Sudden and Catastrophic Carbon Fork Failure

[Maxpilot]

I am surprised that Cannondale left the bladders inside the fork legs. I guess they are hard to remove after the CF fork is cured. Another surprising thing is how one of the fork legs broke in almost a straight line across the width. It looks almost like a cut or hairline fracture. The other fork leg is ragged and has 45 degree shear that would be expected in a sudden failure. I am also surprised that both fork legs snapped at the exact same area along the length of the fork leg. It shows an equal amount of force applied to each fork leg at the same time. The wheel took a force straight on to cause the force to be transmitted to each leg equally. There was no twisting indicating that both legs snapped at the same time. OP - Can we see the front wheel?

 

[vspa]

i hope that this is not some kind of "joke" picture setup... the other day i was thinking about this fork while going downhill at speed, i was thinking how easy you could get serious injury with such a failure,

 

[531Aussie]

Originally Posted by alienator .


How about an aluminum fork with a CF steerer? You could be the first kid on your antipodean block to have one.

Hmm, well, I do like being different.

By the way, I'm still using your "Tour Magazine proved that the steerer flexes inside the steerer" quote to impress people. It's true, right?

 

[alienator]

Hmm, well, I do like being different. By the way, I'm still using your "Tour Magazine proved that the steerer flexes inside the steerer" quote to impress people.  It's true, right?

It's absolutely true. It's all about the bending modes that exist when a fork steerer is supported by two bearings and a load is applied by the wheel, at the end of the fork.

 

[531Aussie]

bewdy!

 

[ChrisRider]

wow thats pretty full on, those photos show a clean snap, on both forks at the same spot. Im always a bit wary of carbon forks myself.

 

[6fhscjess]

I had the Reynolds Ouzo Pro on my bike for ten years and liked it very much. The ride was smooth and sure. I now have the Easton EC90SL and feel the ride is just as good. I did not want to risk it with the SLX.

 

[CAMPYBOB]

"I did not want to risk it with the SLX."

The EC90SLX is a very thin-walled fork. I'm not a heavy rider and the fork has a lot of flex to it. The carbon steerer AND the blades both move a lot under stress.

 

[Limbatus]

Can you have a carbon frame or fork examined for internal fatiuge? I know a metalurgist, that analyzes metal parts for the airlines. Is there a similar process for inspecting carbon? are you putting yourself at risk by riding carbon more than say 5 years?

 

[alienator]

Can you have a carbon frame or fork examined for internal fatiuge? I know a metalurgist, that analyzes metal parts for the airlines. Is there a similar process for inspecting carbon? are you putting yourself at risk by riding carbon more than say 5 years?  

If you've taken care of your bike and haven't crashed, it's likely you're taking no risk in riding it. However, if you've got worries, you can test CF with x-rays and also with ultrasound. If you were in the right place and of the right mind, you could check the CF with a sound generator and speckle holography. That's what was used in my lab to test prototype CF turbine blades. Of course doing so required painting the turbine blades with titanium oxide.

 

[Markjyost]

This happened to me three days ago.

I thought the quick release must have been loose and the wheel just popped loose when I hit a bump. I'd never heard of "sudden and catastrophic fork failure."

My face served as the brakes and I ended up in the ER.

How often has this happened? My Litespeed Icon was five years old and has never been abused. No crashes.

And I wasn't going fast (13-15 mph max), but if it happens during a fast descent, it'd all be over but the memorial service.

 

[alienator]

This happened to me three days ago. I thought the quick release must have been loose and the wheel just popped loose when I hit a bump.  I'd never heard of "sudden and catastrophic fork failure." My face served as the brakes and I ended up in the ER. How often has this happened?  My Litespeed Icon was five years old and has never been abused.  No crashes.

Your picture doesn't show much so it's hard to get a feeling for what happened. How about a picture of the whole fork? Fork failures aren't very frequent at all these days.

 

[CAMPYBOB]

Did Mathew Brady take that picture for you?

Yes, there is definitely a well documented "Sudden and Catastrophic Fork Failure Syndrome". The Busted Carbon website has a few multi-piece forks on display.

Best of luck with healing your face graft and/or dental implants. Fork failures are one of the things in life worthy of the best personal injury lawyer in your state. There is no excuse for an otherwise un-abused fork to face plant a rider into planet earth.

 

[Markjyost]

It's a bad cell phone picture too. I'll get the rest of the bike back from the police tomorrow and take a better picture, showing both sides of both breaks.

The bottoms of the forks, where the wheels were, show no damage at all. I originally thought it must be quick release failure, but it seems that if that were the case, the bottoms would be pretty beat up from high energy contact with the street.

Thanks God I wasn't descending in the mountains, like I do regularly.

 

[Markjyost]

Thanks for the link. The bad picture is all mine, from a cell phone. Can't blame anyone, certainly not Litespeed for that.

 

[CAMPYBOB]

Not so long ago...bicycles used to be relatively safely made machines and catastrophic frame and fork failures were much less commonplace than the failures of the carbon revolution.

Way back in the dark ages of cycling...the 1970's to be specific...there appeared upon the landscape a new, lightweight bicycle manufactured by Lambert (later, Viscount) that featured a cast aluminum fork pinned (or not) to a steel steerer tube. This was done as a sacrifice to the Godz of weight.

These forks failed. The failures resulted in serious injuries and disfiguration. Also known to fail on these piece of **** bikes were the bottom bracket spindles at the circlip cut/groove.

The forks were almost immediately called "Death Forks" and still are referred as such to this very day. Eventually, Yamaha purchased the Lambert/Viscount brand and recalled every damned Death Fork manufactured and replaced it with a free steel Tange fork. They also paid for bike owners to have the fork installed.

Why? Because one good lawyer could exceed the total recall cost with just one killer lawsuit.

Today, folks are much too accepting of the dangers associated with a frame or fork failure. The same goes for pedal spindles and crankset assemblies IMO.

Insured or not, offer of another free fork or not...get an attorney and recover every dime of expense caused by this failure.

 

[oldbobcat]

Originally Posted by arnehuse


I am not speculating that a small battery could have taken out my forks like that, it's just the only thing that was in the area afterwards.

I'm glad Cannondale is replacing your bike and that you didn't become a wrongful death product liability risk to them.

I'm curious about the bike though. I've seen photos of this kind of failure before, but never in person. That battery would have had to be moving pretty fast to hit anything hard enough cause an impact failure. Could a wheel reflector in the spokes possibly have become unmoored? Also, it looks like some sort of inflatable bladder was used in the molding process and left inside. Very interesting.

 

[CAMPYBOB]

"Also, it looks like some sort of inflatable bladder was used in the molding process and left inside."

It is. They are used to compress the resin and CF against the mold walls to control wall thickness and minimize voids. The bladders are almost always left in place due to difficulty of removal from monocoque structures.

 

[CAMPYBOB]

Bladder being inserted prior to autoclave op:

 

[oldbobcat]

Originally Posted by CAMPYBOB
Bladder being inserted prior to autoclave op:

I've seen wax molds, and fragments of bladder inside my Giant TCR.