Mitigating crank failure

Phil said:

With another customer's broken crank coming in this week for replacement,
I've been thinking... is there a better solution to all these broken cranks?

Seems like avoiding contact altogether would be preferable, by moving
the feet farther out... longer spindles or an extension of some kind.

Some cranks are better than others, too. What sort of cranks are you
seeing this on?

Moving feet out - i.e. increasing Q factor - is a bad idea.

If you want to avoid shoe rub, why alter shoes at all? For those people
with multiple shoes, that's a lot of money to replace them all. Plus,
anything like felt is absorbent, and would just suck up the
mud/dirt/rain/muck and become a nice abrasive pad.

If you really are concerned about it, get one of those Lizard Skin
chainstay protectors, cut it in half, and put one half on each
crankarm. Cheap, easily replaceable, works with any shoe. If you made
these commercially you could just sell neoprene tubing of an
appropriate size - you don't need the velcro attachment like the Lizard
Skins have, since you can just take off the pedals and slide a bit of
tubing over the crank end.

Phil said:

With another customer's broken crank coming in this week for replacement,
I've been thinking... is there a better solution to all these broken cranks?

What manufacture are these cranks?

Quoted message said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub. Since nobody would pay for cranks with a "shoe rub shim" on
it, why not sell shoes that have felt/terrycloth/foam bits that cover the
inside of the ankle? This would be unobtrusive, could be dyed the color of
the shoe, and cut down on deeper cuts in the metal that would start cracks.

These shoes could be sold to the radonneur/brevet/messenger/commuter/old
fart group of riders that would appreciate such a feature.

Thoughts?
--
Phil, Squid-in-Training

Phil said:

With another customer's broken crank coming in this week for replacement,
I've been thinking... is there a better solution to all these broken cranks?

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub. Since nobody would pay for cranks with a "shoe rub shim" on
it, why not sell shoes that have felt/terrycloth/foam bits that cover the
inside of the ankle? This would be unobtrusive, could be dyed the color of
the shoe, and cut down on deeper cuts in the metal that would start cracks.

These shoes could be sold to the radonneur/brevet/messenger/commuter/old
fart group of riders that would appreciate such a feature.

Thoughts?

If you are really into "high performaqnce components", I would suggest
that you remove the cranks and have them coated with synthetic diamond
or "diamond-like carbon" to increase wear resistance.

There are other hard wear resistant coatings that could be applied for
the lower cost or second quality level biking components.

--
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
3) Don't Diet Without Supplimental Nutrients... Chapter 23 title, Atkins
book
4) A sensible eating plan, and follow it. (Atkins, Self Made or Other)

Per Phil, Squid-in-Training:

Quoted message said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub.

How about a layer of clear packing tape over the area?
--
PeteCresswell

Phil said:

With another customer's broken crank coming in this week for replacement,
I've been thinking... is there a better solution to all these broken cranks?

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub. Since nobody would pay for cranks with a "shoe rub shim" on
it, why not sell shoes that have felt/terrycloth/foam bits that cover the
inside of the ankle? This would be unobtrusive, could be dyed the color of
the shoe, and cut down on deeper cuts in the metal that would start cracks.

These shoes could be sold to the radonneur/brevet/messenger/commuter/old
fart group of riders that would appreciate such a feature.

Thoughts?

Adding thickness to either side (shoe or crank) will just make shoe rub
more annoying. The only solution I'd consider is an increase in the
spacing. But many don't like a wider Q factor, so I guess we'd be stuck
with the lowest profile cranks available. Maybe the angle of the arm
could be adjusted, too.

--
Dave
dvt at psu dot edu

Phil said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub.

Is it?

http://pardo.net/pardo/bike/pic/fail/crank-fail-002.jpg

http://www.atmosp.physics.utoronto.ca/people/amit/crank.htm

http://pardo.net/bike/pic/fail-001/CrankmodXthree.jpg

http://www.yellowjersey.org/jayscranks.html

http://www.yellowjersey.org/photosfromthepast/yesdeydo.jpg

http://pardo.net/pardo/bike/pic/fail/FAIL-001.html

Quoted message said:

Phil said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub.

