The frame that wouldn't break

I have in front of me the april 2004 bicycling magazine. It has an article about what cannondale
does to test its frames. If I remember correctly Shaq went to his local cannondale dealer and sat on
a cannondale and broke the seat post. So cannondale offered to build him a custom frame. Cannondale
built three frames an tested one of them and it wouldn't at 3200 lbs. Their typical frame breaks at
1200 lbs. Now if Shaq weighs 320 lbs then the typical cannondale is designed for a 120 lb person
320*1200/3200=120. Now I never actually broke my cannondale frame however there were three dents in
the dropouts two caused by the weight on the bike and one caused by the chain pull. After about 6000
miles the dent caused by the chain pull was so bad the tire rubbed the frame. Cannondale also talks
about how their legal department tries to prove that broken frames are never cannondales fault but
they also talk about probabalistic failure thus admitting that frame failures are inevitable.You
have been warned.

 

[email protected] (charles ramsey) wrote:

> I have in front of me the april 2004 bicycling magazine. It has an article about what cannondale
> does to test its frames. If I remember correctly Shaq went to his local cannondale dealer and sat
> on a cannondale and broke the seat post. So cannondale offered to build him a custom frame.
> Cannondale built three frames an tested one of them and it wouldn't at 3200 lbs. Their typical
> frame breaks at 1200 lbs. Now if Shaq weighs 320 lbs then the typical cannondale is designed for a
> 120 lb person 320*1200/3200=120. Now I never actually broke my cannondale frame however there were
> three dents in the dropouts two caused by the weight on the bike and one caused by the chain pull.
> After about 6000 miles the dent caused by the chain pull was so bad the tire rubbed the frame.
> Cannondale also talks about how their legal department tries to prove that broken frames are never
> cannondales fault but they also talk about probabalistic failure thus admitting that frame
> failures are inevitable.You have been warned.

Charles, I politely suggest that you review some basic materials science before you condemn
Connondale's frames.

Aluminum has no fatigue limit which means that all aluminum frames, or aluminum airplanes, cars or
anythings, will fail given enough load cycles. Cannondale's frames do indeed break; it would require
repealing some physical laws for it to be otherwise.

You can be sure that engineers have contemplated this fact, as well as their legal department. For
the vast majority of users, the frames never see enough load cycles to break, and for the
relatively few that do break as a result of normal use or improper welding or heat treating are
replaced under warranty.

(I don't own a Cannondale and have no connection with the company)

I am interested in the "dents" that you have in your dropouts. Those are made of thick plate and
would not be dented by "chain pull" because such dents would need a force large enough to break the
chain, a force large enough to pretzel the whole rear triangle. My guess would be that you are
seeing wear caused by the axle moving in the dropouts, such as would be caused by installation of
the wheel or improperly tightened QR.

Can you post any pictures?

--
Ted Bennett Portland OR

 

Does Cannondale warranttee their aluminum frames for life? I have an aluminum Giant and their
warranttee is for only five years. Thanks - BUBBA

charles ramsey <[email protected]> wrote in message
news:[email protected]...
> I have in front of me the april 2004 bicycling magazine. It has an article about what cannondale
> does to test its frames. If I remember correctly Shaq went to his local cannondale dealer and sat
> on a cannondale and broke the seat post. So cannondale offered to build him a custom frame.
> Cannondale built three frames an tested one of them and it wouldn't at 3200 lbs. Their typical
> frame breaks at 1200 lbs. Now if Shaq weighs 320 lbs then the typical cannondale is designed for a
> 120 lb person 320*1200/3200=120. Now I never actually broke my cannondale frame however there were
> three dents in the dropouts two caused by the weight on the bike and one caused by the chain pull.
> After about 6000 miles the dent caused by the chain pull was so bad the tire rubbed the frame.
> Cannondale also talks about how their legal department tries to prove that broken frames are never
> cannondales fault but they also talk about probabalistic failure thus admitting that frame
> failures are inevitable.You have been warned.

 

"charles ramsey" <[email protected]> wrote in message
news:[email protected]...
> I have in front of me the april 2004 bicycling magazine.

You know, if you cancel your subscription to Bicycling, it will keep coming -- forever, at no
charge. It is amazing. For nothing, Bicycling is worth every penny.

<snip>

> Now I never actually broke my cannondale frame however there
were three dents in the dropouts two
> caused by the weight on the bike and one caused by the chain
pull.
> After about 6000 miles the dent caused by the chain pull was so
bad
> the tire rubbed the frame. Cannondale also talks about how
their legal
> department tries to prove that broken frames are never
cannondales
> fault but they also talk about probabalistic failure thus
admitting
> that frame failures are inevitable.You have been warned.

I suspect this is a troll -- but I'll take the bait. Failure is inevitable if you put a frame in a
monstrous hydraulic press and compress it a few thousand times. Luckily, I do not ride like a
monstrous hydraulic press. Also, I do not know what you are talking about when you refer to drop-out
denting. Perhaps you could enlighten us. -- Jay Beattie.

