Cinelli fully-sloping crowns- Mr. Brandt?



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T

Thomas Hood

Guest
Just curiousity but could you explain what you mean by "abrupt transition" and "feathered"?

"Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
internal lug of the crown that cannot be feathered to a gradual transition as an external lug can."

By abrupt transition I assume you meant that internal lug looked like the LCO4 shown here:
http://www.ceeway.com/Fork-Crowns-2.htm
I.e. the end of the lug is perpendicular to the blades and straight.

However it would appear the Cinelli crown's end is not like this:
http://www.ceeway.com/Fork-Crowns.htm The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX all seem
to share this. Do these not have 'internally feathered' ends or have I misunderstood you?

The reason I ask is that I have just aquired an almost new Mercian fillet-brazed reynolds 653 frame
with said crown. Stunning craftmanship; the guy I bought it off had too much money to spend and had
just 'upgraded' to a giant carbon fibre compact!?! I'm not complaining he sold it to me for £75
including a record f/mech and titanium seatpost. However after reading your 'colostomy' incident
story I'm a bit wary of that bit....

TIA,

Thomas Hood
 
A

A Muzi

Guest
"Thomas Hood" <[email protected]> wrote in message
news:[email protected]...
> Just curiousity but could you explain what you mean by "abrupt transition" and "feathered"?
>
> "Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
> internal lug of the crown that cannot be feathered to a gradual transition as an external
> lug can."
>
> By abrupt transition I assume you meant that internal lug looked like the LCO4 shown here:
> http://www.ceeway.com/Fork-Crowns-2.htm
> I.e. the end of the lug is perpendicular to the blades and straight.
>
> However it would appear the Cinelli crown's end is not like this:
> http://www.ceeway.com/Fork-Crowns.htm The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX all
> seem to share this. Do these not have 'internally feathered' ends or have I
misunderstood
> you?
>
> The reason I ask is that I have just aquired an almost new Mercian fillet-brazed reynolds 653
> frame with said crown. Stunning craftmanship;
the
> guy I bought it off had too much money to spend and had just 'upgraded' to
a
> giant carbon fibre compact!?! I'm not complaining he sold it to me for £75 including a record
> f/mech and titanium seatpost. However after reading
your
> 'colostomy' incident story I'm a bit wary of that bit....

Most Mercians I've seen, as most British bikes with that style crown, used a Canetti rather than the
Cinelli crown. ( You may know them best from Raleigh Professionals, Raleigh Competitions and
Holdsworth Pros) Canetti crowns are thinner across the top between the blade and column. Cinellis
are more arched viewed from the front. Cinellis are "waisted" when viewed from above, Canettis are
not, there being a flat face across the front and back. Canettis end more abruptly inside than the
later Cinelli which is shaped such that there is more penetration in front and back than in the
center of the blade.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
 
J

Jobst Brandt

Guest
Thomas Hood writes:

> Just curiousity but could you explain what you mean by "abrupt transition" and "feathered"?

The fork crown that Cinelli among others made popular due to its aesthetic shape, is solid steel
(not hollow) as most fork crowns previously were. Typically the steer tube and fork blades
overlapped and had a band-like structure that enveloped all three tubes as we see on a Masi for
instance. The detail of that crown had features that even without feathering the crown to a smooth
transition, made it in effect the same, similar to the filigree on Singer lugs. These in effect make
a soft transition.

The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end abruptly
(because no one can see this) and out of sight out of mind. However, fork blades fail in fatigue at
this transition, breaking off after an insignificant life duration. As I said, I had tow of these
failures and insisted on an external crown that was filed to have a zero thickness transition. This
has worked for many more miles than any of my Cinelli forks survived.

> "Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
> internal lug of the crown that cannot be feathered to a gradual transition as an external
> lug can."

> By abrupt transition I assume you meant that internal lug looked like the LCO4 shown here:

> http://www.ceeway.com/Fork-Crowns-2.htm

> I.e. the end of the lug is perpendicular to the blades and straight.

Only LC19 has a reasonable shape, and crowns of this design were made for road bicycles. Fork blades
are thinner and lighter than any of these other designs that shorten the fork blade and reach down
to *** with a heavy steel crown. It's all fashion BS.

> However it would appear the Cinelli crown's end is not like this:

http://www.ceeway.com/Fork-Crowns.htm

> The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX all seem to share this. Do these not have
> 'internally feathered' ends or have I misunderstood you?

Not at all. The SCA stops abruptly and that is where fork blades fail.

> The reason I ask is that I have just acquired an almost new Mercian fillet-brazed Reynolds 653
> frame with said crown. Stunning craftsmanship; the guy I bought it off had too much money to spend
> and had just 'upgraded' to a giant carbon fibre compact!?! I'm not complaining he sold it to me
> for £75 including a record f/mech and titanium seatpost. However after reading your 'colostomy'
> incident story I'm a bit wary of that bit...

Well, I don't know what you are planning to do with it. Most collectors items don't get a lot of
miles and are specifically held for their beautiful workmanship.

The colostomy incident was a seat post failure, not a fork problem.

