Grant Petersen / Rivendell on carbon forks

On 20 June, 10:49, m-gineering wrote:
Tim McNamara wrote:
*CFR water bottle cages-
I'd be willing to use those.

Bloody things, many are so thin/sharp you can easily cut your hands when
washing a bike

Get a black polythene cage and pencil some lines on it for a similar
effect.

Op 20-6-2010 11:49, m-gineering schreef:
Tim McNamara wrote:
CFR water bottle cages- I'd be willing to use those.

Bloody things, many are so thin/sharp you can easily cut your hands when
washing a bike




Agreed. I spend 1 hour deburring mine. Never buy them again. Only King
cages for me.

Lou

On Jun 20, 7:27*am, thirty-six wrote:
On 20 June, 10:49, m-gineering wrote:

Tim McNamara wrote:
*CFR water bottle cages-
I'd be willing to use those.

Bloody things, many are so thin/sharp you can easily cut your hands when
washing a bike

Get a black polythene cage and pencil some lines on it for a similar
effect.

Riding through central Kansas in mid-summer I learnt
about full bottles and plastic bottle cages. On the
other hand, they are quite lightweight. On the gripping
hand, they prevent theft by making any bicycle look
like a department-store jalopy.

On Jun 19, 8:40*pm, Jay Beattie wrote:
On Jun 19, 3:38*am, SMS wrote:

incredulous wrote:
Any comment here on this strong anti-carbon position? He's making up
steel forks, not expecting to sell many, and even buying back your old
carbon fork, such great risk does he think the carbon fork poses to
your health.

Consider a carbon fork a wear item and replace it periodically, every
few thousand miles.

His statement "Maybe it was a manufacturing flaw that went undetected,
or a weakness that developed through use" is true, but the latter is
much more likely than the former, and the former can occur no matter
what the material (though it's less likely with steel or aluminum than
with CF).

I would have to do a lot of research to convince myself that carbon
steerers are safe and durable. I have gotten good service out of my CF
forks with aluminum and steel steerers. In any event, someone should
do a real survey to find out what percentage of CF forks are failing
and by what mode. There are so many on the market now that if there
were a serious problem, I would expect to see an epidemic of failures.
-- Jay Beattie.

You mean you seek to form an evidence based opinion instead of
divining wisdom from fresh goat viscera??

On Jun 20, 10:49*am, m-gineering wrote:
Tim McNamara wrote:
*CFR water bottle cages-
I'd be willing to use those.

Bloody things, many are so thin/sharp you can easily cut your hands when
washing a bike

What you get for washing your bike instead of riding it...

--
/Marten

info(apestaartje)m-gineering(punt)nl

Just to prove my street cred, at the best of times an ironic
statement, I have a piece of carbon fibre on my bike:
http://www.chainreactioncycles.com/M...?ModelID=14708
It works well without cutting up my hands or knees but I doubt it is
the lightest bottle cage on the market. Has lasted about six or seven
years now, which isn't bad for carbon fibre.

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

On Jun 20, 8:10*am, Lou Holtman wrote:
Op 20-6-2010 5:56, Mike Jacoubowsky schreef:

I set up my bike without using a torque wrench a while back (built it at
home, not at the shop, and didn't have a torque wrench available). So I
checked it a few months later (my goodness, I didn't crash& *die in the
meantime???) and found that all six bolts on my stem (the two that clamp
the steer tube, and the four clamping the bars) were under-spec for
torque, as much as 20%. But never any slippage, and they felt pretty
tight. I think you'd need to be pretty ham-fisted to exceed the max
torque spec, and taking it to 10nm (double) would be darn near
impossible.

Exactly. Gorilla's will break everything.

Lou

You and Mike are talking about bike shop guys and very experienced
owners, Lou. I'm not so sure that the casual cyclist/mechanic today
can get away without a torque wrench, even if he isn't into carbon
fibre bikes. For instance, the tightening torque of a Rohloff QR is
given as as from 3Nm and it is easy enough to exceed the 7Nm max
simply by not paying attention.

I no longer let the local bike shop operators, relicts of the
blacksmith age, tighten any bolts whatsoever on my bike, after I saw a
guy crack a seatpost collar while saying to me as he refused the
torque wrench I had brought and was offering him, "I know what I'm
doing." I do it myself, with a torque wrench.

