"brittle" vs. non-ductile

[Mike Jacoubowsky]

Chalo: I'm not going to go into everything in your reply point-by-point,
because, for the most part, I agree!!!

Carbon fiber isn't the ideal material for all kinds of bikes. I never
suggested it was. Why spend a fortune for a bike that's going to get
seriously dinged up in normal use? You wouldn't subject a super-light bike
of *any* material to that kind of use. That's not what they're made for, at
least not yet. The market for carbon fiber bikes is very specifically at the
high-performance end of the market, and has yet to invade the utility bike
market. For it to do so, they would, indeed, have to be made quite
differently than they are now. Just as utility bikes of any other material
are made differently from super-light performance-oriented models of the
same material.

HOWEVER---

> The
> times I see lots of carbon bikes are when I get out relatively early
> on weekend mornings and happen to ride on relatively untrafficked
> roads on the perimeter of the city. At those times I see clumps of
> people in stretchy clown suits riding on plastic bikes.

Characterizations of recreational riders, whether they be racers training,
wannabes or weekend warriors, as "people in stretchy clown suits riding on
plastic bikes" has nothing to do with the discussion at hand, and comes
across as belittling, at best. We see a fair amount of that type of abuse
here, and fine, I can take it. But what would happen if people were to make
characterizations of the type of person who buys a cheapie *Mart bike
(always, it seems ridden with flat tires) to get to their job, because they
can't afford a car nor a decent bike... that somehow that group is less
worthy than some category of "real" cyclist (according to whomever's
definition)?

You shouldn't see that here, nor would you. And if someone did, I should
hope that a great many would come to the defense of those who are in such a
position that their only use for a bike is basic transportation, and they
could really care less about the bike's nobility, they'd rather be driving a
car.

The cycling world should be all-encompassing, not exclusionary. In my humble
opinion. And you shouldn't seek to gain favor for an argument by making fun
of any particular user group. Again, in my humble opinion.

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


"Chalo" <[email protected]> wrote in message
news:[email protected]...
> Mike Jacoubowsky wrote:
>>
>> Tim McNamara wrote:
>> >
>> > Unfortunately your carbon frame is not readily inspectable for damage.
>> > I hope that is in in fact undamaged.
>>
>> The impact was in 2000; the frame remains in continuous use since then.
>> The
>> fork was replaced, due to a damaged steer column. It would have been
>> replace
>> anyway, since it would have failed the "common sense" test (being that
>> nothing could have been designed to withstand that sort of impact, and
>> thus
>> it cannot be trusted). The frame might have failed the "common sense"
>> test
>> as well, except that I have yet to see, among the many (and I do mean
>> many)
>> thousands of carbon fiber frames that I have sold, a catastrophic failure
>> that happened after an initial incident, and without warning. Please do
>> not
>> take this to mean a frame is safe after a crash. Rather, for my sample
>> size,
>> I see issues with forks, but not frames (dealing strictly with those that
>> I
>> have sold, which is admittedly a base of only one manufacturer).
>
> In my observation, the group of people who ride CFRP bikes is very
> self-selecting. They are, by and large, folks who:
>
> - weigh close to the population median, or less
>
> - have more money to spend than time to ride
>
> - don't lock their bikes up in public racks
>
> - don't store their bikes inside
>
> - are conscious of their appearance and go to lengths to keep their
> bikes clean and unscratched
>
> - ride on Sunday on roads that don't go anywhere
>
> - etc.
>
> I have spent most of my adult life using my bike as regular
> transportation. I see vanishingly few CFRP bikes in the course of my
> riding around town, though I see lots and lots of other bikes. The
> times I see lots of carbon bikes are when I get out relatively early
> on weekend mornings and happen to ride on relatively untrafficked
> roads on the perimeter of the city. At those times I see clumps of
> people in stretchy clown suits riding on plastic bikes.
>
> At those times, I have never noticed them doing any of the sort of
> things that cause veteran commuter bikes to become dinged up and
> stripped of sections of their decals and paint. I have never seem
> them doing the sorts of things that made my Seattle bike messenger
> friends wrap their bikes' frame tubes with tape and fit them with top
> tube pads. I don't even see them doing the transportational sorts of
> things that they might do in their cars.
>
> I only see these folks doing what I've seen from groups of guys
> driving Morgans or riding Panhead Harleys together-- wandering around
> for the sake of wandering around, and for the purpose of showing off
> their pampered shiny machines to each other and a bunch of other folks
> who don't care. And I can't help but suspect that just like Morgans
> and Panhead Harleys, CFRP bikes would be unreliable at best if used
> regularly for most practical vehicular purposes. I could be wrong,
> but the almost complete absence of CFRP bikes on the mean streets has
> got to demonstrate _something_. I think that part of what it
> demonstrates is a short half-life in the real world.
>
> Chalo
>

