Broken Colnago Carbon Crank

[MGS9500]

I just posted my Serotta with S and S couplers in the image gallery.

I installed a carbon FSA compact crank without any problems.

To show a previous interesting problem with carbon cranks, these are my cranks off a Colnago bike. They failed while climbing a hill.

I have never seen a crank other than the Colnago fail in this fashion.

[shinomaster]

boy that Ferrari sure can build with carbon!!

[bfd]

shino states:

<boy that Ferrari sure can build with carbon!!>

Where is it stated that Ferrari built Colnago cranks? Trialtir, Colnago's US distributor doesn't say anything:

http://www.trialtir-usa.com/2004-colnago/accessories/components/carbon-cranks.html

[BumbleBeeDave]

. . . in the chainring at the lower left? Or just a scratch?

In any event, was this warrantied?

BBDave

[SPOKE]

does that colnago crank have a foam core?? very interesting indeed. looks like it was done in a clam shell type mold then injected with structural foam. or the foam core is produced then the carbon is laid up around it. not sure but i would have thought the crank arm would have had an aluminum spine similar to the FSA product.
hope the crank was warrantied.

[shinomaster]

i could be wrong as usual...

[Kevin]

mgs,

That is scary. You must generate alot of power.

Kevin

[Too Tall]

Is it only me who is shocked that the carbon does not extent 360 around the arm? Tell me I'm wrong and seeing this oddly but it looks like two halves put together with only a wrap or two of carbon??? BOGUS.

[Bill Bove]

A buddy of mine just got a new pair of Colnago cranks, his old ones were recalled. Check with the guy you bought them from, you should at least get a new set, if not get a lawyer.:argue:

[Redturbo]

I had a set of Cdale/Coda AL cranks that were 2 piece split on one of my Mt bikes a few years back. It was not nearly as dramatic/catastrophic as these.

turbo

[zap]

Certainly looks like a bad design. Two halves with a cosmetic wrap. It appears that the pedal insert failed on one half and all the stress was transfered to the outer portion causing the failure. Check with the importer and see if you can get a replacement and find out if the newer cranks have been redesigned. Keep us posted.

Storck carbon cranks from Germany had a similiar problem with pedal inserts failing and redesigned the crank 2 -3 years ago and appear to work well now.

FSA took the conservative route and used an aluminium spline to transfer a portion of the load from the pedal insert to the BB spline. The newer Superlight model uses a carbon spline.

[Jeff N.]

I don't have any pictures but you should've seen what happened to my ZIPP carbon crankset! The pedals stripped right out of the arms! Biggest piece of garbage I've ever seen. Looks like your Colnago crankset belongs in the same pile as Zipps! Jeff N.

[Ozz]

One word: "plastics"

The price of progress!

Sorry about your crank - hopefully no injuries were involved.

[vaxn8r]

I think it's more complicated than to just say 'plastic". We (almost) all use plastic forks every day and I've used a plastic frame for 7 years (and I weigh 190).

What I think is that the engineering has to be correct and I bet CF cranks are on the steep part of the learning curve. I also think some builders understand and do plastic better than others.

[vaxn8r]

I've mentioned this before and I'm sure I'll mention it again....I've seen a Record aluminum crank fail catastrophically on the mid shaft. I don't have any idea how often this occurs but there are no guarantees with any of our equipment.

[vaxn8r]

I've mentioned this before and I'm sure I'll mention it again....I've seen a Record aluminum crank fail catastrophically on the mid shaft. I don't have any idea how often this occurs but there are no guarantees with any of our equipment.

[bfd]

crank or bb breakage isn't limited to Campy, for example:

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

campy:
http://www.campyonly.com/mypages/retrobike.html

FSA:
http://sheldonbrown.com/fsabb.html

and of course, the "famous" wheelsmith collection:

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

as Ric Hjertberg states:

"Campag cranks were the vast majority of failures because they saw the really serious miles. Victims were sure not to stray from Campag for fear of even worse experiences. The more of their cranks you broke the more you recommended to others like yourself to use nothing else."

[Ozz]

:) :D :) :D :banana: :banana: :banana:

vaxn8r,

Sorry I omitted these from my previous post which would indicate my (feeble?) attempt at humor.

I realize a well designed crank (or any part) will perform better and be safer than a poorly designed one.

I would say however that the material used should make us wary of the margin for error.

I could probably design a safe and functional, but very heavy, crank out of steel.

Aluminum would be next to impossible. I wouldn't want to use it.

Carbon? I would not even know where to start....:crap:

BTW - I have a "plastic fork" (F2) and trust it implicitly cuz I trust the builder! However, I am still tempted to try and get a steel fork with 1.125" steerer built for my bike.

:cool:

[MGS9500]

I sent the cranks back to the shop that sold them. They took them to trialtir which apparently told them they had never seen a failure like this.