Jobst Brandt [email protected] Palo Alto CA
 
J

Jay Beattie

Guest
"A Muzi" <[email protected]> wrote in message news:[email protected]...
> "Thomas Hood" <[email protected]> wrote in message
> news:[email protected]...
> > Just curiousity but could you explain what you mean by "abrupt
transition"
> > and "feathered"?
> >
> > "Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
> > internal lug of the crown that cannot be feathered to a gradual transition as an external
> > lug can."
> >
> > By abrupt transition I assume you meant that internal lug looked
like the
> > LCO4 shown here: http://www.ceeway.com/Fork-Crowns-2.htm
> > I.e. the end of the lug is perpendicular to the blades and straight.
> >
> > However it would appear the Cinelli crown's end is not like this:
> > http://www.ceeway.com/Fork-Crowns.htm The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX all
> > seem to
share
> > this. Do these not have 'internally feathered' ends or have I
> misunderstood
> > you?
> >
> > The reason I ask is that I have just aquired an almost new Mercian fillet-brazed reynolds 653
> > frame with said crown. Stunning
craftmanship;
> the
> > guy I bought it off had too much money to spend and had just
'upgraded' to
> a
> > giant carbon fibre compact!?! I'm not complaining he sold it to me
for £75
> > including a record f/mech and titanium seatpost. However after
reading
> your
> > 'colostomy' incident story I'm a bit wary of that bit....
>
>
> Most Mercians I've seen, as most British bikes with that style crown,
used a
> Canetti rather than the Cinelli crown. ( You may know them best from
Raleigh
> Professionals, Raleigh Competitions and Holdsworth Pros) Canetti
crowns are
> thinner across the top between the blade and column. Cinellis are
more
> arched viewed from the front. Cinellis are "waisted" when viewed from above, Canettis are not,
> there being a flat face across the front and
back.
> Canettis end more abruptly inside than the later Cinelli which is
shaped
> such that there is more penetration in front and back than in the
center of
> the blade.

Andrew, I was wondering if Jobst's problems weren't caused in part by over-cooking -- heating up a
big internal lug and forcing brass through a small seam. I understand the whole stress-riser thing
(and it certainly makes sense), but I used Cinelli full sloping crowns for years (and high mileage)
and never had a problem -- even a fork that was involved in a wall impact that resulted in the usual
kink in the down-tube but no damage to the fork. I recently broke a 25 year old set of forks with a
Cinelli semi-sloping crown, but then I had to drive my roof-rack mounted bike into a too low garage
to do it. -- Jay Beattie.
 
T

Thomas Hood

Guest
> Most Mercians I've seen, as most British bikes with that style crown, used
a
> Canetti rather than the Cinelli crown. ( You may know them best from
Raleigh
> Professionals, Raleigh Competitions and Holdsworth Pros) Canetti crowns
are
> thinner across the top between the blade and column. Cinellis are more arched viewed from the
> front. Cinellis are "waisted" when viewed from above, Canettis are not, there being a flat face
> across the front and
back.
> Canettis end more abruptly inside than the later Cinelli which is shaped such that there is more
> penetration in front and back than in the center
of
> the blade.
>
> --
> Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
>
>

Well not this one. Its definitely a Cinelli :) ...or should that be :-(

Thomas Hood
 
S

Scoochiro

Guest
[email protected] wrote in message news:<[email protected]>...
>
> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end abruptly
> (because no one can see this) and out of sight out of mind. However, fork blades fail in fatigue
> at this transition, breaking off after an insignificant life duration. As I said, I had tow of
> these failures and insisted on an external crown that was filed to have a zero thickness
> transition. This has worked for many more miles than any of my Cinelli forks survived.

How many miles constitute an "insignificant life duration"?
 
J

Jobst Brandt

Guest
K? Harper writes:

>> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end abruptly
>> (because no one can see this) and out of sight out of mind. However, fork blades fail in fatigue
>> at this transition, breaking off after an insignificant life duration. As I said, I had tow of
>> these failures and insisted on an external crown that was filed to have a zero thickness
>> transition. This has worked for many more miles than any of my Cinelli forks survived.

> How many miles constitute an "insignificant life duration"?

About 5000 miles.

Jobst Brandt [email protected] Palo Alto CA
 
S

Scoochiro

Guest
[email protected] wrote in message news:<[email protected]>...
> K? Harper writes:
>
> >> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
> >> abruptly (because no one can see this) and out of sight out of mind. However, fork blades fail
> >> in fatigue at this transition, breaking off after an insignificant life duration. As I said, I
> >> had tow of these failures and insisted on an external crown that was filed to have a zero
> >> thickness transition. This has worked for many more miles than any of my Cinelli forks
> >> survived.
>
> > How many miles constitute an "insignificant life duration"?
>
> About 5000 miles.
>

I'm interested in your observations on this, and I want to make sure that I've got your
statement clear: is it your experience that a Cinelli fully sloping crown can, and often does,
fail by breaking fork blades at or around 5000 miles? Did the ones you write of break at or near
that mileage?

Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
crowns are made to be ridden, and since they are an integral part of the steering/safety of a
bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
things are unreasonably hazardous?

Now, of course, just because something exists in the marketplace is no real evidence at all of its
safety, design wisdom, etc. That is obvious. But the Cinelli crown has been around a long time, a
lot of frames have been built using it, and if these facts resulted in a disproportionately large
number of breakages (and, presumably in many -- though not all -- cases, resulting injuries), then
wouldn't the tort system/products liability law force Cinelli to acknowledge a design defect?

I know that you don't like the crown, and I have no reason to debate the engineering basis for your
dislike. In terms of the design's drawbacks, I have to assume you are correct.

I'm just asking, is it as failure prone as you say (i.e., reasonable expectation that a reasonable
number of these things won't last over 5000 miles)?

Ken Harper
 
T

Tim Cain

Guest
"Scoochiro" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote in message
news:<[email protected]>...
> > K? Harper writes:
> >
> > >> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
> > >> abruptly (because no one can see this) and out of sight out of mind. However, fork blades
> > >> fail in fatigue at this transition, breaking off after an insignificant life duration. As I
> > >> said, I had tow of these failures and insisted on an external crown that was filed to have a
> > >> zero thickness transition. This has worked for many more miles than any of my Cinelli forks
> > >> survived.
> >
> > > How many miles constitute an "insignificant life duration"?
> >
> > About 5000 miles.
> >
>
> I'm interested in your observations on this, and I want to make sure that I've got your statement
> clear: is it your experience that a Cinelli fully sloping crown can, and often does, fail by
> breaking fork blades at or around 5000 miles? Did the ones you write of break at or near that
> mileage?
>
> Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
> be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
> things are unreasonably hazardous?
>

Part of this could be that very many bikes never see 500 miles usage, let alone 5000.

Tim.

---
Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.487 / Virus Database: 286 - Release Date: 01/06/03
 
J

Jay Beattie

Guest
"Scoochiro" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote in message
news:<[email protected]>...
> > K? Harper writes:
> >
> > >> The Cinelli crown has fairly thick lug extensions that go inside
the
> > >> fork blades and end abruptly (because no one can see this) and
out of
> > >> sight out of mind. However, fork blades fail in fatigue at this transition, breaking off
> > >> after an insignificant life duration.
As I
> > >> said, I had tow of these failures and insisted on an external
crown
> > >> that was filed to have a zero thickness transition. This has
worked
> > >> for many more miles than any of my Cinelli forks survived.
> >
> > > How many miles constitute an "insignificant life duration"?
> >
> > About 5000 miles.
> >
>
> I'm interested in your observations on this, and I want to make sure that I've got your statement
> clear: is it your experience that a Cinelli fully sloping crown can, and often does, fail by
> breaking fork blades at or around 5000 miles? Did the ones you write of break at or near that
> mileage?

I got way more than that out of mine. The whole bike was trashed in a car accident, rebuilt as a
commuter and then broke at the seat tube. The fork was alive until the end. It took the impact of
the car accident, transmitted it into the down tube which in turn kinked. I probably had a good 20K
on that bike. I think the fork may still be around somewhere.

> Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
> be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
> things are unreasonably hazardous?

Most people who have Cinelli full-sloping crowns clean their bikes so often that they would notice a
crack. I think a few of the De Rosas or Masis came with that crown -- or maybe it was the old
Raleigh Pro. Anyway, I saw one somewhere in the early '70s and had to have it on my super-fine
custom built frame. It was not spec'd on Huffys.

> Now, of course, just because something exists in the marketplace is no real evidence at all of its
> safety, design wisdom, etc. That is obvious. But the Cinelli crown has been around a long time, a
> lot of frames have been built using it, and if these facts resulted in a disproportionately large
> number of breakages (and, presumably in many -- though not all -- cases, resulting injuries), then
> wouldn't the tort system/products liability law force Cinelli to acknowledge a design defect?

Jobst has this Hulk thing going and breaks everything. For the usual schlub, the Cinelli full
sloping crown is plenty safe -- although you did not hear that from me and cannot rely on anything
that I say. It does have a built-in stress-riser, so it really is not the best design.

> I'm just asking, is it as failure prone as you say (i.e., reasonable expectation that a reasonable
> number of these things won't last over 5000 miles)?

Get with it man, this is the new age of disposable bicycles and components. Read your warranty (or,
more accurately, your warranty disclaimer). -- Jay Beattie.
 
R

Richard Sachs

Guest
They are Cinelli "style" crowns...

Cinelli doesn't make them, and hasn't since the early 70s. Back then, the industry "copied" the look
and many firms produced a look-a-like crown for all sorts of blades.

