CPFITNESS

as a golf club builder I can tell you carbon fiber/graphite is quite strong. I've broken graphite shafts and I've seen steel shafts break too (generally steel breaks when someone doesn't play golf often, gets some water inside their clubs somehow and they sit and the shafts rust from the inside out then you swing and KAPOW, off with the head!)

When a graphite shaft breaks it's usually just above the hosel (that is the neck of the clubhead if you will) typically it will break there if the tip of the shaft was improperly prepared or if there wasn't enough of a parallel tip on the shaft and it was inserted too deep into the hosel so it can't flex properly. you will NEVER see a graphite shaft break halfway up the shaft. If that happens you can rest assured it's because someone threw the club into a tree or snapped it over their leg. Graphite breaks more often mainly because it may get damaged just sitting in a bag if you dont' have headcovers on. I don't think of my headcovers as protecting my clubheads, I use them to keep my iron heads from wacking into my graphite shafts as i walk/ride the fwys.

The moral of the story is that I know jack **** about bikes, but I know that carbon fiber is VERY strong and will generally only break if some easily detectable damage has been done to it or if it is abused. there is no need for us to fear riding a bike with a carbon fork. It sucks that the OP's frame got completely trashed but hopefully he can strip his parts and throw them on a cheap frame in he short term.

Grumpy McTrumpy

polyurethane =/= rubber


look it up.

motorthings

glad the op is doing well, but i also have a story for all the "now i am skittish/worried about carbon forks and/or are getting a steel fork asap" responses.

this is an odds on "freak accident", and to respond to it with that kind of teeth gnashing and rending of garments reminds me of a story i heard from a co-worker. when he was a child, he and many of his other friends were at the local pool. another kid came whizzing down a big hill that led up to the pool on his bike when he crashed in front of everyone and somehow ended up with the his bike's kickstand in his eye socket. it was gory, and he lost the eye, and that week, most of the parents took the kickstands off their kid's bicycles.

see what i mean?

AEO

hmm?
https://en.wikipedia.org/wiki/Elastomer
https://en.wikipedia.org/wiki/Thermoplastic_elastomer

gbg

The first was from Gent–Wevelgem , I think this was when he was sprinting in a race and at full sprint ran into a 2' high concrete obstruction.
The second was female rider Liz hatch approached a corner full of pine needles at more speed than was actually safe. She rode right into the guardrail at 45K.

In other pictures the frames look fine, steel or aluminium would not fare that well.

Fleabiscuit

I'm not buying the story about this fork spontaneously breaking in the exact same spot on both legs, cleanly, without hitting anything, causing the wheel to hit the downtube and buckle it. It looks to me like the OP hit a pothole, crack in the road or a small curb, some kind of impact caused the fork to fail.

If CF forks were this brittle, we'd see tons of these types of malfunctions. The OP is not a small guy but he's certainly not a clyde (maybe borderline technically but he's no 250lb horse on the bike) and riding down the street and applying light brake pressure is not going to cause a fork to cleanly break like his did. Also, the odds of his rim contacting his downtube, denting the rim and buckling the downtube are pretty slim. We're making this way more complicated than necessary and I'll give the guy the benefit of the doubt because he hit his head pretty hard and probably doesn't remember the details fully. I've had lots of MTB crashes, some at high speed and it's very hard to remember the events once you are flying over the bars.

Either way, the is only one way to really know for sure what really happened...

Ryleeryno

Be sure the send in that helmet for a discount replacement. Bell and Giro like to analyze crashed helmets.

X-LinkedRider

Love that show. Even though they clearly leave out so many variables that their results are nonsense occasionally. Jamie and Adam could solve it, or at least make it as entertaining as we want it to be.

embankmentlb

Is it possible the op damaged the fork minutes or moments before the actual failure? Anyone borrow the bike before this last ride? It looks to me life this break was done before the final crash & not noticed by the op.

akansaskid

I t-boned a car at about 15 mph with a 30-year old steel frame/steel fork Motobecane last year. Partially straightened the curved fork; bent the top tube and the down tube about four inches behind the head tube. Front wheel was pushed back past the down tube and wedged itself there. The wheel was totally undamaged. The rim damage I see on the OP's bike looks like it hit an edge rather than a blunt, flat surface. Possibly a pothole or pavement crack, but not a curb or low wall. But I'd think the tire would have pinch-flatted in such a case.

Moreover, there's little flex possible in a carbon fork; it will shear before bending enough for the tire to contact the down tube. Once the fork snapped, all abnormal forces were relieved from the down tube. I suspect the fork snapped and the down tube bent about the same time. The tire mark came when the bike and the down tube continued forward while the fork didn't (after it snapped).

I doubt anyone with rim brakes could ever generate enough stopping force to snap a fork like that. If I'm wrong, I'd love to know the brand of brakes and pads used before I order some again.

Thought I'd get my Internet Analysis in before the OP returned to the site of the crash and confuses us with the facts.