I was given the option of a new Colnago crank with a "new design", or a full refund. They did not explain why a "new design" was necessary if there was no problem being reported with the cranks.

Needless to say, having had a catastrophic failure, I opted to exchange them for Campy Carbon, which were at the time, equally priced.

I have never heard of a Campy Carbon failure.

The cranks do look like they are a "clamshell" design around a foam core, with superficial layering to bond the clamshell together.

All in all, not a great design. One wonders how a bike maker like Colnago would accept such a design, knowing their experience with carbon monocoque frames.

The caveat here is probably stick to cranks made by component manufacturers, and not by frame makers who puchase other brands and put their sticker on them.

A little more information on the story, the cranks failed going up a rather small hill, about 6% incline. I was out of the saddle, but not putting excessive force on the pedals. There was no warning, creak, or any sign of failure. I check my bike out before all rides, tires, chain, quick release, etc.... and saw nothing out of the ordinary.

The failure occured about 20 miles into a 40 mile ride.

I was on my own, and after the failure occured, I wondered how to get home. My wife was out for the day and no name came to mind as to how to get help.

A friendly police officer stopped and took my bike and me the 20 miles to my house.

I got his name and badge and wrote a letter to his chief relating the kindness.

[Chief]

Hey MGS9500,

My speciality is fracture mechanics and I try to collect good pics of catastrophic failures. Would you be so kind as to send me the file of your neat pic as an attachment in an email message to cpopelar@msn.com.

Thanks.

[TmcDet]

you can right click on the picture and save it on your computer

[SPOKE]

i had to replace the left crank arm on my serotta 30th anniversary bike. it was the first generation campy crank. the aluminum insert bonded into the crank arm for attachment to the BB spindle managed to come loose. didn't completely fail but the noise was very bad and in the 4 miles i had to ride back it was only getting worse. campy replaced the crank arm no questions asked.

[Too Tall]

VAXN8R your point is that we need to accept some amt. of product defects as part of the owner process? Hope I'm understanding you right. Respectfully disagree. I'd think if Colonago had better quality control that would not have happened.

[Climb01742]

there is no excuse for poor quality control. but perhaps sometimes we adopt new products too quickly, before they have been (unfortunately) debugged in the real world. or we accept some degree of product risk for a precieved benefit. case in point: low profile rims on a car. better performance, yes. sucky for new england potholes. but to the larger point being discussed, if a manufacturer has made design compromises (or trade-offs) to achieve a desired attribute (say, shaving weight but sacrificing strength) then be upfront with consumers. let riders know the trade-off, understand the risks, then make an informed buying decision. wrapping something in carbon seems deceptive at best, and dangerous at worst.

[zap]

It's hard when your crank breaks in the middle off a ride. My wife and I were riding our tandem when the pedal threads stripped on my left Mavic crank. Who to call!!!

It was a moderatly hilly ride back to our car but my wife pedaled pretty darn hard and my right leg got one hell of a workout. It's also amazing how sore the butt gets when you lose the support of one leg.

By the way, I got the crank helicoiled and it's still holding up after several years of use. Can't do that with carbon.

Someone mentioned that Ferrari designs and fabricates Colnago carbon bits. There does appear to be a lot of colaboration between the companies but it would be interesting to find out exactley what the relationship is. Also, does Colnago build anything or is it all contracted to others?

[vaxn8r]

Too Tall,

I'm not sure I follow your logic. Do you think there is never an excuse for equipment failure?

While I do agree that, especially with carbon fiber, products are rushed to the market before proper testing. But you simply cannot test every possible manner in which a product may fail. In my field, drugs are approved by the FDA after thousands of animals, then even more thousands of people are extensively tested and observed for several years. You know what? Sometimes a product is released and there are still deaths and significant side effects that didn't show in the relatively smaller study sizes. Why should bicycle components or frames be any different? I would expect more failures in cycling frames and components because there is no "FDA" of bicycles...or would that be FBA? Anyway, my point is, even if Colnago's crank were tested by 20,000 riders over a 7 year period (not practical) we still might see some failures once millions were in service.

I ride knowing that risk. But I've seen failures on stems, bars, seatposts, frames, wheels. Every failure has been from an established, respected company. Maybe we ought to have a centralized frame and component testing facility but I doubt for monetary and political reasons that will ever happen.

Sorry if I didn't get the point you were trying to make.

[Too Tall]

Maybe I didn't have a point, would not be the first time. Yes, me too. I've seen plenty of failures in otherwise reliable products. heck, I broke a new Look pedal axel after 300 miles. But you have to wonder why I continued to ride campy nuvo record cranks even after breaking 3.

Maybe I'm a little bent that Colonago had the chutzpah to charge that kind of freight for a shabby execution?