >200lb guy riding it? >><BR><BR>
>>
>> http://www.calfeedesign.com
>>
>> I have a Luna that I expect will last longer than I do.

>
>I wonder if folks aren't ignoring the fact that the other ingredient
>in "carbon" is epoxy resin. I have not encountered a plastic material
>that maintains its strength and flexibility over time, and that's
>especially true of epoxy. It seems to get much more brittle over a
>span of years.
>
>I imagine that the resin blends and curing processes for industrially
>produced frames and forks are highly controlled for reliable results,
>but the same could probably be said for old plastic combs,
>kitchenware, buckets, and many other plastic products that we can
>observe becoming weak and brittle as they reach "adulthood".
>
>Some resins seem to maintain their toughness well, like phenolic and
>polycarbonate, while others embrittle relatively quickly, like
>polyethylene and styrene. Epoxy seems to be in the latter category
>according to my experience.
>
>I have no experience with old polyester/glass boats or car bodywork;
>do these things maintain their integrity as they age? From the look
>of all those embedded-object tables that were trendy in the '70s,
>polyester resin holds up better than epoxy over time, though. '50s
>boat hulls or car fenders may not be the best indicator for the
>longevity of CFRP structures.
>
>How about old G10 circuit boards? They are epoxy-based and at least
>as carefully standardized as bike parts. Are 30-year old circuit
>boards similar in strength and resilience to new ones? If they hold
>up over time, my guess is that CFRP bike frams and forks should do
>about the same, given tight initial quality control.
>
>Chalo Colina


Dear Chalo,

One possible complication is that circuit boards, unlike
bike frames, are affected by lots of local hot spots.

Carl Fogel
 
On 25 Aug 2004 14:30:24 -0700, [email protected] (Chalo) wrote:

>I have no experience with old polyester/glass boats or car bodywork;
>do these things maintain their integrity as they age?


There is a tendency for polyester resin that's exposed to UV to
deteriorate and craze if not kept painted, in my experience, but
early-'60s Corvettes with no repairs do exist. There was a graveyard
of fiberglass boats of varying ages near here until recently, full of
hulls that had been holed. Some of them dated from the mid-'70s. In
most cases, the materials were sound but the gross damage made the
hulls uneconomical to repair. That's not epoxy, though. Most
resin/fiber vehicle parts aren't, as you noted.

>From the look
>of all those embedded-object tables that were trendy in the '70s,
>polyester resin holds up better than epoxy over time, though. '50s
>boat hulls or car fenders may not be the best indicator for the
>longevity of CFRP structures.


Some epoxies certainly do hold up well; I have a couple of items here
which were bonded in 1978 and are still holding strong. Of course,
those are glued joints in items that present very little of the
material to the external environment; not a good indicator of their
potential in the requested context. (And those were bonded with
aviation-grade epoxies, not the junk they sell at Radio Shack.)

>How about old G10 circuit boards? They are epoxy-based and at least
>as carefully standardized as bike parts. Are 30-year old circuit
>boards similar in strength and resilience to new ones? If they hold
>up over time, my guess is that CFRP bike frams and forks should do
>about the same, given tight initial quality control.


Now, that one I can say is probably the case. I recently chucked a
number of mid-'70s PCBs into the recycling bin when cleaning out a
storage bay; they seemed not to be brittle and were not crazed.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
On Wed, 25 Aug 2004 16:00:23 -0600, [email protected] wrote:

>One possible complication is that circuit boards, unlike
>bike frames, are affected by lots of local hot spots.