OP: GLAD to see you're getting through it! I managed to wipe my face across the back window of the car. Bloody nose and busted lip. Helmet kept my forehead off the car, thank God.

kostyap

Seeing this stuff made me somewhat disturbed so I went to a friend of mine and showed him this pics. My friend is a former bike racer of many years. Now he owns bike shop where he makes custom steel frames. After looking at pics he said that in his opinion the guy hit large fixed object (parked car, curb, guard rail, whatever ...). He does not believe that the damage can be caused by braking or hitting small pothole/stone.

Myself, I am highly suspicious about such clean cuts / dent combination. Just day before yesterday I decided to test what it feels like riding tires at low pressure. Of course Murphy's law worked as advertised: I hit decent size piece of concrete lying on the road at 20 mph. Well, I got my first ever pinch flat. Bike wobbled slightly for a moment but I did not loose my balance and brought it to stop safely. There was no sign of even slight dent on the rim. So what kind of impact should dent rim that mach, especially with properly inflated tires?

kostyap

I think that they just want to make more money. Not too many people would replace their carbon every 3 years. Too expensive. And if it was truly designed to last that little I think Specialized would be up to it's gills for liability. It is just unsafe design and it is unsafe and negligent to assume that general Joe Schmoe would search for fine print. BTW when I buy my bikes in LBS they come without any manual.

Fleabiscuit

I'm not sure it's about making more money, more like SAVING money. Bike companies don't want to be on the hook for fork related damages so the legal guys add the small print. Just because your LBS doesn't provide a manual, it doesn't change anything. Nothing to do with design or how long they are meant to last, just legal language designed to relieve mfg's of liability.

kostyap

I suspect that if the fork broke in JRA situation and rider got injured manufacturer would be liable no matter what their fine print says.

RaRah

I'm glad you were wearing a helmet. Even still, that looks painful as all get out. I'm checking over my fork today. Good luck man.

JohnDThompson 

Out of curiosity, how did it fail?

Fleabiscuit

I don't disagree with you but if you believe this is a JRA situation, I am a rich Nigerian prince and have a really great business proposition for you! Please forward me your bank account information so I can wire you millions of dollars.

AEO

you guys just have no clue what zertz are... do you...

this is zertz inserts, that bulgy looking thing in the fork. Zertz does not refer to the fork itself, because you can get zertz inserts for seatposts and seatstays as well.

Phantoj

I believe the OP's account of what happened.

This is why: his downtube is buckled in about the middle. When a bike frame buckles from a front impact, the tubes buckle up closer to the head tube, at the end of the butting. That, plus the rubber rubbed off on the downtube, makes me think the fork failed first, then the wheel rode into the frame and buckled the downtube.

kostyap

I do not believe that this particular situation was JRA. I was referring to that 3 years replacement fineprint

kostyap

As a matter of fact I do. What does that have with safety related fineprint?

Fleabiscuit

That's one way of looking at it. I'll give you another (assuming there are rubber marks on the downtube): OP hit something (pothole, small curb, some debris, etc.) that caused fork to snap and the downward force of his weight on the tire caused the rubber mark and the tube to buckle. Something caused that rim to get dented and I'm thinking it's not the downtube.

It seems unlikely both arms of the fork spontaneously snapped cleanly in the exact same spot without hitting anything, causing the wheel to impact the downtube and buckle it, also causing the rim to get that nasty dent. I'm not saying it's impossible and I'm no CSI, just saying it seems highly unlikely.

Fleabiscuit

Same here. Don't know what that has to do with this thread.

lazerzxr

I have to say I love this post! Here we are with everyone worrying about carbon forks and wondering if everything is ok with theirs and someone (me) posts up the manufacturers recommendation on replacement and everyone writes it off as if they know better. People are arguing about zert material as if they think the fork will fail if this secondary structural component goes hard and others telling me spesh just want to make money!

I have no doubt that the 3 years quoted is extremely conservative. I expect dsign calculations pointed at more like 50+ years, then they factor in all the risks and variables and then half the answer and come up with the magic 3 figure probably based on a 100% probability that no failures will occur. They are protecting their business by protecting you. So if the 3 years is exceeded the probability of failure goes up from 0 to something very close to it.

I think carbon fails because people dont know how to look after it and even when presented with a thread like this they STILL make excuses to ignor what the manufacturer tells them because "no one replaces their carbon after 3 years". Well yes, I know they dont, and neither do I but if it breaks on me I consider it to be my fault. I was warned after all.

Having said that I rode a pace suspension fork made of carbon from the late 90s. Had that 11 years and even after it was showing white stress marks in the material it didnt break. If it had of broken, it would have been my fault for riding when it was well overdue replacement.

CPFITNESS

ok we're never going to know what happened because we weren't there. Who cares. Until they start selling bike insurance like car insurance, the dude is screwed. the cost is on him. time to buy a new bike.