Andre Jute
Relentless rigour -- Gaius Germanicus Caesar

On Jun 19, 7:10*pm, "Mike Jacoubowsky"
wrote:
"David Scheidt" wrote in message

...





landotter wrote:
:On Jun 19, 10:41 am, Tim McNamara wrote:
: In article
: ,
:
:
:
:
:
: landotter wrote:
: On Jun 18, 5:13 pm, Jay Beattie wrote:
: On Jun 18, 1:38 pm, incredulous wrote:
:
: Any comment here on this strong anti-carbon position? He's
making
: up steel forks, not expecting to sell many, and even buying
back
: your old carbon fork, such great risk does he think the
carbon
: fork poses to your health.
:
: http://www.rivbike.com/products/show...ms-fork/50-718
:
: Not a troll's question. I ride a glued aluminum fork, myself.
I
: do wonder how much fragility can be built into carbon forks
while
: paring more and more weight off of them, and at what place
: riders, even pros, say, "No, that's just too risky."
:
: Carbon forks rarely fall apart, and when they do, it is because
of
: inadequate bonding, e.g., someone forgot to glue a leg to a
crown.
: That has been my experience. I have seen steel forks break for
the
: same reason -- someone tack brazed the leg to the crown but did
not
: finish off the fork.
:
: Aluminum forks can fall apart for the same reasons, and
: historically, some were dangerous due to the joining of
dissimilar
: materials (Viscount/Lambert). Modern bonded aluminum forks are
: everywhere and seem to have a good service record.
:
: The deal is that with CF, it can be damaged in a way that does
not
: show and then can fail later. I ride CF forks and have since
they
: hit the market (starting with first generation Kestrel forks)
and
: have never had a set fail. But then again, the one time I had a
: bad frontal crash while riding a CF fork, I replaced the fork
just
: to be safe (it was a cheapie fork). Absent damage, though, they
: aren't just falling apart.
:
: Grant is right that CF is not as safe as steel under some
: circumstances (where there is latent damage). His forks look
like
: a nice product at a not too outrageous price. I like that crown
: (with no internal plug stress risers) and the drop outs, too.
If I
: had a steel bike that needed a fork, I'd consider that one. -- *
Jay
: Beattie.
:
: Every con-man's story needs a grain of truth. But if crabon forks
: were raging liabilities--they would get banned like Jarts were.
:
: Peterson's replacement forks are handsome and well priced--his
: tactics of marketing through FUD are loathsome.
:
: Loathsome also is your tarring of Petersen- who has been known as
one of
: the bike industry's stand-up guys throughout his career and whose
: company does a lot of philanthropy- as a "con man."

:I called his FUD loathsome. The guy is a character, mostly
admirable--
:but I won't stand for more unnecessary fear injected into cycling
:dialog.

Have you paid attention to the problem trek is having with their
carbon forks? *If you torque the stem bolts to enough preload that
they don't fall out (and cause your bars to fall off), they break.
Trek is specifically instructing people to install their stems so that
the bolts fall out. *Now that's a safe product!

--
sig 89

4mm Bolts do not fall out, nor do they loosen, at 5nm of torque. Nor can
you twist the stem on the fork at the recommended torque.
Improperly-designed stems that point-load a carbon steer tube are an
issue, as is installing a stem without using a 5mm spacer on top of it
(to prevent compression and cracking of the steer tube when the top cap
is tightened down). There is an issue that the industry has no testing
standards for steer tube/stem interfaces on advanced materials, and in
the absence of that, it is wise to stick only to what the manufacturer
recommends, because that combination *has* been tested.

Carbon fiber is not an adjective. It's a material, which can be used to
make ultra-light equipment that needs more care & attention than
something built using more of it. I have owned four carbon bikes since
1992, and have ridden, and will continue to ride, without fear that
they're about to fall apart underneath me. On the other hand, I have had
three stem failures (two quill one threadless).

Mike, I think you and your shop are subject to significant liability
unless you thoroughly test each and every one of your products. To
that end, you should send me a Madone 6.9 (62cm) for 3-5 years of
rigorous test riding.

I have defended one broken CF fork case that involved a manufacturing
error (inadequate bond between fork and crown). I have had a half-
dozen aluminum shock fork cases, mostly involving a fork that was
recalled back in the early-mid 90s. One shock fork case where the
owner monkeyed with it and it broke (that went to trial -- I won). I
have one current case involving a broken aluminum fork -- both legs
snapped JRA (not). The front rim was miraculously bent, and the
metallurgist said it was an over-load failure. Even before I got an
expert, I took one look at the pictures and said "the dude hit
something."

There is a local case against Wound-Up that I didn't get involving a
broken CF seat post that is being plaintiffed by a friend of mine.
Clamp broke, and the rider was impaled in the perineum -- which I find
really hard to picture. I have broken clamp bolts, and you either
slide forward or backward. How a guy would impale himself is beyond
me. I have a couple CF posts and simply do not like one-bolt posts
because they are hard to adjust. -- Jay Beattie.

Op 20-6-2010 18:15, Andre Jute schreef:
On Jun 20, 8:10 am, Lou wrote:
Op 20-6-2010 5:56, Mike Jacoubowsky schreef:

I set up my bike without using a torque wrench a while back (built it at
home, not at the shop, and didn't have a torque wrench available). So I
checked it a few months later (my goodness, I didn't crash& die in the
meantime???) and found that all six bolts on my stem (the two that clamp
the steer tube, and the four clamping the bars) were under-spec for
torque, as much as 20%. But never any slippage, and they felt pretty
tight. I think you'd need to be pretty ham-fisted to exceed the max
torque spec, and taking it to 10nm (double) would be darn near
impossible.