Some are also exposed to significant levels of ozone, and yet seem
unaffected.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
Chalo wrote in message <[email protected]>...
>
>I wonder if folks aren't ignoring the fact that the other ingredient
>in "carbon" is epoxy resin. I have not encountered a plastic material
>that maintains its strength and flexibility over time, and that's
>especially true of epoxy. It seems to get much more brittle over a
>span of years.
>
>I imagine that the resin blends and curing processes for industrially
>produced frames and forks are highly controlled for reliable results,
>but the same could probably be said for old plastic combs,
>kitchenware, buckets, and many other plastic products that we can
>observe becoming weak and brittle as they reach "adulthood".
>
>Some resins seem to maintain their toughness well, like phenolic and
>polycarbonate, while others embrittle relatively quickly, like
>polyethylene and styrene. Epoxy seems to be in the latter category
>according to my experience.
>
>I have no experience with old polyester/glass boats or car bodywork;
>do these things maintain their integrity as they age? From the look
>of all those embedded-object tables that were trendy in the '70s,
>polyester resin holds up better than epoxy over time, though. '50s
>boat hulls or car fenders may not be the best indicator for the
>longevity of CFRP structures.
>
>How about old G10 circuit boards? They are epoxy-based and at least
>as carefully standardized as bike parts. Are 30-year old circuit
>boards similar in strength and resilience to new ones? If they hold
>up over time, my guess is that CFRP bike frams and forks should do
>about the same, given tight initial quality control.
>


Resin impregnated boats have deteriorated due to environmental effects,
presumed to be UV instability. Modern incarnations use a UV blocking gel
coat to protect the underlying resin.

Circuit board use epoxy solely as an adhesive and not as a filler. The
comparison is not particularly relevant because it is mostly the pressure
that binds the paper, glass and epoxy together and very little epoxy is
used. Circuit board are not generally subjected to UV light.

Trevor


Trevor
 
On Wed, 25 Aug 2004 14:30:24 -0700, Chalo wrote:

> I wonder if folks aren't ignoring the fact that the other ingredient
> in "carbon" is epoxy resin. I have not encountered a plastic material
> that maintains its strength and flexibility over time, and that's
> especially true of epoxy. It seems to get much more brittle over a
> span of years.


> Some resins seem to maintain their toughness well, like phenolic and
> polycarbonate, while others embrittle relatively quickly, like
> polyethylene and styrene. Epoxy seems to be in the latter category
> according to my experience.


there a a lot of fiberglass boats out there that have had much more
significant exposure than any bike would get in a lifetime, with no
trouble. The resin is the same class as in CF bike parts.

--

David L. Johnson

__o | A mathematician is a machine for turning coffee into theorems.
_`\(,_ | -- Paul Erdos
(_)/ (_) |
 
Werehatrack <[email protected]> wrote:
>
> [email protected] wrote:
> >
> >One possible complication is that circuit boards, unlike
> >bike frames, are affected by lots of local hot spots.

>
> Some are also exposed to significant levels of ozone, and yet seem
> unaffected.


Another variable is UV radiation, which bikes get a lot of while
circuit boards generally don't.

Chalo Colina
 
Chalo wrote:
> Werehatrack <[email protected]> wrote:
>
>>[email protected] wrote:
>>
>>>One possible complication is that circuit boards, unlike
>>>bike frames, are affected by lots of local hot spots.

>>
>>Some are also exposed to significant levels of ozone, and yet seem
>>unaffected.

>
>
> Another variable is UV radiation, which bikes get a lot of while
> circuit boards generally don't.


Who rides an unpainted bicycle? And if UV radiation is a problem, it is
a simple matter to block it with a coating.
 
David L. Johnson wrote in message ...
>On Wed, 25 Aug 2004 14:30:24 -0700, Chalo wrote:
>
>> I wonder if folks aren't ignoring the fact that the other ingredient
>> in "carbon" is epoxy resin. I have not encountered a plastic material
>> that maintains its strength and flexibility over time, and that's
>> especially true of epoxy. It seems to get much more brittle over a
>> span of years.

>
>> Some resins seem to maintain their toughness well, like phenolic and
>> polycarbonate, while others embrittle relatively quickly, like
>> polyethylene and styrene. Epoxy seems to be in the latter category
>> according to my experience.

>
>there a a lot of fiberglass boats out there that have had much more
>significant exposure than any bike would get in a lifetime, with no
>trouble. The resin is the same class as in CF bike parts.
>
>--

Stresses made upon a boat hull are much different than that made upon a
bicycle frame.

Trevor
 

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