 

[jim beam]

Michael Press wrote:
> In article <[email protected]>,
> "Mike Jacoubowsky" <[email protected]> wrote:
>
>> That's the part of this discussion I find so incredible. Catastrophic
>> failure modes have been around for as long as manufacturing. Carbon fiber
>> didn't invent them. Carbon fiber didn't cause them. Flawed designs &
>> manufacturing did. Back in the day, we saw a lot of "catastrophic" failures.
>> People have either forgotten about that, or else, because those failures
>> were on "tried & true" technology, materials that had been around for some
>> time, they were, for some reason, tolerated. Why?
>
> Metals give warning. We can look for and _see_ cracks
> in metal frames. A compromised metal frame rides wonky.

if you're lucky - there's no guarantee this will be the case.


> I have experienced it myself. Looked, and behold! a
> crack in the frame. Catastrophic failure is failure
> that gives no warning. Catastrophic failure is _not_
> failure that gives warning that is then ignored by the
> rider.
>

 

[[email protected]]

On Sep 9, 11:37 pm, "Mike Jacoubowsky" <[email protected]> wrote:
> Chalo wrote:
>
> > The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> Characterizations of recreational riders, whether they be racers training,
> wannabes or weekend warriors, as "people in stretchy clown suits riding on
> plastic bikes" has nothing to do with the discussion at hand, and comes
> across as belittling, at best. We see a fair amount of that type of abuse
> here, and fine, I can take it. But what would happen if people were to make
> characterizations of the type of person who buys a cheapie *Mart bike
> (always, it seems ridden with flat tires) to get to their job, because they
> can't afford a car nor a decent bike... that somehow that group is less
> worthy than some category of "real" cyclist (according to whomever's
> definition)?
>
> You shouldn't see that here, nor would you. And if someone did, I should
> hope that a great many would come to the defense of those who are in such a
> position that their only use for a bike is basic transportation, and they
> could really care less about the bike's nobility, they'd rather be driving a
> car.
>
> The cycling world should be all-encompassing, not exclusionary. In my humble
> opinion. And you shouldn't seek to gain favor for an argument by making fun
> of any particular user group. Again, in my humble opinion.

I agree with Mike's humble opinion.

And I agree, we shouldn't see that sort of snobbery here - the
belittling of utility riders. But let me quote from Buycycling
magazine, October 2007, regarding non-racy bikes and those who use
them for practical purposes: "After they have a few miles under their
wheels some of these utilitarian riders will be hooked and become
cyclists."

Oh? And what are they when they're actually using a bike for
practical transportation? Are they the underclass? Disadvantaged?
Freds? POBs? No, they're cyclists, dammit!

I suppose disparaging either style of cyclist is not a good thing.
But I certainly see a lot less to admire in a person for whom
"cycling" is just spending big bucks on a fragile toy they haul around
on their Escalade's roof rack so they can play racer.

When Buycycling magazine becomes all-encompassing and not
exclusionary, we'll have achieved something. But the magazine, and
it's fans, seem to have a long way to go. In view of that, Chalo's
mild remark seems pretty tame.

But that's just me and my personal taste, I suppose.

- Frank Krygowski

 

[jim beam]

Michael Press wrote:
> In article
> <[email protected]>,
> "Mike Jacoubowsky" <[email protected]> wrote:
>
>>>> Oh, wait, nevermind. It wasn't the material that was the issue, it was
>>>> how
>>>> it was used. Incredibly dangerous failure modes, yet nobody was calling
>>>> for
>>>> manufacturers to stop using aluminum, steel or titanium for bike parts.
>>> Nobody is calling for manufacturers to stop using anything.
>> Perhaps not. Could you sum up what is being suggested? It certainly appears
>> that there are several posters who are saying that carbon fiber is not
>> appropriate for critical (parts that, if they fail, could cause serious
>> injury or death) bicycle parts.
>
> Carbon fiber composite structures are easily damaged
> when struck on the surface. The strike can cause
> delamination and broken fibers.

define "strike" and put numbers to it. without that, you're just
ignoring reality that cfrp bike components are used daily, globally, by
millions of people, and the incidence of failure is below the noise of
other bike system failures.


> The damage can be
> invisible.

just like metal fatigue. only carbon has better fatigue characteristics.


> The compromised structure will deteriorate
> and fail without warning.

now that's a massive exaggeration. the probability of carbon suddenly
shattering like glass, no warning, is slim to zero. typical failure is
that of tearing and progressive fracture, over time, accompanied by much
audible warning.


> Warning is when the structure
> starts to behave differently such as wallowing while
> steering can indicate a compromised head tube joint in
> a metal frame.
>
> Personally, I think manufacturers can eventually figure
> out how to make frames from carbon fiber composite that
> will resist direct strike damage.

really? what numbers should they design to? oh, wait, we haven't
defined "impact" yet.