Cinelli crowned forks graced Cinelli bicycles. Tens of thousands of forks, made to look similarly,
are just that: copies. No need to worry about suits nor Cinelli's "place" in all this!

e-RICHIE www.richardsachs.com



[email protected] (Scoochiro) wrote in message
news:<[email protected]>...
> [email protected] wrote in message
> news:<[email protected]>...
> > K? Harper writes:
> >
> > >> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
> > >> abruptly (because no one can see this) and out of sight out of mind. However, fork blades
> > >> fail in fatigue at this transition, breaking off after an insignificant life duration. As I
> > >> said, I had tow of these failures and insisted on an external crown that was filed to have a
> > >> zero thickness transition. This has worked for many more miles than any of my Cinelli forks
> > >> survived.
>
> > > How many miles constitute an "insignificant life duration"?
> >
> > About 5000 miles.
> >
>
> I'm interested in your observations on this, and I want to make sure that I've got your statement
> clear: is it your experience that a Cinelli fully sloping crown can, and often does, fail by
> breaking fork blades at or around 5000 miles? Did the ones you write of break at or near that
> mileage?
>
> Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
> be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
> things are unreasonably hazardous?
>
> Now, of course, just because something exists in the marketplace is no real evidence at all of its
> safety, design wisdom, etc. That is obvious. But the Cinelli crown has been around a long time, a
> lot of frames have been built using it, and if these facts resulted in a disproportionately large
> number of breakages (and, presumably in many -- though not all -- cases, resulting injuries), then
> wouldn't the tort system/products liability law force Cinelli to acknowledge a design defect?
>
> I know that you don't like the crown, and I have no reason to debate the engineering basis for
> your dislike. In terms of the design's drawbacks, I have to assume you are correct.
>
> I'm just asking, is it as failure prone as you say (i.e., reasonable expectation that a reasonable
> number of these things won't last over 5000 miles)?
>
>
> Ken Harper
 
J

Jobst Brandt

Guest
Ken Harper writes:

>>>> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
>>>> abruptly (because no one can see this) and out of sight out of mind. However, fork blades fail
>>>> in fatigue at this transition, breaking off after an insignificant life duration. As I said, I
>>>> had tow of these failures and insisted on an external crown that was filed to have a zero
>>>> thickness transition. This has worked for many more miles than any of my Cinelli forks
>>>> survived.

>>> How many miles constitute an "insignificant life duration"?

>> About 5000 miles.

> I'm interested in your observations on this, and I want to make sure that I've got your statement
> clear: is it your experience that a Cinelli fully sloping crown can, and often does, fail by
> breaking fork blades at or around 5000 miles? Did the ones you write of break at or near that
> mileage?

I did not say that. I responded to the question above. I don't know how long such forks last on the
average and under whose use.

> Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
> be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
> things are unreasonably hazardous?

It's much like the disc brake issue being debated in this news group. There is a distinct
probability of failure but not a predictable one. The point is that this fork crown weighs about
twice what far more durable ones do and it has a basic flaw. Steel frames have had shaped lugs to
prevent stress concentrations from their earliest days. The sloping fork crown is a great leap
backwards in that respect.

Jobst Brandt [email protected] Palo Alto CA
 
A

A Muzi

Guest
> > "Thomas Hood" <[email protected]> wrote in message
> > news:[email protected]...
> > > Just curiousity but could you explain what you mean by "abrupt
> transition"
> > > and "feathered"?
> > >
> > > "Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
> > > internal lug of the crown that cannot be feathered to a gradual transition as an external lug
> > > can."
> > >
> > > By abrupt transition I assume you meant that internal lug looked
> like the
> > > LCO4 shown here: http://www.ceeway.com/Fork-Crowns-2.htm
> > > I.e. the end of the lug is perpendicular to the blades and straight.
> > >
> > > However it would appear the Cinelli crown's end is not like this:
> > > http://www.ceeway.com/Fork-Crowns.htm The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX
> > > all seem to
> share
> > > this. Do these not have 'internally feathered' ends or have I
> > misunderstood
> > > you?
> > >
> > > The reason I ask is that I have just aquired an almost new Mercian fillet-brazed reynolds 653
> > > frame with said crown. Stunning
> craftmanship;
> > the
> > > guy I bought it off had too much money to spend and had just
> 'upgraded' to
> > a
> > > giant carbon fibre compact!?! I'm not complaining he sold it to me
> for £75
> > > including a record f/mech and titanium seatpost. However after
> reading
> > your
> > > 'colostomy' incident story I'm a bit wary of that bit....

> "A Muzi" <[email protected]> wrote in message news:[email protected]...
> > Most Mercians I've seen, as most British bikes with that style crown,
> used a
> > Canetti rather than the Cinelli crown. ( You may know them best from
> Raleigh
> > Professionals, Raleigh Competitions and Holdsworth Pros) Canetti
> crowns are
> > thinner across the top between the blade and column. Cinellis are
> more
> > arched viewed from the front. Cinellis are "waisted" when viewed from above, Canettis are not,
> > there being a flat face across the front and
> back.
> > Canettis end more abruptly inside than the later Cinelli which is
> shaped
> > such that there is more penetration in front and back than in the
> center of
> > the blade.

