Epic carbon fork fail.!

Out on a road ride today and heard a crack behind me followed by “man down”. I turned round to find a twisted mess of man and bike and this… 😯

Fortunately the forks were the only thing broken but there was a lot of skin missing.

send the pictures here[/url]

Nasty

could i have the broken bits,i’m making a wheel jig

could i have the broken bits,i’m making a wheel jig

Not mine I’m afraid but I can ask.

could i have the broken bits,i’m making a wheel jig

I’d imagine Scott and/or the shop that he bought the bike from might want to see them…

So what did he do / hit? How did it happen?

Nasty. Really just went for no reason? But yes get them back, surely if one sets gone for no reason then others could.

Looks like one of Cynical Al’s jobs 🙂

Pothole seems the most likely candidate, not a big one mind probably 8-9 inches in diameter and 4-5 inches deep. There was a half a dozen spokes broken as well but we couldn’t decide on the order of events.

All frame materials fail but only carbon fails like this. Buying from a reputable brand does not protect you either as in this case. Glad the rider was mostly ok.

wow, ouch, wow

Aluminium forks fail similarly …….

Steel fotks mostly bent .

Fwiw ive seen seven carbon forks driven into a low bridge on a car roof turn the ti frame into scrap without failing !

Was he riding with eyes closed or was there no group etiquette towards potholes if in a group – 8-9 inches and 5 inches deep is a cavern ……

Wish him a speedy recovery though !

In my experience of a similar accident, steel forks bend and destroy the steel frame too.

I hit a similar pothole yesterday. Cornering and being overtaken by a car, I had little chance to avoid it. There was a loud crack and Immediately shat myself but all that seems to have happened is that my bars have rotated in the stem by15 degrees or so (Easton EC70 forks).

The only pics I’ve ever seen on failed steel or alloy frames are either bends or stress fractures. we’ve all seen endless examples of this catastrophic carbon failure. Who cares about warranties, this stuff permanently disables people.

not a big one mind probably 8-9 inches in diameter and 4-5 inches deep.

What exactly would you define as big? Because If I hit that at speed I’d expect me or the bike or both to be broken.

Ive noticed that you get a lot of mileage out of that pic. I guess it saves from trying to think and intelligently contribute to discussions. I guess we all have our limits and you keep well within yours.

I agree, he should have just called you an asshat.

we need more helpful dissing of entire threads like that from hugor..it is especially good when they hint at superior knowledge but dont share this.
I have never seen aluminium or steel forks fold like that on a pothole

Wasn’t dissing anything.
My issue here is the mode of failure.
Bends and stress fractures give you some chance of saving the situation.
Catastrophic failure gives you no chance.

Hmmm my thoughts….

Aluminium or Steel will usually signal the failure long before it actually fails in a catastrophic manner. There will be cracks, bending, creaking etc… and it will be visible as metals are homogenous structures and a crack will penetrate fully or simply will not exist.

Carbon fibre structures, being layers of carbon fibres in a resin, can hide minor cracks, delamination etc… within the layers. Until it’s too weak to sustain an impact such as this. Then “bang” and a catastrophic failure.

IF you own this stuff you have to be a bit more observant than usual and the original design has to be even more tolerant of abuse.

I hope your mate gets better soon and that this was a design related failure rather than just wear/tear/fatigue.

Agree entirely with above.
But let’s not let a little knowledge get in the way of an argument.

Another thought, after looking at the pictures again….

It seems unlikely that both fork legs would be hiding cracks/delamination in similar places and fail simultaneously.

My suggestion is that the wheel failed first (you mentioned spokes??) and the subsequent loading on the fork caused it to fail.

Let’s hope he heals quickly 🙁

Most pics of failed carbon frames I’ve seen including those in the link above show it failing in 2 places at once.
In this case we have a ring of a fork which is completed by the axle. A rigid ring cannot fail in one place. It has to fail in 2.

My issue here is the mode of failure.

Having seen quite a lot of failed components, ime it makes sod all difference what the material is. a bar bends then snaps. a fork bends then either folds or locks the wheel.

I choose carbon because I feel safer on it.

surprised no one has mention carbon fibres heading for the heart.

It’s very rare for forks to fail in the middle – same as spokes – they always go at either the crown or the dropouts.
The only other pair of carbon forks I’ve seen snapped like that took one hell of an impact in a side on crash which wrote off the front wheel.

Just wondering if he hit the pothole, damaged the wheel, crashed and *that* broke the forks or if the forks failed and caused the crash. My guess is the first scenario.