> Or perhaps they could
> put an indicater layer that would signal a no go
> condition.

they could embed microphones too and they can be monitored by the flight
controller...


> I do not see how they can deal with the
> brittle fracture dynamics of carbon fiber composites.

if you haven't studied the subject, why are you expressing underinformed
worries as fact? metal fatigue is a highly complex subject and full of
anomalies - why are you not even-handedly expressing similar concerns in
that department also?


> I
> think they may know more than they say, but essentially
> cannot say it. I do not think the manufacturers are
> evil.

sure they know more - they know they need to embed microphones for
monitoring by the flight controller!

 

[Mike Jacoubowsky]

>> The cycling world should be all-encompassing, not exclusionary. In my
>> humble
>> opinion. And you shouldn't seek to gain favor for an argument by making
>> fun
>> of any particular user group. Again, in my humble opinion.
>
> I agree with Mike's humble opinion.
>
> And I agree, we shouldn't see that sort of snobbery here - the
> belittling of utility riders. But let me quote from Buycycling
> magazine, October 2007, regarding non-racy bikes and those who use
> them for practical purposes: "After they have a few miles under their
> wheels some of these utilitarian riders will be hooked and become
> cyclists."
>
> Oh? And what are they when they're actually using a bike for
> practical transportation? Are they the underclass? Disadvantaged?
> Freds? POBs? No, they're cyclists, dammit!
>
> I suppose disparaging either style of cyclist is not a good thing.
> But I certainly see a lot less to admire in a person for whom
> "cycling" is just spending big bucks on a fragile toy they haul around
> on their Escalade's roof rack so they can play racer.
>
> When Buycycling magazine becomes all-encompassing and not
> exclusionary, we'll have achieved something. But the magazine, and
> it's fans, seem to have a long way to go. In view of that, Chalo's
> mild remark seems pretty tame.
>
> But that's just me and my personal taste, I suppose.
>
> - Frank Krygowski

I doubt we'll see Bicycling Magazine become that sort of all-encompassing
product, because it wouldn't serve their financial model. They've chosen to
go after a certain type of advertiser, and built a format around that.
Regardless, I sincerely hope that people write letters and send emails to
them because of that remark. It's quite insulting.

Keep in mind that, just a few years ago, I wouldn't have seen it as that big
a thing myself. In my pre-DC Bike Summit days. Plain & simple truth is that
the economic model of my shop depends upon selling bikes that average over
$600. We build all bikes the same way, we service all customers the same
way, and our break-even point on a bike is somewhere around $500. Bikes we
sell for below that we lose money on, when we figure in all the costs
involved (time to build it, 30 day check, time to sell it, cost to floor it,
rent, advertising, all the stuff it costs to run a business). We sold
less-expensive bikes because we didn't want a family to buy their fancier
bikes from us, for example, and have to go someplace else for their kids
bikes. And there was always a sense that it all evened out in the end.

But now I see more to it than that. I have a role to play that goes beyond
just selling & servicing them. I also have an obligation to make sure people
have places to ride them, that they feel safe having their kids ride to
school, that the city doesn't do something stupid that causes grief for
cyclists. I might not be the person selling those bikes, but I benefit down
the road as more people ride, because it increases the overall appeal of
cycling, which means I'll sell more of the product that pays our bills. So
it's not as if it's a selfless desire on my part to make the world a better
place, although I would like to believe I can do something positive,
involving cycling, that can help to achieve that.