"Jay Beattie" <[email protected]> wrote in message news:[email protected]...
> Andrew, I was wondering if Jobst's problems weren't caused in part by over-cooking -- heating up a
> big internal lug and forcing brass through a small seam. I understand the whole stress-riser thing
> (and it certainly makes sense), but I used Cinelli full sloping crowns for years (and high
> mileage) and never had a problem -- even a fork that was involved in a wall impact that resulted
> in the usual kink in the down-tube but no damage to the fork. I recently broke a 25 year old set
> of forks with a Cinelli semi-sloping crown, but then I had to drive my roof-rack mounted bike into
> a too low garage to do it. -- Jay Beattie.

Are you speculating about brazing errors in a frame we've never seen, built by someone we do not
know and cannot even name? That is silly.

However, how many riders log as many miles as Jobst? In severe conditions like long descents
regularly at speed? There may not have been anything "wrong" with his forks under a different rider
who rides 500 miles per year and hangs it on the wall a lot.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
 
D

David L. Johnso

Guest
On Mon, 02 Jun 2003 23:41:25 +0100, Tim Cain wrote:

> Part of this could be that very many bikes never see 500 miles usage, let alone 5000.

Well, a lot of Cinellis saw more miles than that. But most of those miles were a long time ago,
possibly predating the rush to litigation.

--

David L. Johnson

__o | A mathematician is a machine for turning coffee into theorems. _`\(,_ | -- Paul Erdos
(_)/ (_) |
 
M

Mike Jacoubowsk

Guest
> It's much like the disc brake issue being debated in this news group. There is a distinct
> probability of failure but not a predictable one. The point is that this fork crown weighs about
> twice what far more durable ones do and it has a basic flaw. Steel frames have had shaped lugs to
> prevent stress concentrations from their earliest days. The sloping fork crown is a great leap
> backwards in that respect.

Rather than calling something out of the past a "great leap backwards" I'd call it an old design
that has flaws and has been greatly improved upon.

As far as I know, that design is no longer in use today, and your "great leap backwards" might be
misread by some.

In the meantime, guess I'd better go check out my own Iron Pig (1973 Cinelli) that has well in
excess of 50k miles on it... including some challenging rides in the Santa Cruz Mountains with some
guy who knew all the secret roads & trails and streams to drink out of.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
 
G

Gary Young

Guest
[email protected] (Scoochiro) wrote in message
news:<[email protected]>...
> [email protected] wrote in message
> news:<[email protected]>...
> > K? Harper writes:
> >
> > >> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
> > >> abruptly (because no one can see this) and out of sight out of mind. However, fork blades
> > >> fail in fatigue at this transition, breaking off after an insignificant life duration. As I
> > >> said, I had tow of these failures and insisted on an external crown that was filed to have a
> > >> zero thickness transition. This has worked for many more miles than any of my Cinelli forks
> > >> survived.
>
> > > How many miles constitute an "insignificant life duration"?
> >
> > About 5000 miles.
> >
>
> I'm interested in your observations on this, and I want to make sure that I've got your statement
> clear: is it your experience that a Cinelli fully sloping crown can, and often does, fail by
> breaking fork blades at or around 5000 miles? Did the ones you write of break at or near that
> mileage?
>
> Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't Cinelli
> be fending off lawsuits left and right, presumably with your testimony as Exhibit A on why these
> things are unreasonably hazardous?
>
> Now, of course, just because something exists in the marketplace is no real evidence at all of its
> safety, design wisdom, etc. That is obvious. But the Cinelli crown has been around a long time, a
> lot of frames have been built using it, and if these facts resulted in a disproportionately large
> number of breakages (and, presumably in many -- though not all -- cases, resulting injuries), then
> wouldn't the tort system/products liability law force Cinelli to acknowledge a design defect?
>
> I know that you don't like the crown, and I have no reason to debate the engineering basis for
> your dislike. In terms of the design's drawbacks, I have to assume you are correct.
>
> I'm just asking, is it as failure prone as you say (i.e., reasonable expectation that a reasonable
> number of these things won't last over 5000 miles)?
>
I don't think personal injury lawyers pay much attention to bicycles. Sure, there are some lawyers
who advertise in the back of Velonews, etc., but they're probably suing drivers in most instances.
If lawyers were constantly breathing down the necks of the bicycle industry, do you think we would
be seeing ever lighter components, including things like titanium pedal spindles that we know break
in fair numbers? How many decades did Campagnolo produce cranks that were prone to breaking? How
many boutique companies come and go, putting ill-thought-out products on the market and then
disappearing from view in a few summers?

Personal injury lawyers are looking for deep pockets, quick turnaround, and the most bang for the
buck (in other words, the biggest recovery given their investment in time and resources). Most
bicycle accidents not involving cars are fairly minor compared to automobile accidents (and that
automatically puts a limit on how much you can collect). If it involves a car, it's easier to go
after the driver's insurer. Think about the effort involved in proving that Cinelli-style fork
crowns are more dangerous than other designs. First, you'd have to get Cinelli and other fork makers
to cough up a lot of proprietary data -- no mean effort. I believe it took months or years before
lawyers suing Ford/Firestone realized that there was a pattern to SUV accidents. Ford and Firestone
certainly weren't spreading the word.