 

Gotta love that. Thanks - BUBBA

Jay Beattie <[email protected]> wrote in message news:[email protected]...
>
> "charles ramsey" <[email protected]> wrote in message
> news:[email protected]...
> > I have in front of me the april 2004 bicycling magazine.
>
> You know, if you cancel your subscription to Bicycling, it will keep coming -- forever, at no
> charge. It is amazing. For nothing, Bicycling is worth every penny.
>
> <snip>
>
> > Now I never actually broke my cannondale frame however there
> were three dents in the dropouts two
> > caused by the weight on the bike and one caused by the chain
> pull.
> > After about 6000 miles the dent caused by the chain pull was so
> bad
> > the tire rubbed the frame. Cannondale also talks about how
> their legal
> > department tries to prove that broken frames are never
> cannondales
> > fault but they also talk about probabalistic failure thus
> admitting
> > that frame failures are inevitable.You have been warned.
>
> I suspect this is a troll -- but I'll take the bait. Failure is inevitable if you put a frame in a
> monstrous hydraulic press and compress it a few thousand times. Luckily, I do not ride like a
> monstrous hydraulic press. Also, I do not know what you are talking about when you refer to drop-
> out denting. Perhaps you could enlighten us. -- Jay Beattie.
>

 

charles ramsey wrote:

> I have in front of me the april 2004 bicycling magazine. It has an article about what cannondale
> does to test its frames. If I remember correctly Shaq went to his local cannondale dealer and sat
> on a cannondale and broke the seat post. So cannondale offered to build him a custom frame.
> Cannondale built three frames an tested one of them and it wouldn't at 3200 lbs. Their typical
> frame breaks at 1200 lbs. Now if Shaq weighs 320 lbs then the typical cannondale is designed for a
> 120 lb person 320*1200/3200=120.

It must be nice to live in such a simple world!

They were talking about frontal impact tests, a very unusual loading situation. Do you _really_
think the force to break a frame in that situation is somehow directly proportional to intended
rider weight??

> Now I never actually broke my cannondale frame however there were three dents in the dropouts two
> caused by the weight on the bike and one caused by the chain pull. After about 6000 miles the
> dent caused by the chain pull was so bad the tire rubbed the frame.

Let me guess. You were Just Riding Along, right? ;-)

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]

 

"Jay Beattie" <[email protected]> brightened my day with his
incisive wit when in news:[email protected] he conjectured
that:

>
> "charles ramsey" <[email protected]> wrote in message
> news:[email protected]...
>> I have in front of me the april 2004 bicycling magazine.
>
> You know, if you cancel your subscription to Bicycling, it will keep coming -- forever, at no
> charge. It is amazing. For nothing, Bicycling is worth every penny.
>

ha. Same happened to me. I got to feel guilty but it took me 2 years to convince them to stop
sending me free copies. Truly amazing.

 

"Jay Beattie" <[email protected]> wrote in message news:<[email protected]>...

[snip]

> Also, I do not know what you are talking about when you refer to drop-out denting. Perhaps you
> could enlighten us. -- Jay Beattie.

Dear Jay,

Drop-out denting might mean denting in the drop-out flange's normally smooth profile, as if the axle
had been driven upward or backward and dented the metal:
____________________
dent \ __ \ __________/ \____ \ \ \ \ \ \_ \ axle \ \ dent _/ / / / ____________/ / / /
\_______________/

As always, all dimensions and angles are accurate to be used as machining blueprints.

Carl Fogel

 

Sorry folks I had extreem dificulty posting that article and I had to leave some things out. The
article mentions just riding along failures this topic is too important to be buried here and I hope
someone will start a thread on it. Shaq broke the seatpost by just sitting on it this is a just
riding along failure riding stresses are easyly twice on a seat post so Shaq would have broke a
seatpost twice as strong on his first ride. Sorry I dont have any pictures my bike shop broke a tool
trying to remove the bottom bracket it seams that aluminum oxide has ten times the volume of
aluminum so I left the bike outside and it was eventually stolen. When I bought the bike used I
noticed the dropout was slightly dented so I instaled an axle 5mm longer they were 8mm thick so
there was room. The situation is worse now the right dropout is thinner to make room for a
replacable derailer hanger.

 

On the frame builders web site they talk about how all the schwinn paramounts used the same guage
tubing on all sizes do you think the mass producers do any different? When I broke my schwinn
traveler in 1981 I was told it was normal wear and tear and was not covered. In one of my favorite
books atlas of fatigue curves by Howard Boyer I was struck by how simular all the curves were at one
million cycles say a wheel with one thousand miles on it a 10% increase in stress will cut the life
of the product in half. One titanium builder says he will not use horizonal dropouts because the
quick release is not hard enough to grip titanium. Adults who use 3mm thick dropouts damage the axle
so it has to be chased to remove the cone. Has anyone ever seen an aluminum bike with horizonal
dropouts? Perhapes the dropouts are to soft to hold a quick release. Carl drew a good picture only
my dropouts were vertical.