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


<[email protected]> wrote in message
news:[email protected]...
> On Sep 9, 11:37 pm, "Mike Jacoubowsky" <[email protected]> wrote:
>> Chalo wrote:
>>
>> > The
>> > times I see lots of carbon bikes are when I get out relatively early
>> > on weekend mornings and happen to ride on relatively untrafficked
>> > roads on the perimeter of the city. At those times I see clumps of
>> > people in stretchy clown suits riding on plastic bikes.
>>
>> Characterizations of recreational riders, whether they be racers
>> training,
>> wannabes or weekend warriors, as "people in stretchy clown suits riding
>> on
>> plastic bikes" has nothing to do with the discussion at hand, and comes
>> across as belittling, at best. We see a fair amount of that type of abuse
>> here, and fine, I can take it. But what would happen if people were to
>> make
>> characterizations of the type of person who buys a cheapie *Mart bike
>> (always, it seems ridden with flat tires) to get to their job, because
>> they
>> can't afford a car nor a decent bike... that somehow that group is less
>> worthy than some category of "real" cyclist (according to whomever's
>> definition)?
>>
>> You shouldn't see that here, nor would you. And if someone did, I should
>> hope that a great many would come to the defense of those who are in such
>> a
>> position that their only use for a bike is basic transportation, and they
>> could really care less about the bike's nobility, they'd rather be
>> driving a
>> car.
>>
>> The cycling world should be all-encompassing, not exclusionary. In my
>> humble
>> opinion. And you shouldn't seek to gain favor for an argument by making
>> fun
>> of any particular user group. Again, in my humble opinion.
>
> I agree with Mike's humble opinion.
>
> And I agree, we shouldn't see that sort of snobbery here - the
> belittling of utility riders. But let me quote from Buycycling
> magazine, October 2007, regarding non-racy bikes and those who use
> them for practical purposes: "After they have a few miles under their
> wheels some of these utilitarian riders will be hooked and become
> cyclists."
>
> Oh? And what are they when they're actually using a bike for
> practical transportation? Are they the underclass? Disadvantaged?
> Freds? POBs? No, they're cyclists, dammit!
>
> I suppose disparaging either style of cyclist is not a good thing.
> But I certainly see a lot less to admire in a person for whom
> "cycling" is just spending big bucks on a fragile toy they haul around
> on their Escalade's roof rack so they can play racer.
>
> When Buycycling magazine becomes all-encompassing and not
> exclusionary, we'll have achieved something. But the magazine, and
> it's fans, seem to have a long way to go. In view of that, Chalo's
> mild remark seems pretty tame.
>
> But that's just me and my personal taste, I suppose.
>
> - Frank Krygowski
>
>

 

[Michael Press]

In article
<[email protected]>,
"Mike Jacoubowsky" <[email protected]> wrote:

> > You did not say that you examined the fracture for corrosion,
> > corrosion that means it had been separating over time.
>
> Obviously, nothing was noticed, prior to the failure. Which, of course, is
> the point. It was entirely unexpected. But to answer the question, no, no
> corrosion, it was a poor forging.
>
> > (Your replies are not prefaced with attribution information.
> > Would you look into that?)
>
> Didn't I include the entire prior post intact at the bottom of my reply? I'm
> not sure what you're saying.

Oh. I see the attribution information in the middle of the
message body, and I expected to see it at the beginning of
the message body. Nevermind.

> "Michael Press" <[email protected]> wrote in message
> news:[email protected]...
> > In article
> > <[email protected]>,
> > "Mike Jacoubowsky" <[email protected]> wrote:
> >
> >> > Let's defined catastrophic failure: the component breaks into two or
> >> > more discrete pieces nearly instantaneously. This is typical of
> >> > brittle
> >> > materials (glass, for example) and not typical of metallic materials
> >> > commonly used in bicycles
> >>
> >> That would have been my Mavic stem (looked to have been made by 3TTT).
> >> Absolutely zero warning. No noise, no looseness. A real-life JRA. Well,
> >> OK,
> >> I was sprinting when it happened. A aluminum, forged quill stem, single
> >> bolt, not hinged. The section of stem that the handlebar-claming bolt
> >> threaded into gave way. No, the threads didn't strip, the entire section
> >> pulled away from the rest of the stem. Quite the rude thing to happen.
> >>
> >> Points to consider- Aluminum. No prior warning. Catastrophic failure.
> >
> > You did not say that you examined the fracture for corrosion,
> > corrosion that means it had been separating over time.
> >
> > (Your replies are not prefaced with attribution information.
> > Would you look into that?)
> >
> > --
> > Michael Press

--
Michael Press

 

[Doug Taylor]

On Mon, 10 Sep 2007 04:31:44 -0000, [email protected] wrote:

>I agree with Mike's humble opinion.
>
>And I agree, we shouldn't see that sort of snobbery here - the
>belittling of utility riders. But let me quote from Buycycling
>magazine, October 2007, regarding non-racy bikes and those who use
>them for practical purposes: "After they have a few miles under their
>wheels some of these utilitarian riders will be hooked and become
>cyclists."
>
>Oh? And what are they when they're actually using a bike for
>practical transportation? Are they the underclass? Disadvantaged?
>Freds? POBs? No, they're cyclists, dammit!
>
>I suppose disparaging either style of cyclist is not a good thing.
>But I certainly see a lot less to admire in a person for whom
>"cycling" is just spending big bucks on a fragile toy they haul around
>on their Escalade's roof rack so they can play racer.
>
>When Buycycling magazine becomes all-encompassing and not
>exclusionary, we'll have achieved something. But the magazine, and
>it's fans, seem to have a long way to go. In view of that, Chalo's
>mild remark seems pretty tame.
>
>But that's just me and my personal taste, I suppose.

This headline showed in our local paper last Friday:
"Bicyclist dies in collision with car."

Witnesses reported a man riding a bicycle down a hill, wearing a
baseball cap (NOT a helmet, note). The cap flew off his head; he
turned around and tried to catch it; he then ran a stop sign and
broadsided the car. Turns out he was - you guessed it - drunk as a
skunk.