On the whole, even the biggest pockets in the bicycle world are small potatoes compared to the
companies personal injury lawyers usually target.

Yes, I'm aware that there are lawsuits against bike manufacturers and that some people have
collected on frivolous claims. But I haven't seen that translate into any impact on bicycle design
(with the possible exception of lawyer lips, and that was probably adopted as much because it was
virtually costless as for any other reason -- just like you see warning stickers on some products
instead of a redesign). I suspect lawsuits have their biggest impact on the bicycle industry in the
form of higher insurance premiums, and little else.

Have you been following the thread on James Annan's discovery regarding disk brakes? Perhaps
there's something going on behind the scenes, but it looks like the industry wants to bury its head
in the sand.

I'm probably in the minority here, but I think the bicycle consumer might actually benefit from some
well-targeted lawsuits against bicycle manufacturers. I don't expect to see it anytime soon, because
the smart lawyers have bigger fish to fry.

I'm not entirely hopeless about the situation though. I do think it's heartening that people like
James Annan and the contributors to this newsgroup are trying to uncover patterns that the bicycle
manufacturers are indifferent to or too lacking in resources to uncover. If we publicize these
things, the manufacturers (or, perhaps more importantly, their insurers) will probably begin to
take notice.
 
S

Scoochiro

Guest
[email protected] wrote in message news:<[email protected]>...
> Ken Harper writes:
>
> >>>> The Cinelli crown has fairly thick lug extensions that go inside the fork blades and end
> >>>> abruptly (because no one can see this) and out of sight out of mind. However, fork blades
> >>>> fail in fatigue at this transition, breaking off after an insignificant life duration. As I
> >>>> said, I had tow of these failures and insisted on an external crown that was filed to have a
> >>>> zero thickness transition. This has worked for many more miles than any of my Cinelli forks
> >>>> survived.
>
> >>> How many miles constitute an "insignificant life duration"?
>
> >> About 5000 miles.
>
> > I'm interested in your observations on this, and I want to make sure that I've got your
> > statement clear: is it your experience that a Cinelli fully sloping crown can, and often does,
> > fail by breaking fork blades at or around 5000 miles? Did the ones you write of break at or near
> > that mileage?
>
> I did not say that. I responded to the question above. I don't know how long such forks last on
> the average and under whose use.

In deference to Richard, I will duly note that these are Cinelli-style crowns.

(And I know that Richard has expressed some fondness for these types of crowns in the past. Richard:
did you find there to be an unacceptable failure rate, or did your view of aesthetic issues change,
or did something else cause you to adopt your now well-recognized own design?)

Re Jobst's observations, I was just wondering if you had any basis to claim a "5000 mile life
duration"? It would seem that you don't. Or it would seem that a "life duration" is something other
than the point at which a fork crown fails (which is rather surprising, since these concepts seem
quite synonymous).

So, again granting that this is not the best designed fork crown, why wouldn't it have been just as
accurate to claim a 10,000 mile "life duration"? If you don't know how long such forks last on the
average and under whose use, then what would make the 5,000 mile number any more or less valid than
a 25,000 mile number?

I mean, I guess the whole point of my discussion is that you are well respected for your engineering
knowledge of bicycles. Thus, I take your observations seriously, and even more so when there is a
failure issue regarding something like a fork cown.

So, the real question is, from my point of view, has your engineering knowledge been applied in a
methodical way to reach the 5,000 mile number, or was that a dislike of the design coupled with a
guess? Which is fine, too; I've certainly got my guesses on things as well.

But a statement like "5000 mile life duration" is going to suggest to me, and the OP, at least, that
this is not a particularly good bike to ride, at least not often.

Is the following a valid conclusion from your statement: if I have a frame with at least 5,000 miles
on it, and if it has such a crown, then I've already exceeded the crown's life duration, and I just
might reasonably expect a failure at any point now?

