Sheared off pedal - How's that happen?

I discovered the hard way yesterday that I should be concerned about
possibility that the pedals on my bike might shear right off in the
middle of a ride. While crossing a major intersection and standing on
the pedals to accelerate after being at a complete stop the right
pedal of my Look Keo Sprints sheared straight off just as I passed the
traffic throwning me face first into the asphalt. It happened so fast
I never perceived the going down portion of this. One second I'm up
and a nano second latter my head and face do a seven-beat stacatto
drum riff on the asphalt. Major thanks to the lady that stopped in her
car and helped me. Also the police and rescue squad folks. A cop was
on scene in mere seconds and the ambulance in less that two minutes.
Amazing nothing broken on me. I need a Phantom of the Opera mask for a
few weeks and Advil is my best friend. The bike was not as luckly as
me. Major damage to handelbars, computer, sunglass, helmet, etc.

To the question. How the hell can a $150 pare of so call high
technology pedals with chrom-molly axels just shear off right at the
crank? These guys are just less than a year old. Have nearly 5,000
miles on them. They were attached to my Lemond Maillot Jaune. Not any
more. Ain't going to trust life and limb to those pedals any more.
Does anyone know if there is any history here? What would make this
happen?

"HazeRider" wrote: (clip) To the question. How the hell can a $150 pare of
so call high
technology pedals with chrom-molly axels just shear off right at the
crank? (clip)
^^^^^^^^^^^^^^^^^^^^^^
I think you should send a picture of the pedal and a picture of your face to
the manufacturer and see what they say. DON'T SEND THEM THE PEDAL.

I'd should say: do not in any case accept this!

This may not have happened!

I don't know exactly how this works in the US, but I suggest to hold
your LBS, where you bought it, responsible for all the damage to you
and your bike.

Do this by registered wrting accompanied by a witness statement as from
the police officers present and pictures of the pedal/axle.

I agree with first replier's suggestion *not* to send the pedal itself.

Only accept inspection by certified third party experts.

It might help to have a friend/collegue with knowledge about metal
failure mechanisms who can inspect and write a short report, attached
to your letter.

Can you publish some pic's of the fracture?

Success and pls keep us informed about proceedings!

Martin (NL)

On Apr 28, 12:43 pm, HazeRider wrote:
I discovered the hard way yesterday that I should be concerned about
possibility that the pedals on my bike might shear right off in the
middle of a ride. While crossing a major intersection and standing on
the pedals to accelerate after being at a complete stop the right
pedal of my Look Keo Sprints sheared straight off just as I passed the
traffic throwning me face first into the asphalt. It happened so fast
I never perceived the going down portion of this. One second I'm up
and a nano second latter my head and face do a seven-beat stacatto
drum riff on the asphalt. Major thanks to the lady that stopped in her
car and helped me. Also the police and rescue squad folks. A cop was
on scene in mere seconds and the ambulance in less that two minutes.
Amazing nothing broken on me. I need a Phantom of the Opera mask for a
few weeks and Advil is my best friend. The bike was not as luckly as
me. Major damage to handelbars, computer, sunglass, helmet, etc.

To the question. How the hell can a $150 pare of so call high
technology pedals with chrom-molly axels just shear off right at the
crank? These guys are just less than a year old. Have nearly 5,000
miles on them. They were attached to my Lemond Maillot Jaune. Not any
more. Ain't going to trust life and limb to those pedals any more.
Does anyone know if there is any history here? What would make this
happen?

C'mon, Jim. How's about some of that downhome metallurgy to bring
closure to this guy's pain?

My apologies to the OP for using his pain as an opportunity to poke
JB.

D'ohBoy

On Mon, 28 Apr 2008 10:43:58 -0700 (PDT), HazeRider
wrote:

To the question. How the hell can a $150 pare of so call high
technology pedals with chrom-molly axels just shear off right at the
crank?