Your call: "Bicyclist"? "Cyclist"? Drunk on a bike?

 

[Tim McNamara]

In article <[email protected]>,
"Mike Jacoubowsky" <[email protected]> wrote:

> >> > Nobody is calling for manufacturers to stop using anything.
> >>
> >> Perhaps not. Could you sum up what is being suggested? It
> >> certainly appears that there are several posters who are saying
> >> that carbon fiber is not appropriate for critical (parts that, if
> >> they fail, could cause serious injury or death) bicycle parts.
> >
> > That is exactly what I am saying. I won't presume to speak for
> > anyone else. Could CF be made suitable through the use of
> > different resins? Different layup schedules? More layers? I don't
> > know and will leave that to people who do.
> >
> > As for whether manufacturers should stop using it, that of course
> > is up to them. I will not buy a CF frame, fork, seatpost, stem or
> > handlebar for the reasons I have previously cited which are
> > supported by literature previously referenced. I don't make that
> > decision for anyone else. They may want to buy the things, and
> > given the number of CF bikes I see around here the market seems to
> > be ample. For my uses, CF offers no significant benefits over
> > other materials and poses significant drawbacks.
>
> Tim: Thanks. I thought I was missing the point, going nuts, or a
> combination of the two!

Nope, that's just the usual consequence of long Usenet threads. Things
get blurry after a couple hundred posts and the thread finally dies
because no one is sure what the topic is any more.

> Symptoms for which the obvious cure could only be removal of carbon
> fiber from my diet. :>)

 

[Tim McNamara]

In article <[email protected]>,
Chalo <[email protected]> wrote:

> Sometimes they would bring their underdressed girlfriends along for
> the ride.

You say this like it's a bad thing...

 

[[email protected]]

On Sep 10, 8:57 am, Doug Taylor <[email protected]> wrote:
>
>
> Witnesses reported a man riding a bicycle down a hill, wearing a
> baseball cap (NOT a helmet, note). The cap flew off his head; he
> turned around and tried to catch it; he then ran a stop sign and
> broadsided the car. Turns out he was - you guessed it - drunk as a
> skunk.
>
> Your call: "Bicyclist"? "Cyclist"? Drunk on a bike?

All three, I'd say.

And the last part should be discouraged, since there are indications
drunk cyclists are a very large percentage of the few cycling
fatalities in America. If we could stop those guys from getting
killed, cycling's data would look even better.

It would make a lot more difference than our current focus on hat
styles.

- Frank Krygowski

 

[[email protected]]