Exactly. Gorilla's will break everything.

Lou

You and Mike are talking about bike shop guys and very experienced
owners, Lou. I'm not so sure that the casual cyclist/mechanic today
can get away without a torque wrench, even if he isn't into carbon
fibre bikes. For instance, the tightening torque of a Rohloff QR is
given as as from 3Nm and it is easy enough to exceed the 7Nm max
simply by not paying attention.

I no longer let the local bike shop operators, relicts of the
blacksmith age, tighten any bolts whatsoever on my bike, after I saw a
guy crack a seatpost collar while saying to me as he refused the
torque wrench I had brought and was offering him, "I know what I'm
doing." I do it myself, with a torque wrench.

Andre Jute
Relentless rigour -- Gaius Germanicus Caesar


CF comes with some simple rules. Using a torque wrench is one of them.
People who are not willing to use one should stay away from CF and any
lightweigt stuff instead of getting CF phobic.


Lou

On 20 June, 18:28, Lou Holtman wrote:
Op 20-6-2010 18:15, Andre Jute schreef:



On Jun 20, 8:10 am, Lou *wrote:
Op 20-6-2010 5:56, Mike Jacoubowsky schreef:

I set up my bike without using a torque wrench a while back (built it at
home, not at the shop, and didn't have a torque wrench available). So I
checked it a few months later (my goodness, I didn't crash& * *die in the
meantime???) and found that all six bolts on my stem (the two that clamp
the steer tube, and the four clamping the bars) were under-spec for
torque, as much as 20%. But never any slippage, and they felt pretty
tight. I think you'd need to be pretty ham-fisted to exceed the max
torque spec, and taking it to 10nm (double) would be darn near
impossible.

Exactly. Gorilla's will break everything.

Lou

You and Mike are talking about bike shop guys and very experienced
owners, Lou. I'm not so sure that the casual cyclist/mechanic today
can get away without a torque wrench, even if he isn't into carbon
fibre bikes. For instance, the tightening torque of a Rohloff QR is
given as as from 3Nm and it is easy enough to exceed the 7Nm max
simply by not paying attention.

I no longer let the local bike shop operators, relicts of the
blacksmith age, tighten any bolts whatsoever on my bike, after I saw a
guy crack a seatpost collar while saying to me as he refused the
torque wrench I had brought and was offering him, "I know what I'm
doing." I do it myself, with a torque wrench.

Andre Jute
* Relentless rigour -- Gaius Germanicus Caesar

CF comes with some simple rules. Using a torque wrench is one of them.
People who are not willing to use one should stay away from CF and any
lightweigt stuff instead of getting CF phobic.

Lou

Then there is the question of what to oil the threads with, because if
it contacts the resin, there is the worry of deterioration?

Op 20-6-2010 19:50, thirty-six schreef:
On 20 June, 18:28, Lou wrote:
Op 20-6-2010 18:15, Andre Jute schreef:



On Jun 20, 8:10 am, Lou wrote:
Op 20-6-2010 5:56, Mike Jacoubowsky schreef:

I set up my bike without using a torque wrench a while back (built it at
home, not at the shop, and didn't have a torque wrench available). So I
checked it a few months later (my goodness, I didn't crash& die in the
meantime???) and found that all six bolts on my stem (the two that clamp
the steer tube, and the four clamping the bars) were under-spec for
torque, as much as 20%. But never any slippage, and they felt pretty
tight. I think you'd need to be pretty ham-fisted to exceed the max
torque spec, and taking it to 10nm (double) would be darn near
impossible.

Exactly. Gorilla's will break everything.

Lou

You and Mike are talking about bike shop guys and very experienced
owners, Lou. I'm not so sure that the casual cyclist/mechanic today
can get away without a torque wrench, even if he isn't into carbon
fibre bikes. For instance, the tightening torque of a Rohloff QR is
given as as from 3Nm and it is easy enough to exceed the 7Nm max
simply by not paying attention.

I no longer let the local bike shop operators, relicts of the
blacksmith age, tighten any bolts whatsoever on my bike, after I saw a
guy crack a seatpost collar while saying to me as he refused the
torque wrench I had brought and was offering him, "I know what I'm
doing." I do it myself, with a torque wrench.

Andre Jute
Relentless rigour -- Gaius Germanicus Caesar

CF comes with some simple rules. Using a torque wrench is one of them.
People who are not willing to use one should stay away from CF and any
lightweigt stuff instead of getting CF phobic.

Lou

Then there is the question of what to oil the threads with, because if
it contacts the resin, there is the worry of deterioration?


http://www.bike-components.de/products/info/p12414_Montagepaste-mit-Micropearls.html

Using it for years now.