Whichever, it’s time to ignore the general shite spouted about carbon vs steel vs aluminium, take the bike back to the shop and see what options there are for getting it sorted.

Could have been really nasty. :winces:
My so killed a pair of HSC3 forks when someone ran out into the road infront of her as she was riding at 25mph. Ripped one of the dropouts out and one fork leg broke at the crown – also ground down a pair of Chorus ergos to the brake pivots. she wasn’t very impressed – although she had to wait in A&E for awhile as they were attempting to revive a car crash victim. As she said to the ambulance guy waiting at reception with her “puts things in perspective”.
Hope your mate’s ok.

and it will be visible as metals are homogenous structures and a crack will penetrate fully or simply will not exist.

That’s excellent news, I’ll be able to tell the NDE chaps at work that they don’t need to bother to xray/UT stuff any more 😉

Something went through the wheel, jammed against the forks (stopping rotation) and the forks failed at the contact point?
I know someone who had a nasty accident after a rabbit jumped into their front wheel and brought things to a rapid halt.

i saw enough shattered carbon whilst working at a cannondale test centre to put me off using it.

at least once a week there would be another broken Super6 on the rack. a broken fork, snapped seat or chain stay, a light crack in the top tube where the user lent it against a wall or railing…..

had three guys end up in hospital due to carbon failures (had lots more end up in hospital as a result of rider idiocy).

i lost count of the number of FSA carbon bars that were replaced. when the bars were fitted to the stem using a torque wrench you’d still find that the carbon had de-formed after a month of use.

horrid stuff, IMO.

All frame materials fail but only carbon fails like this

I’ve got a pair of forks in the garage snapped.

They’re steel though, sorry to disappoint your world view.

at least once a week there would be another broken Super6 on the rack. a broken fork, snapped seat or chain stay, a light crack in the top tube where the user lent it against a wall or railing…..

How many carbon frames do cannondale sell in each of those weeks though?

Bends and stress fractures give you some chance of saving the situation.

Depends, maybe if you spotted them, if not your still feked!

could i have the broken bits,i’m making a wheel jig

Got a couple of pairs of busted reynolds 531 forks from over the years, unfortunately there’s not bustedsteel.org website so nowhere to host pics of them. Any use to you? One pairs bent, the other’s got about 2″ of steerer tube left after it snapped.

its all down to human error in the end

I see enough broken carbon working as a cycle mechanic to distrust it. I’ve still got carbon seatposts and suspension fork lowers though.

It’s not all down to human error in the end. It’s down to the fact carbon fails catastrophically and is more prone to hidden damage than other common materials in the first place.

Still the best material for light and strong – at least at the point of manufacture, if made properly.

My Verdict : avoid unless rich and must have the lightest, or sponsored. A manufacturers dream as if they play their cards right the warranty costs shall be offset by the large profits and shorter product lifespans, meaning returning customers.

I find it strange that if Carbon is such an inherently dodgy material that so many of the big manufacturers are pushing forward with it, surely it woudnt be worth their while if they were going to get warranty claims every 5 minutes…… I’m not sure that the shorter product lifespan argument makes much sense. Anyhow, carbon frame, seapost and bars and I’m not dead yet.

I know someone who had a nasty accident after a rabbit jumped into their front wheel and brought things to a rapid halt.

Would you care to elaborate on this?!

YAWN The record is as broken as those forks!

If you guys really want a bike that won’t hurt you when something breaks then you are going to have to ask for one with some redundancy and be prepared to ride a bike that weighs 90% more as all the critical structure (which lets face it is pretty much everything on a bike) has to be doubled up. Regardless of the material every bike part is made for minimum weight for what it does and as such any failure will normally result in total failure of the part.

I find these scare scaremongering views on carbon but no actual real knowledge of it or seemingly metal failures quite ignorant tbh.

Now for some evidence:

All look pretty catastrophic to me and all magical metal which couldn’t possibly have hidden faults 😉 (look up United Airlines Flight 232 )

PS glad your mate is okay. Bike parts can be replaced.

how is it not down to human error Do you think its the carbons fault in fact its pretty useless just sat there on its own,Just like aluminium,Steel,Titanium ,Somewhere along the line someone made an error wether it be design manufacturing or end use ,end of lifecycle .it was a human that brought it into existence it all boils down to that at the end of the armchair engineering analysis things don ‘t just break.

Where the OP’s forks failed0looks like a design flaw to me, unless there was an impact right there.

I can’t imagine a pothole did it, he’d have flatted and trashed the rim.

An impact of this magnitude means you are over the bars no matter what material your forks are.