On Sep 9, 9:37 pm, "Mike Jacoubowsky" <[email protected]> wrote:
> Chalo: I'm not going to go into everything in your reply point-by-point,
> because, for the most part, I agree!!!
>
> Carbon fiber isn't the ideal material for all kinds of bikes. I never
> suggested it was. Why spend a fortune for a bike that's going to get
> seriously dinged up in normal use? You wouldn't subject a super-light bike
> of *any* material to that kind of use. That's not what they're made for, at
> least not yet. The market for carbon fiber bikes is very specifically at the
> high-performance end of the market, and has yet to invade the utility bike
> market. For it to do so, they would, indeed, have to be made quite
> differently than they are now. Just as utility bikes of any other material
> are made differently from super-light performance-oriented models of the
> same material.
>
> HOWEVER---
>
> > The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> Characterizations of recreational riders, whether they be racers training,
> wannabes or weekend warriors, as "people in stretchy clown suits riding on
> plastic bikes" has nothing to do with the discussion at hand, and comes
> across as belittling, at best. We see a fair amount of that type of abuse
> here, and fine, I can take it. But what would happen if people were to make
> characterizations of the type of person who buys a cheapie *Mart bike
> (always, it seems ridden with flat tires) to get to their job, because they
> can't afford a car nor a decent bike... that somehow that group is less
> worthy than some category of "real" cyclist (according to whomever's
> definition)?
>
> You shouldn't see that here, nor would you. And if someone did, I should
> hope that a great many would come to the defense of those who are in such a
> position that their only use for a bike is basic transportation, and they
> could really care less about the bike's nobility, they'd rather be driving a
> car.
>
> The cycling world should be all-encompassing, not exclusionary. In my humble
> opinion. And you shouldn't seek to gain favor for an argument by making fun
> of any particular user group. Again, in my humble opinion.
>
> --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com
>
> "Chalo" <[email protected]> wrote in message
>
> news:[email protected]...
>
> > Mike Jacoubowsky wrote:
>
> >> Tim McNamara wrote:
>
> >> > Unfortunately your carbon frame is not readily inspectable for damage.
> >> > I hope that is in in fact undamaged.
>
> >> The impact was in 2000; the frame remains in continuous use since then.
> >> The
> >> fork was replaced, due to a damaged steer column. It would have been
> >> replace
> >> anyway, since it would have failed the "common sense" test (being that
> >> nothing could have been designed to withstand that sort of impact, and
> >> thus
> >> it cannot be trusted). The frame might have failed the "common sense"
> >> test
> >> as well, except that I have yet to see, among the many (and I do mean
> >> many)
> >> thousands of carbon fiber frames that I have sold, a catastrophic failure
> >> that happened after an initial incident, and without warning. Please do
> >> not
> >> take this to mean a frame is safe after a crash. Rather, for my sample
> >> size,
> >> I see issues with forks, but not frames (dealing strictly with those that
> >> I
> >> have sold, which is admittedly a base of only one manufacturer).
>
> > In my observation, the group of people who ride CFRP bikes is very
> > self-selecting. They are, by and large, folks who:
>
> > - weigh close to the population median, or less
>
> > - have more money to spend than time to ride
>
> > - don't lock their bikes up in public racks
>
> > - don't store their bikes inside
>
> > - are conscious of their appearance and go to lengths to keep their
> > bikes clean and unscratched
>
> > - ride on Sunday on roads that don't go anywhere
>
> > - etc.
>
> > I have spent most of my adult life using my bike as regular
> > transportation. I see vanishingly few CFRP bikes in the course of my
> > riding around town, though I see lots and lots of other bikes. The
> > times I see lots of carbon bikes are when I get out relatively early
> > on weekend mornings and happen to ride on relatively untrafficked
> > roads on the perimeter of the city. At those times I see clumps of
> > people in stretchy clown suits riding on plastic bikes.
>
> > At those times, I have never noticed them doing any of the sort of
> > things that cause veteran commuter bikes to become dinged up and
> > stripped of sections of their decals and paint. I have never seem
> > them doing the sorts of things that made my Seattle bike messenger
> > friends wrap their bikes' frame tubes with tape and fit them with top
> > tube pads. I don't even see them doing the transportational sorts of
> > things that they might do in their cars.
>
> > I only see these folks doing what I've seen from groups of guys
> > driving Morgans or riding Panhead Harleys together-- wandering around
> > for the sake of wandering around, and for the purpose of showing off
> > their pampered shiny machines to each other and a bunch of other folks
> > who don't care. And I can't help but suspect that just like Morgans
> > and Panhead Harleys, CFRP bikes would be unreliable at best if used
> > regularly for most practical vehicular purposes. I could be wrong,
> > but the almost complete absence of CFRP bikes on the mean streets has
> > got to demonstrate _something_. I think that part of what it
> > demonstrates is a short half-life in the real world.
>
> > Chalo

Chalo is not off in his characterization. We look like a bunch of
clowns. I wear the clown outfit because it happens to be beneficial
for riding, but come-on we look like nerds, period. There are athletes
from two sports that need to stay out of coffee shops: cyclists and
baseball players.

Just like in Chalo's description, I ride my bike on weekends with
groups going nowhere for quite a while looking like a nerd. a lot of
my riding partners have carbon fiber bikes. These are the wealthiest
ones of the bunch. We all carry cells, so if something goes wrong, we
call someone to pick us up. We are middle aged nerds piling miles as a
way to face the insecurity that we are potbellied, grayhaired and
getting older by the second. I'd still rather do this than play golf.

I must say that I don't have a carbon fiber bike and I don't have
boutique wheels. In fact, my front wheel is a 36 spoke mavic ma 40.
someone noticed my wheel and asked me if that was from a cart. They
couldn't believe that it had so many spokes and that the rims where so
low profiled.

Andres

 

[Mike Jacoubowsky]

>> Didn't I include the entire prior post intact at the bottom of my reply?
>> I'm
>> not sure what you're saying.
>
> Oh. I see the attribution information in the middle of the
> message body, and I expected to see it at the beginning of
> the message body. Nevermind.

I realize my "style" is a bit different than most. I have trouble reading
through 200-line postings trying to find what's new & relevant, so when I'm
adding something to a long-ish thread, I'll put the part that's relevant to
what I'm adding at the top (along with my reply) and then include the whole
post below.