Quoted message said:

Is it?

http://pardo.net/pardo/bike/pic/fail/crank-fail-002.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://www.atmosp.physics.utoronto.ca/people/amit/crank.htm

midsection, in region of shoe rub

Quoted message said:

http://pardo.net/bike/pic/fail-001/CrankmodXthree.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://www.yellowjersey.org/jayscranks.html

midsection, in region of shoe rub

Quoted message said:

http://www.yellowjersey.org/photosfromthepast/yesdeydo.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://pardo.net/pardo/bike/pic/fail/FAIL-001.html

pedal eye failure (not at midsection)

None of these photos contradict Phil's assertion. And of course they
don't confirm his assertion, since only one contradictory example needs
to be shown.

--
Dave
dvt at psu dot edu

dvt said:

Quoted message said:

Phil said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub.

Quoted message said:

Is it?

http://pardo.net/pardo/bike/pic/fail/crank-fail-002.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://www.atmosp.physics.utoronto.ca/people/amit/crank.htm

midsection, in region of shoe rub

Quoted message said:

http://pardo.net/bike/pic/fail-001/CrankmodXthree.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://www.yellowjersey.org/jayscranks.html

midsection, in region of shoe rub

Quoted message said:

http://www.yellowjersey.org/photosfromthepast/yesdeydo.jpg

pedal eye failure (not at midsection)

Quoted message said:

http://pardo.net/pardo/bike/pic/fail/FAIL-001.html

pedal eye failure (not at midsection)

None of these photos contradict Phil's assertion. And of course they
don't confirm his assertion, since only one contradictory example needs
to be shown.

--
Dave
dvt at psu dot edu

Phil Squid used the term "invariably". The online dictionary says
invariably means "Not changing or subject to change; constant". From
the pictures above you can easily deduce that shoe rubbing is not a
constant/invariable beginning of crankset cracking. I think a reading
of the FAQ and Brandt's postings about crankset cracking would provide
a better cause and understanding than shoe rubbing. These pictures are
the ones found posted on this forum. I am sure there are other
pictures on the web showing all manner of crankset failure.

Russell Seaton said:

Phil Lee used the term "invariably". The online dictionary says
invariably means "Not changing or subject to change; constant".
From the pictures above you can easily deduce that shoe rubbing is
not a constant/invariable beginning of cranks cracking. I think a
reading of the FAQ and Brandt's postings about cranks cracking would
provide a better cause and understanding than shoe rubbing. These
pictures are the ones found posted on this forum. I am sure there
are other pictures on the web showing all manner of crank failures.

There are more at:

http://pardo.net/bike/pic/fail-001/

Jobst Brandt

In article <R0jcf.1635$Xj5.831@dukeread02>,
[email hidden] says...

Quoted message said:

With another customer's broken crank coming in this week for replacement,
I've been thinking... is there a better solution to all these broken cranks?

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub. Since nobody would pay for cranks with a "shoe rub shim" on
it, why not sell shoes that have felt/terrycloth/foam bits that cover the
inside of the ankle? This would be unobtrusive, could be dyed the color of
the shoe, and cut down on deeper cuts in the metal that would start cracks.

These shoes could be sold to the radonneur/brevet/messenger/commuter/old
fart group of riders that would appreciate such a feature.

Thoughts?

Set the cleats up so that there is no rub. Unless my pedalling style gets
really sloppy, trying to hard when I am tired, my shoes don't touch the cranks.
--------------
Alex

Quoted message said:

Phil said:

Crack propagation on cranks breaking at midsection is invariably started
with shoe rub.

Is it?

http://pardo.net/pardo/bike/pic/fail/crank-fail-002.jpg

http://www.atmosp.physics.utoronto.ca/people/amit/crank.htm

http://pardo.net/bike/pic/fail-001/CrankmodXthree.jpg

http://www.yellowjersey.org/jayscranks.html

http://www.yellowjersey.org/photosfromthepast/yesdeydo.jpg

http://pardo.net/pardo/bike/pic/fail/FAIL-001.html

re:http://www.yellowjersey.org/jayscranks.html

I'm surprised at how little hollow there is in the "Hollow Tech". That
crank is 10% hollow and 90% crank. Hardly worth the effort, or expense.

Is this typical?