Ken Harper
 
J

Jay Beattie

Guest
"A Muzi" <[email protected]> wrote in message news:[email protected]...
> > > "Thomas Hood" <[email protected]> wrote in
message
> > > news:[email protected]...
> > > > Just curiousity but could you explain what you mean by "abrupt
> > transition"
> > > > and "feathered"?
> > > >
> > > > "Cinelli sloping crowns....are failure prone at the abrupt transition from fork blade to the
> > > > internal lug of the crown that cannot be feathered to a gradual transition as an external
> > > > lug
can."
> > > >
> > > > By abrupt transition I assume you meant that internal lug looked
> > like the
> > > > LCO4 shown here: http://www.ceeway.com/Fork-Crowns-2.htm
> > > > I.e. the end of the lug is perpendicular to the blades and
straight.
> > > >
> > > > However it would appear the Cinelli crown's end is not like
this:
> > > > http://www.ceeway.com/Fork-Crowns.htm The Cinelli SCA, Everest C60, C61A, C63, Columbus MAX
> > > > all seem
to
> > share
> > > > this. Do these not have 'internally feathered' ends or have I
> > > misunderstood
> > > > you?
> > > >
> > > > The reason I ask is that I have just aquired an almost new
Mercian
> > > > fillet-brazed reynolds 653 frame with said crown. Stunning
> > craftmanship;
> > > the
> > > > guy I bought it off had too much money to spend and had just
> > 'upgraded' to
> > > a
> > > > giant carbon fibre compact!?! I'm not complaining he sold it to
me
> > for £75
> > > > including a record f/mech and titanium seatpost. However after
> > reading
> > > your
> > > > 'colostomy' incident story I'm a bit wary of that bit....
>
> > "A Muzi" <[email protected]> wrote in message news:[email protected]...
> > > Most Mercians I've seen, as most British bikes with that style
crown,
> > used a
> > > Canetti rather than the Cinelli crown. ( You may know them best
from
> > Raleigh
> > > Professionals, Raleigh Competitions and Holdsworth Pros) Canetti
> > crowns are
> > > thinner across the top between the blade and column. Cinellis
are
> > more
> > > arched viewed from the front. Cinellis are "waisted" when viewed
from
> > > above, Canettis are not, there being a flat face across the front
and
> > back.
> > > Canettis end more abruptly inside than the later Cinelli which is
> > shaped
> > > such that there is more penetration in front and back than in the
> > center of
> > > the blade.
>
>
> "Jay Beattie" <[email protected]> wrote in message
> news:[email protected]...
> > Andrew, I was wondering if Jobst's problems weren't caused in part
by
> > over-cooking -- heating up a big internal lug and forcing brass
through
> > a small seam. I understand the whole stress-riser thing (and it certainly makes sense), but I
> > used Cinelli full sloping crowns for
years
> > (and high mileage) and never had a problem -- even a fork that was involved in a wall impact
> > that resulted in the usual kink in the down-tube but no damage to the fork. I recently broke a
> > 25 year old
set
> > of forks with a Cinelli semi-sloping crown, but then I had to drive
my
> > roof-rack mounted bike into a too low garage to do it. -- Jay
Beattie.
>
>
> Are you speculating about brazing errors in a frame we've never seen,
built
> by someone we do not know and cannot even name? That is silly.

Actually, I was wondering whether this was a problematic joint -- one prone to overheating. Silly or
not, some lugs are harder to braze than others, and it seems to me that the internal plugs would be
a big heat sink.

> However, how many riders log as many miles as Jobst? In severe
conditions
> like long descents regularly at speed? There may not have been
anything
> "wrong" with his forks under a different rider who rides 500 miles
per year
> and hangs it on the wall a lot.

Hell, in the '70s and 80s, I logged similar mileages living in the same neighborhood riding a bike
with a full-sloping Cinelli crown -- and about 25lbs heavier than Jobst. 5,000 miles is not that
far, regardless of the descents or the breaking forces (which, as I understand it, Jobst used
sparingly). For a fairly devoted Master or Cat 3 in the Santa Clara Valley in the '70s and 80s, that
would be about one racing season. This is why I thought there might have been some contribution to
the failure from another source besides the design. -- Jay Beattie.
 
J

Jay Beattie

Guest
"Gary Young" <[email protected]> wrote in message
news:[email protected]...
> [email protected] (Scoochiro) wrote in message
news:<[email protected]>...
> > [email protected] wrote in message
news:<[email protected]>...
> > > K? Harper writes:
> > >
> > > >> The Cinelli crown has fairly thick lug extensions that go
inside the
> > > >> fork blades and end abruptly (because no one can see this) and
out of
> > > >> sight out of mind. However, fork blades fail in fatigue at
this
> > > >> transition, breaking off after an insignificant life duration.
As I
> > > >> said, I had tow of these failures and insisted on an external
crown
> > > >> that was filed to have a zero thickness transition. This has
worked
> > > >> for many more miles than any of my Cinelli forks survived.
> >
> > > > How many miles constitute an "insignificant life duration"?
> > >
> > > About 5000 miles.
> > >
> >
> > I'm interested in your observations on this, and I want to make sure that I've got your
> > statement clear: is it your experience that a Cinelli fully sloping crown can, and often does,
> > fail by breaking
fork
> > blades at or around 5000 miles? Did the ones you write of break at
or
> > near that mileage?
> >
> > Maybe I have misconstrued your statement but, if not, then I find it hard to believe. Since fork
> > crowns are made to be ridden, and since they are an integral part of the steering/safety of a
> > bicycle, and since we have no shortage of plaintiffs lawyers in this country, why wouldn't
> > Cinelli be fending off lawsuits left and right, presumably with your testimony as Exhibit A on
> > why these things are
unreasonably
> > hazardous?
> >
> > Now, of course, just because something exists in the marketplace is
no
> > real evidence at all of its safety, design wisdom, etc. That is obvious. But the Cinelli crown
> > has been around a long time, a lot
of
> > frames have been built using it, and if these facts resulted in a disproportionately large
> > number of breakages (and, presumably in
many
> > -- though not all -- cases, resulting injuries), then wouldn't the tort system/products
> > liability law force Cinelli to acknowledge a design defect?
> >
> > I know that you don't like the crown, and I have no reason to debate the engineering basis for
> > your dislike. In terms of the design's drawbacks, I have to assume you are correct.
> >
> > I'm just asking, is it as failure prone as you say (i.e., reasonable expectation that a
> > reasonable number of these things won't last over 5000 miles)?
> >
> I don't think personal injury lawyers pay much attention to bicycles. Sure, there are some lawyers
> who advertise in the back of Velonews, etc., but they're probably suing drivers in most instances.
> If lawyers were constantly breathing down the necks of the bicycle industry, do you think we would
> be seeing ever lighter components, including things like titanium pedal spindles that we know
> break in fair numbers? How many decades did Campagnolo produce cranks that were prone to breaking?
> How many boutique companies come and go, putting ill-thought-out products on the market and then
> disappearing from view in a few summers?