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


"Michael Press" <[email protected]> wrote in message
news:[email protected]...
> In article
> <[email protected]>,
> "Mike Jacoubowsky" <[email protected]> wrote:
>
>> > You did not say that you examined the fracture for corrosion,
>> > corrosion that means it had been separating over time.
>>
>> Obviously, nothing was noticed, prior to the failure. Which, of course,
>> is
>> the point. It was entirely unexpected. But to answer the question, no, no
>> corrosion, it was a poor forging.
>>
>> > (Your replies are not prefaced with attribution information.
>> > Would you look into that?)
>>
>> Didn't I include the entire prior post intact at the bottom of my reply?
>> I'm
>> not sure what you're saying.
>
> Oh. I see the attribution information in the middle of the
> message body, and I expected to see it at the beginning of
> the message body. Nevermind.
>
>> "Michael Press" <[email protected]> wrote in message
>> news:[email protected]...
>> > In article
>> > <[email protected]>,
>> > "Mike Jacoubowsky" <[email protected]> wrote:
>> >
>> >> > Let's defined catastrophic failure: the component breaks into two
>> >> > or
>> >> > more discrete pieces nearly instantaneously. This is typical of
>> >> > brittle
>> >> > materials (glass, for example) and not typical of metallic materials
>> >> > commonly used in bicycles
>> >>
>> >> That would have been my Mavic stem (looked to have been made by 3TTT).
>> >> Absolutely zero warning. No noise, no looseness. A real-life JRA.
>> >> Well,
>> >> OK,
>> >> I was sprinting when it happened. A aluminum, forged quill stem,
>> >> single
>> >> bolt, not hinged. The section of stem that the handlebar-claming bolt
>> >> threaded into gave way. No, the threads didn't strip, the entire
>> >> section
>> >> pulled away from the rest of the stem. Quite the rude thing to happen.
>> >>
>> >> Points to consider- Aluminum. No prior warning. Catastrophic failure.
>> >
>> > You did not say that you examined the fracture for corrosion,
>> > corrosion that means it had been separating over time.
>> >
>> > (Your replies are not prefaced with attribution information.
>> > Would you look into that?)
>> >
>> > --
>> > Michael Press
>
> --
> Michael Press

 

[Luke]

In article <[email protected]>,
<[email protected]> wrote:

> > The cycling world should be all-encompassing, not exclusionary. In my humble
> > opinion. And you shouldn't seek to gain favor for an argument by making fun
> > of any particular user group. Again, in my humble opinion.

Noble sentiment that. Let's not restrict it to the velo-world!

 

[Luke]

In article <[email protected]>, A Muzi
<[email protected]> wrote:

> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.

Good point. Vis materials, if there's a r.b.t. consensus I've noticed
it's this: 'stoopid lite' for utility/casual purposes is a mistake, be
it steel, Al, low spoke counts, or CF. But where that threshold falls
is up for further debate!

 

[Michael Press]

In article <[email protected]>,
A Muzi <[email protected]> wrote:

> >> Let's defined catastrophic failure: the component breaks into two or
> >> more discrete pieces nearly instantaneously. This is typical of brittle
> >> materials (glass, for example) and not typical of metallic materials
> >> commonly used in bicycles
>
> Mike Jacoubowsky wrote:
> > That would have been my Mavic stem (looked to have been made by 3TTT).
> > Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> > I was sprinting when it happened. A aluminum, forged quill stem, single
> > bolt, not hinged. The section of stem that the handlebar-claming bolt
> > threaded into gave way. No, the threads didn't strip, the entire section
> > pulled away from the rest of the stem. Quite the rude thing to happen.
> > Points to consider- Aluminum. No prior warning. Catastrophic failure.
>
> I haven't been much involved in this thread for many reasons but if you
> think French stems are scary, what about all the aluminum Pivo bars
> which snapped right next to the stem? After observing many iterations
> of frame and equipment failures, I can match examples - and
> counterexamples- with anyone.
>
> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.

The anecdotes abound; the painstaking forensic
examinations of the aftermath are scarce on the ground.
Show me the pictures of all the broken parts;
macrophotgraphs of the fractures in good light. Tell me
the complete story, the impact history, the
embarrassing details of the incident.

--
Michael Press

 

[Jambo]

"Peter Cole" <[email protected]> wrote in message
news:[email protected]...
>
> You were trying to back up your contention of CF toughness by citing a 30
> year old anecdote (of dubious veracity) about a fiberglass, Nomex
> honeycomb and titanium structure's resistance to bullets. Then you get
> caught. Then you try to weasel out of it. Then you cop an attitude as you
> spew more ****. The "jim beam" tri-fecta.

The anecote's just a made-up story, as proven in my other post.

 

[Jambo]

"Mike Jacoubowsky" <[email protected]> wrote in message
news:[email protected]...
> Chalo: I'm not going to go into everything in your reply point-by-point,
> because, for the most part, I agree!!!
>
> Carbon fiber isn't the ideal material for all kinds of bikes. I never
> suggested it was. Why spend a fortune for a bike that's going to get
> seriously dinged up in normal use? You wouldn't subject a super-light bike
> of *any* material to that kind of use. That's not what they're made for,
> at least not yet. The market for carbon fiber bikes is very specifically
> at the high-performance end of the market, and has yet to invade the
> utility bike market. For it to do so, they would, indeed, have to be made
> quite differently than they are now. Just as utility bikes of any other
> material are made differently from super-light performance-oriented models
> of the same material.