John

john said:

I'm surprised at how little hollow there is in the "Hollow Tech". That
crank is 10% hollow and 90% crank. Hardly worth the effort, or expense.

Is this typical?

I think just at that location of the arm it essentally solid. It is
much more hollow in the middle.

Quoted message said:

Moving feet out - i.e. increasing Q factor - is a bad idea.

Possibly so, but if the rider's ankles are contacting the crank arm
their legs are actually quite close together... so they could probably
stand to move them out a bit.

The other thought I had was simply poor cleat setup... or are there
some pedals that have huge float and don't restrict inward heel
movement at all? If so, that would be the solution... the cleats need
to be set up so that ankle rub doesn't happen... and if the rider likes
to have their toes pointed out a lot, then pedal axle extensions make
sense.

dvt said:

Adding thickness to either side (shoe or crank) will just make shoe rub
more annoying. The only solution I'd consider is an increase in the
spacing. But many don't like a wider Q factor, so I guess we'd be stuck
with the lowest profile cranks available. Maybe the angle of the arm
could be adjusted, too.

The shape of different crankarms will make a difference in shoe
contacting the crank. Placement of the cleat in the shoe and type of
shoe can change distance between shoe and crankarm. Type of pedal
makes a difference. Shimano MTB pedals position the shoe a bit
further from the crankarm than road pedals. Washers between pedal and
crankarm move shoe away from arm. Wider Q doesn't necessarily put
shoe or ankle away from arm. Plastic laminating tape on the crankarm
protects it.

I've got big feet and don't like my cranks getting cosmetically
marked. I haven't had a crankarm fail because of rub...yet.

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Russell Seaton said:

Phil Lee used the term "invariably". The online dictionary

says

Quoted message said:

Quoted message said:

invariably means "Not changing or subject to change;

constant".

Quoted message said:

Quoted message said:

From the pictures above you can easily deduce that shoe

rubbing is

Quoted message said:

Quoted message said:

not a constant/invariable beginning of cranks cracking. I

think a

Quoted message said:

Quoted message said:

reading of the FAQ and Brandt's postings about cranks

cracking would

Quoted message said:

Quoted message said:

provide a better cause and understanding than shoe rubbing.

These

Quoted message said:

Quoted message said:

pictures are the ones found posted on this forum. I am sure

there

Quoted message said:

Quoted message said:

are other pictures on the web showing all manner of crank

failures.

Quoted message said:

There are more at:

http://pardo.net/bike/pic/fail-001/

So, is shoe rub (which causes polishing rather than scratches)
capable of causing or accelerating crank failure? -- Jay Beattie.

Quoted message said:

dvt said:

Quoted message said:

Phil, Squid-in-Training wrote:

>Crack propagation on cranks breaking at midsection is invariably started
>with shoe rub.

Quoted message said:

Phil Squid used the term "invariably". The online dictionary says
invariably means "Not changing or subject to change; constant". From
the pictures above you can easily deduce that shoe rubbing is not a
constant/invariable beginning of crankset cracking. I think a reading

No, you really can't. On all the cranks *breaking at the midsection* you
found, visible shoe rubbing was present around the crack.

Jasper

after the last crank failure i rotored over to the LBS and asked for
the crank box
paleontology-worth the study-crank design!!!
picked out 4 and threw em in the bottom of toolbox 3
now i pray the CR stays
also see Crank saver in archives

jbuch said:

Phil said:

With another customer's broken crank coming in this week for
replacement, I've been thinking... is there a better solution to all
these broken cranks?

Crack propagation on cranks breaking at midsection is invariably
started with shoe rub. Since nobody would pay for cranks with a "shoe
rub shim" on it, why not sell shoes that have felt/terrycloth/foam
bits that cover the inside of the ankle? This would be unobtrusive,
could be dyed the color of the shoe, and cut down on deeper cuts in
the metal that would start cracks.

These shoes could be sold to the
radonneur/brevet/messenger/commuter/old fart group of riders that
would appreciate such a feature.

Thoughts?

If you are really into "high performaqnce components", I would suggest
that you remove the cranks and have them coated with synthetic diamond
or "diamond-like carbon" to increase wear resistance.

There are other hard wear resistant coatings that could be applied for
the lower cost or second quality level biking components.

you'd better not mention wear resistant anodizing on this group....