Training or Plain Riding?

On Dec 10, 5:13*pm, John Forrest Tomlinson
wrote:
On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C

wrote:
Yeah JT I am, and you know the person well since they are NECSA, and
Nebra.
Their experience is that steel and aluminium give warning. or crack
before snapping catastrophically. I haven't studied it, they have.

You're saying something slightly different now - that it's about
warning before catosthropic failure.

But back to the original statement -- the idea that carbon forks have
any extra tendency to fail more often than steel or aluminum is just
baloney, despte whatever studies this person has claimed to have done.

I don't get that. If a study is valid it should be taken seriously. I
just don't know of any such study.

I agree with you that carbon is a safe material if well constructed.
Once after cutting a carbon steer tube I spent some time playing with
the scrap piece and came away impressed with its strength. I've used a
lot of carbon and never had a failure.

Bret

On Dec 10, 7:26*pm, Bret wrote:
On Dec 10, 5:13*pm, John Forrest Tomlinson
wrote:

On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C

wrote:
Yeah JT I am, and you know the person well since they are NECSA, and
Nebra.
Their experience is that steel and aluminium give warning. or crack
before snapping catastrophically. I haven't studied it, they have.

You're saying something slightly different now - that it's about
warning before catosthropic failure.

But back to the original statement -- the idea that carbon forks have
any extra tendency to fail more often than steel or aluminum is just
baloney, despte whatever studies this person has claimed to have done.

I don't get that. If a study is valid it should be taken seriously. I
just don't know of any such study.

I agree with you that carbon is a safe material if well constructed.
Once after cutting a carbon steer tube I spent some time playing with
the scrap piece and came away impressed with its strength. I've used a
lot of carbon and never had a failure.

Bret

Bret look at the problems/recalls with the early Look forks,
etc...This falls in line with the make sure it's good before using it
argument. No question carbon done right is a solid material, but how
many errors happened to get to today's reliabilty?
I could point out that blacktop is black and JT would call me an
idiot and mock me, or antything I cite.
Bill C

On Wed, 10 Dec 2008 16:25:56 -0800 (PST), Bill C
wrote:

On Dec 10, 7:13=A0pm, John Forrest Tomlinson
wrote:
On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C

wrote:
Yeah JT I am, and you know the person well since they are NECSA, and
Nebra.
Their experience is that steel and aluminium give warning. or crack
before snapping catastrophically. I haven't studied it, they have.

You're saying something slightly different now - that it's about
warning before catosthropic failure.

But back to the original statement -- the idea that carbon forks have
any extra tendency to fail more often than steel or aluminum is just
baloney, despte whatever studies this person has claimed to have done.

Hey since I haven't researched it your opinion is as good as theirs,
except anecdotally they claim to have picked more kids up off the
pavement with carbon forks than others.

If you've been around racing or cyclilng, it's pretty obvious who is
right on this one.

But hey, if you want to relay nonsense and then sorta disavow it, go
ahead.

Just mock them and move on.

"Bill C" wrote in message
...

look at the problems/recalls with the early Look forks,
etc...This falls in line with the make sure it's good before using it
argument.

The real problem is that it is fairly easy to get errors in the layup and
when you make progressively lighter and lighter frames and forks, errors
become a great deal more dangerous.

No question carbon done right is a solid material, but how
many errors happened to get to today's reliabilty?

And THAT'S the point. A bubble in the steel tube can cause a crack. Since
there is so much extra strength in a steel tube it usually can fail to the
point where you discover the failure without catastrophic failures.

I could point out that blacktop is black and JT would call me an
idiot and mock me, or antything I cite.

I can't understand what happened to that guy who used to have all the really
intelligent questions and/or answers.

On Wed, 10 Dec 2008 16:26:36 -0800 (PST), Bret
wrote:

On Dec 10, 5:13*pm, John Forrest Tomlinson
wrote:
On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C

wrote:
Yeah JT I am, and you know the person well since they are NECSA, and
Nebra.
Their experience is that steel and aluminium give warning. or crack
before snapping catastrophically. I haven't studied it, they have.