This is in fact the whole issue that's been raised in bike CF components.
If I can succinctly encapsulate, it is the higher risk of non-visible damage
with CF components compared to metal components, the types of damage caused
by handling, and wear and tear.

There is a lot of data supporting this fact in the aircraft industry, why
are you looking at the bike industry differently?

No one's arguing that CF cannot take higher duty loads than metals.

 

[Jambo]

"jim beam" <[email protected]> wrote in message
news:[email protected]...
> Jambo wrote:
>>
>> Great. Again, no one said that every and any crash will result in CF
>> frame failure. Without knowing the forces involved in your crashes, it's
>> only deduction that you did not damage it.
>
> and it's only presumption that you did!

Eh? I deduced his crash cause? You been hitting the sauce again beamboy?

> so, to recap, carbon is good, except for when it's not. brilliant.

HAHAHAHAHA! Excellent example of beamboy's height of intellectual capacity
to understand!

Do you understand anisotropy? Look it up, then look up CFC anisotropy, then
look up surface damage, then... oh sheeit, just get a new brain, beamboy!

Thanks beamboy, you sure crack me up (like a CF handlebar!)

 

[Jay Beattie]

On Sep 9, 8:11 pm, A Muzi <[email protected]> wrote:
> >> Let's defined catastrophic failure: the component breaks into two or
> >> more discrete pieces nearly instantaneously. This is typical of brittle
> >> materials (glass, for example) and not typical of metallic materials
> >> commonly used in bicycles
> Mike Jacoubowsky wrote:
> > That would have been my Mavic stem (looked to have been made by 3TTT).
> > Absolutely zero warning. No noise, no looseness. A real-life JRA. Well, OK,
> > I was sprinting when it happened. A aluminum, forged quill stem, single
> > bolt, not hinged. The section of stem that the handlebar-claming bolt
> > threaded into gave way. No, the threads didn't strip, the entire section
> > pulled away from the rest of the stem. Quite the rude thing to happen.
> > Points to consider- Aluminum. No prior warning. Catastrophic failure.
>
> I haven't been much involved in this thread for many reasons but if you
> think French stems are scary, what about all the aluminum Pivo bars
> which snapped right next to the stem? After observing many iterations
> of frame and equipment failures, I can match examples - and
> counterexamples- with anyone.
>
> Mike has a good point - "sudden catastrophic failure" anecdotes abound
> in all materials. Here on r.b.t., though, we haven't made the leap from
> anecdote to data or a unified theory yet. Neither 'carbon good' nor
> 'carbon bad' have convinced me.

Frankly, I'm totally confused about this. Most of my serious riding is
done with an engineer friend who works in the industry (but not with
CF -- except that he gets pro-deals on everything and can afford a
mega-$ CF frame). I bring him up to speed on the latest RBT
CFcontroversy, and his comment is "do you see this stuff breaking all
over the place?" He backs off and echos the concern about using CF
where it can get mechanically damaged, but otherwise he thinks it is
proven in well made bike frames.

 

[John Dacey]

On Mon, 10 Sep 2007 15:37:17 -0600, [email protected] wrote:

>Personally, I'm not sure that you guys without skidplates are really
>motorcyclists, but I can't say that you irritate me with your road
>toys.

Of course, it's also a mystery to many folks why trials riders choose
to clambor across rocks on a motorcycle that wouldn't outpace a
glacier with the same agenda.

*********************************************

The Style Police: Men of Steel

Were I a lesser man, you might think me sanctimonious.
My modesty’s so false, it’s practic’ly felonious.
Others, you’ll discover, are a trifle acrimonious
When I dispense advice (I’m a cycling Polonius).

You’re bike’s completely wrong for you -- it’s really quite pathetic;
Offensive in each ev’ry way: material, cosmetic.
To fix the failures I’ve foretold (I’m also quite prophetic),
I’ll be your guide along the righteous path of the Ascetic.

Your frameset should be made of steel and fully lugged is the ideal.
Paint it in a boring color, something quite funereal.
The gravitas imbued in me from only using iron
Makes it the stuff of bicycles for which always I yearn.

I’ve castigated schoolgirls here with nary an apology
For questioning my treatises on wheel-spoke thanatology.
I’ll do the same for you, should you show the temerity
To challenge my encyclicals on bearing-ball asperity.

Avoid new-fangled fabrics with an effort most concerted.
Lycra, Cool-Max, Spandex are the cloths of the perverted --
About your every secret, your friends will be alerted.
So neophobes like me are most at home when we’re hairshirted.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
Phone: 305-273-4440
http://www.businesscycles.com
-------------------------------