A pedal spindle is just a screw; the usual way to shear the head off
of screw is excessive tightening torque

Who put the pedals on? If you did it yourself, don't hold out any hope
of getting compensation

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary
** Posted from http://www.teranews.com **

On Apr 28, 10:43*am, HazeRider wrote:
I discovered the hard way yesterday that I should be concerned about
possibility that the pedals on my bike might shear right off in the
middle of a ride. While crossing a major intersection and standing on
the pedals to accelerate after being at a complete stop the right
pedal of my Look Keo Sprints sheared straight off just as I passed the
traffic throwning me face first into the asphalt. It happened so fast
I never perceived the going down portion of this. One second I'm up
and a nano second latter my head and face do a seven-beat stacatto
drum riff on the asphalt. Major thanks to the lady that stopped in her
car and helped me. Also the police and rescue squad folks. A cop was
on scene in mere seconds and the ambulance in less that two minutes.
Amazing nothing broken on me. I need a Phantom of the Opera mask for a
few weeks and Advil is my best friend. The bike was not as luckly as
me. Major damage to handelbars, computer, sunglass, helmet, etc.

To the question. How the hell can a $150 pare of so call high
technology pedals with chrom-molly axels just shear off right at the
crank? These guys are just less than a year old. Have nearly 5,000
miles on them. They were attached to my Lemond Maillot Jaune. Not any
more. Ain't going to trust life and limb to those pedals any more.
Does anyone know if there is any history here? What would make this
happen?

Post a picture showing the fracture site. Pedal spindles can break for
a number of reasons. I broke a Look CroMo spindle in a pre-Keo pedal
probably due to fatigue along with some forging problem. Was your's
Ti or CroMo? -- Jay Beattie.

"Kinky Cowboy" wrote: (clip) A pedal spindle is just a screw; the usual
way to shear the head off
of screw is excessive tightening torque (clip)
^^^^^^^^^^^^^^^^^
Excessive tightening torque certainly can shear the head off of a bolt.
This can happen if a very strong, ham-fisted person uses a "cheater" on a
wrench, It can also happen on small screws, where a normal sized wrench is
capable of producing excessive torque. It is VERY unlikely on a pedal,
where the spindle is not small, and the wrenches that will fit into the
available space are never really large.

You are suggesting that the failure was initiated by overtightening, which
resulted in fatigue failure 5000 miles later. A properly heat-treated
spindle should not fail in this way. It should be impossible to initiate a
stress crack with a pedal wrench.

On Apr 28, 2:37*pm, "Leo Lichtman"
wrote:
"Kinky Cowboy" wrote: *(clip) * A pedal spindle is just a screw; the usual

way to shear the head off of screw is excessive tightening torque (clip)

^^^^^^^^^^^^^^^^^
Excessive tightening torque certainly can shear the head off of a bolt.

Assuming a steel spindle and aluminum crank threads, wouldn't you
strip the crank before achieving enough torque to pop the "bolt head"
of the spindle?

Martin Borsje wrote:

I'd should say: do not in any case accept this!

This may not have happened!

I don't know exactly how this works in the US, but I suggest to hold
your LBS, where you bought it, responsible for all the damage to you
and your bike.

Do this by registered writing accompanied by a witness statement as
from the police officers present and pictures of the pedal/axle.

I agree with first replier's suggestion *not* to send the pedal
itself.

If I were to try to reconstruct the cause of failure, I would like to
see the pedal and the spindle to determine if it is a fatigue failure
(spindle is in straight alignment when fit together) or whether it
sustained an earlier bend that initiated failure. Also the fracture
face would probably reveal how long the crack was in development.

Only accept inspection by certified third party experts.

It might help to have a friend/colleague with knowledge about metal
failure mechanisms who can inspect and write a short report,
attached to your letter.

The fracture face will probably reveal the most information although
impact gouges on the pedal exterior would also reveal whether the
spindle had previously received an overload.

Can you publish some pic's of the fracture?

Success and pls keep us informed about proceedings!

Jobst Brandt

a shy person wrote:

To the question. How the hell can a $150 pare of so call high
technology pedals with chrom-molly axels just shear off right at
the crank?

Ice skating not allowed here! No Axels! Did you mean chrome-moly
aka 4130 steel.

A pedal spindle is just a screw; the usual way to shear the head off
of screw is excessive tightening torque

....while tightening.

Who put the pedals on? If you did it yourself, don't hold out any
hope of getting compensation

If the pedal didn't break when it was "over tightened" it was not
affected by tightening torque in an aluminum crank. From experience
we know that pedals are never too tight to move in the crank in use,
be that an aluminum or steel crank. The face of the crank shows
erosion from continual movement, the reason for left pedals to have
left hand threads.

Jobst Brandt