You're saying something slightly different now - that it's about
warning before catosthropic failure.

But back to the original statement -- the idea that carbon forks have
any extra tendency to fail more often than steel or aluminum is just
baloney, despte whatever studies this person has claimed to have done.

I don't get that. If a study is valid it should be taken seriously. I
just don't know of any such study.

It's because I know about this person and a "study" be this person is
probably an experience one anecdote second hand and two personal
experience with other factors involved. Plus influence from a great
guy who builds nice bikes with steel forks.

Not the tight personal observation I'm bringing to it (and you bring
below) let alone a real study.

I agree with you that carbon is a safe material if well constructed.
Once after cutting a carbon steer tube I spent some time playing with
the scrap piece and came away impressed with its strength. I've used a
lot of carbon and never had a failure.

On Wed, 10 Dec 2008 16:33:06 -0800 (PST), Bill C
wrote:


Bret look at the problems/recalls with the early Look forks,
etc...This falls in line with the make sure it's good before using it
argument. No question carbon done right is a solid material, but how
many errors happened to get to today's reliabilty?

So this person you're talking about is going to use the far past to
justify equipment decisions forever? And considering how many cheap
bikes come with carbon forks nowaday, limit the riders choices?

Great.

I know this person is old, but I guess she wasn't around back in the
day when steel forks broke a lot, otherwise this person wouldn't be
letting kids ride anything.

I'm not dissing this person in general, but this decision is dopey.
If this person wants to push the kids to not think about bikes too
much, and is getting bikes with good steel forks, great. But wong
info has to be called wrong info, not backed perpetuated.

I could point out that blacktop is black and JT would call me an
idiot and mock me, or antything I cite.

No, I don't stalk you except about your poltiical nonsense. And in
this case, a tech myth. But if you want to take it personal, go
ahead.

"Bret" wrote in message
...
On Dec 10, 4:01 pm, "Tom Kunich" cyclintom@yahoo. com wrote:

By the way Bret, I haven't noticed that anyone has been talking about
broken
forks and frames either but according to several shops in my area there
are
a great deal more such failures than before.

I don't doubt that carbon fails at a higher rate when crashed hard.

There are two important failure points - yield strength and ultimate
strength. In steel these points are pretty far from each other so you get
BENDING before you get total collapse. You feel or otherwise notice this
sort of failure and take actions before the failures are serious.

In top of the line aluminum frames these points are much nearer one another
and until recently what manufacturers of aluminum frames did was to
significantly overbuild their frames so that it took a lot to reach the
yield point. Lately they've been building much lighter aluminum frames are
they're becoming dangerous since they can fail suddenly and completely.

Carbon fiber in the sort of layups they use for extremely light frames and
forks have very little difference between the yield strength and the
ultimate strength and essentially what happens is that it fails suddenly and
completely.

Early Look frames and those from conservative manufacturers are
significantly overbuilt to achieve reliability. But the racing frames that
are super light are becoming more and more common among street racers and
these bikes are dangerous. A weight difference of just 1/2 lb could mean the
difference between sudden failure and long term reliability.

On Dec 10, 6:07*pm, "Tom Kunich" cyclintom@yahoo. com wrote:
"Bret" wrote in message

I don't doubt that carbon fails at a higher rate when crashed hard.

There are two important failure points - yield strength and ultimate
strength. In steel these points are pretty far from each other so you get
BENDING before you get total collapse. You feel or otherwise notice this
sort of failure and take actions before the failures are serious.

In top of the line aluminum frames these points are much nearer one another
and until recently what manufacturers of aluminum frames did was to
significantly overbuild their frames so that it took a lot to reach the
yield point. Lately they've been building much lighter aluminum frames are
they're becoming dangerous since they can fail suddenly and completely.

Carbon fiber in the sort of layups they use for extremely light frames and
forks have very little difference between the yield strength and the
ultimate strength and essentially what happens is that it fails suddenly and
completely.


Engineer Man,

This is a misunderstanding of the difference between
yield failures and fatigue failures, and the relative
danger of each in bicycle applications.