Actually, PI lawyers love a good bicycle-related products liability law suit. They do not present
the same problems as an auto versus bicycle case (drivers are jurors) and are usually subject to
much higher insurance limits. The "problem" is that bicycles and components do not often break in a
way that causes serious injury. I have broken four or five cranks, and never so much as fell off my
bike or smashed my privates.

> Personal injury lawyers are looking for deep pockets, quick turnaround, and the most bang for the
> buck (in other words, the biggest recovery given their investment in time and resources). Most
> bicycle accidents not involving cars are fairly minor compared to automobile accidents (and that
> automatically puts a limit on how much you can collect). If it involves a car, it's easier to go
> after the driver's insurer. Think about the effort involved in proving that Cinelli-style fork
> crowns are more dangerous than other designs. First, you'd have to get Cinelli and other fork
> makers to cough up a lot of proprietary data -- no mean effort. I believe it took months or years
> before lawyers suing Ford/Firestone realized that there was a pattern to SUV accidents. Ford and
> Firestone certainly weren't spreading the word.

This would be an easy strict liability case against Cinelli or the American distributor. One
expert, maybe two, to testify that the internal lug creates a stress-riser which results in the
early failure of the fork. Assuming that there is a pattern of failures, go for punitive damages.
Put those Italians out of business ladies and gentlemen. Remember Mussolini? Remeber the Fiat? I
am outraged!

<snip>

> Yes, I'm aware that there are lawsuits against bike manufacturers and that some people have
> collected on frivolous claims. But I haven't seen that translate into any impact on bicycle design
> (with the possible exception of lawyer lips, and that was probably adopted as much because it was
> virtually costless as for any other reason -- just like you see warning stickers on some products
> instead of a redesign). I suspect lawsuits have their biggest impact on the bicycle industry in
> the form of higher insurance premiums, and little else.

Design changes are frequently made to address consumer complaints and in response to law suits.
Changes that come to mind that were driven in part by law suits include the demise of the 5mm cap
screw/fork crown on mountain bikes; gussets on Al frames, wheel retention devices, endless warning
labels and disclaimers in manuals and handbooks, reflectors, lights (although this has not taken off
after the Derby case). Think of all the recalled products. The CPSC and SNELL/ANSI have requirements
which may result from incident reports or complaints that also turned into lawsuits.

<snip>

> I'm not entirely hopeless about the situation though. I do think it's heartening that people like
> James Annan and the contributors to this newsgroup are trying to uncover patterns that the bicycle
> manufacturers are indifferent to or too lacking in resources to uncover. If we publicize these
> things, the manufacturers (or, perhaps more importantly, their insurers) will probably begin to
> take notice.

I doubt the domestic manufacturers are indifferent. I have spent a lot of time representing several
domestic manufacturers and found that they did extensive and expensive testing on their products.
There are some foreign OEM manufacturers who are less diligent, IMO, and absent close oversight from
the American customer, may come up with a dangerous look-alike product. -- Jay Beattie.
 
J

Jobst Brandt

Guest
Gary Young writes:

> I don't think personal injury lawyers pay much attention to bicycles. Sure, there are some lawyers
> who advertise in the back of Velo news, etc., but they're probably suing drivers in most
> instances. If lawyers were constantly breathing down the necks of the bicycle industry, do you
> think we would be seeing ever lighter components, including things like titanium pedal spindles
> that we know break in fair numbers? How many decades did Campagnolo produce cranks that were prone
> to breaking? How many boutique companies come and go, putting ill-thought-out products on the
> market and then disappearing from view in a few summers?

I think you hypothesize about law suits of which you are apparently unaware. I have testified as an
expert witness in defense of the bicycle industry against many weird claims. In most of these there
have been other 'expert' witnesses who will testify to anything a plaintiff claims. I have testified
against such experts in most cases of which none had any merit. These cases are generally taken
under contingency and after I have shown that the claims are unsupportable, cases are generally
settled, everyone getting a little payoff including the plaintiff (liar) and the game starts over.
In contrast, most Japanese firms demand a judgment even if the legal fees are greater, in the
interest of setting precedence. I favor that approach.

Jobst Brandt [email protected] Palo Alto CA
 
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