You get bending without breaking in steel from a single
high force incident, like a crash. You crash, you pick the
bike up (or someone else does if you're not in one piece)
and it's bent if it's steel, broke if it's aluminum.
Who cares? You're still on the ground.

Fatigue failures without high forces are where the danger
is in bicycles. You don't notice that a part is cracked
halfway through until it cracks the rest of the way and
you fall down. It is true that many steel alloys have a
fatigue limit and aluminum doesn't, but this is somewhat
academic since steel parts that are not overbuilt can
still fatigue and fail.

Ultralight stuff will have a tendency to fatigue and fail
whether it is steel, aluminum, titanium, carbon, or overly thin
Spandex shorts material. There are some places
where steel is desirable due to dimensional limitations
(pedal and traditional BB spindles) but not because it's
magically immune to failure.

Back in the day, you could have bought a steel frame
made out of superlight tubing (KL, Foco?) and it would
be light, but it would eventually break under normal use.
Most people wouldn't sell or buy such a frame then.

If anything, aluminum and carbon allow the manufacturers
to make superlight frames with a lower failure rate. But
there is still a failure rate, because of Fatties like Justin
the Bianchi man and your good self, buying 2.5 lb frames
and expecting them to last as long as 4 lb frames.
You can't buy speed. At least, you can't buy more than
a little speed, and what you can buy is in aero wheels
more than lightweight crap.

So if you aren't willing to invest time and money in inspecting
and replacing ultralight stuff, don't buy ultralight stuff.

Ben
RBR Personal Shopper

" wrote in message
...

This is a misunderstanding of the difference between
yield failures and fatigue failures, and the relative
danger of each in bicycle applications.

Maybe you could point out where I mentioned fatigue failures?

You get bending without breaking in steel from a single
high force incident, like a crash. You crash, you pick the
bike up (or someone else does if you're not in one piece)
and it's bent if it's steel, broke if it's aluminum.
Who cares? You're still on the ground.

Perhaps you ought to actually pay attention to what I was saying instead of
what you wish I had said that you could criticize?

Fatigue failures without high forces are where the danger
is in bicycles.

Perhaps you didn't follow the idea of construction errors?

You don't notice that a part is cracked
halfway through until it cracks the rest of the way and
you fall down.

Most steel frame failures of that sort leaves the bike able to be ridden
home.

Ultralight stuff will have a tendency to fatigue and fail
whether it is steel, aluminum, titanium, carbon, or overly thin
Spandex shorts material. There are some places
where steel is desirable due to dimensional limitations
(pedal and traditional BB spindles) but not because it's
magically immune to failure.

Now where did I say that steel didn't fail?

Perhaps you ought to actually add to a conversation instead of trying to
shoot someone down to such an extend that you will purposely change the
meaning of the discussion?

In article
,
Amit Ghosh wrote:

On Dec 10, 6:16*am, John Forrest Tomlinson

Yeah. One easy way for bike racing to stay more reasonable in pricing
would be to require rims be made of metal and not more than 2cm deep
or something.

dumbasses howard and JT ,

i think the rules make it so that the sport is fair already.

there's nothing wrong with people that want to spend $10,000 on a bike
or discuss the merits of different spoke counts all day, but it's a
hobby which has nothing to do with bike racing.

it's just a distraction, but most racers don't realize until they've
been racing for 5 yrs or so.

The fastest new-to-the-sport rider I ever saw made his introductions by
riding away from a Cat 4/5 field on one of the hilliest road circuits we
do locally (Tom Furst, Westside Classic).

He did this 3 or 4 years ago, on a steel six-speed Pinarello.

He went on to other non-racing hobbies, but I didn't get an impression
the bike was a major impediment.

I'd go so far as to guess (bet?) that any rider good enough to turn pro
would be able to make it to Cat 2 with relative ease on a bike no better
than that one. If you want an off-the-rack example, I'd say that a
Pro-potential rider could upgrade from Cat 5 to Cat 2 (at least in our
local series) in one season, using an off-the-rack Sora-equipped bike.
That is a bike that costs about $600-700 at full MSRP.

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