UKC

Both me and my wife have road bikes with carbon forks. They are both about 10 years old and have had moderate use, me because Im mainly a mountain biker and she because of a long term illness, but they haven't had a particularly hard life. When my wife had her bike built, the bike shop mannie told us that the forks should be changed every 3 to 4 years depending on use. Given that time is long overdue, does anyone have any tales of fork breakage to convince us of the wisdom of replacing them? I've had a good look at them both and there doesn't appear to be any signs of weakness, but that of course is no guarantee that there isn't a small crack somewhere waiting to propagate!
Any tales of woe or otherwise welcome.

In reply to pamph:

I've been cycling my whole life and never heard anyone say that. Sounds like rubbish.

In reply to pamph:

Was recently on a long ride with a mate and talking about his Chinese bought carbon forks. In his words 'they've got a big crack in but it's been like that for ages and they seem ok'.

I'm not convinced about his logic, but for a healthy looking all carbon fork that hasn't been in a crash I wouldn't worry about age. They won't fatigue in the same way as aluminium, and as far as I know neither the resin nor carbon fibres should degrade with time.

In reply to pamph:

More in depth discussion of the issues here https://cyclingtips.com/2015/08/what-is-the-lifespan-of-a-carbon-frame/

In reply to pamph:

Never heard that before. Or heard about fork breakages for that matter.

In reply to pamph:

I was wondering the same about my commuter, a 2011 trek that's had a relatively hard life.
Not as old as yours but it sounds like mine will have had a lot more wear.

In reply to pamph:

Ha ha - someone's pulling a fast one.

My old carbon road bike is around 12 years old and I've not considered changing the forks yet. There's a bit of bobbling of the paint around the crown that I'm keeping an eye on, but they seem ok at the moment. That includes hitting a pothole hard enough to crack the rear rim a few years ago.

In reply to pamph:

Never heard so much rubbish, which shop is this ?

In reply to pamph:

Carbon is massively stronger than metal weight for weight and as far as I know isn't fatigued by repeated stressing. Carbon frames and forks sometimes develop witness cracks where the brittle laquer finish shows hairline cracks in places where there's flexing but in all the years I've been cycling I can't remember ever hearing of a carbon fork breaking. I had some eXotic carbon forks on my mountain bike and they were super smooth riding and as strong as anything else, even when I repeatedly endoed the bike on the front brake.

In reply to pamph:

youtube.com/watch?v=w5eMMf11uhM&

In reply to Yanis Nayu:
Apart from the Australian man who died when his forks broke.
http://www.cyclingweekly.com/news/latest-news/cyclist-died-carbon-forks-sep...
Those these were bonded but I think it is such a crucial component caution is best.

In reply to Rigid Raider:

Enty who used to post on here, (he runs a cycling holiday business in France), mentioned a friend with carbon forks having his forks break while cycling along and needing dental treatment, leading to him always replacing anything on the front of his bike which is made from carbon if it ever gets knocked.

A relative who was into metal fatigue (and still is now retired), diversified his company into predicting rubber and plastic and carbon fatigue, and he learnt that what 'can' happen with carbon frames is that, if given a big enough impact, there can be damage hidden within the frame, which may lead to a breakage later on. Any company worth it's salt would design around that, though.

If one worries about this kind of thing, the way different materials fail is quite interesting, with steel failing in a way which gives one some warning, if you vaguely look after your bike and clean it etc you'd be able to notice any cracks beginning to form, compared to carbon which will generally suddenly 'let go'.

In reply to Timmd:

I would expect decent carbon to be considerably better than decent aluminium in terms of longevity before catastrophic failure. If anyone's really worried about it, I'd recommend a steel or titanium fork/bike.

In reply to blackmountainbiker:

On the list of ways I might die cycling, I don't think this one will concern me; certainly not above being wiped out by a delivery van.

In reply to Timmd:

Different usage but a friend of mine who was into windsurfing had a mast collapse on him through carbon fatigue so those saying carbon doesn't fatigue, sorry bu anything fatigues. More relevant with carbon is lay up and jointing. Aluminium and carbon both break suddenly and without warning because thier yield strength is so close to the Ultimate Tensile Strength whilt Steels generally (especially the sort of grades you'd be talking about) have YS and UTS which are relatively far apart, i.e. it will bend before snapping. I believe the same is true with many grades of Ti.

In reply to beardy mike:


Though windsurfing tends to involve a lot more crashing than cycling (or a least when I do it), and I'd be surprised if the stresses on a bike frame (in normal use) match those typically imposed on a windsurf mast.

In reply to Sam W:

That's an interesting article, and I suppose the bottom line is that carbon is super strong and reliable providing that it is made properly. Given that my forks (and my wife's) have lasted this long without problems, and have not had any hard knocks it's safe to assume they are ok?
To the replies suggesting that the bike builder's advice was rubbish, it is possible that 10 or more years ago perhaps the longevity of carbon forks was not so assured, and he was covering his back? Or perhaps he wanted to sell us more forks after a few years? But that's the cynic in me.
My original post should have said that I was after any stories that people had heard about fork failure rather than any definitive proof. But thanks for the replies, all.

In reply to TeeBee:

Well OK apart there are atleast 2 stories from people with direct evidence on this thread in only a few replies... so it can't be complete horse muck can it

In reply to beardy mike:


Presumably from people trawling the internet. There are a lot of carbon forks around doing millions of miles.

In reply to Yanis Nayu:

Enty was a regular here - doubt it was just hearsay and the chap who broke his face was just making it up either. All I'm pointing out is that can happen. Just like others here saying aluminium is weak are talking bollocks. Must be even more alu forks out there not breaking.

In reply to beardy mike:

I can't say it worries me. However, could have done with this thread a week ago as justification to my missus for the money I've just spunked on a super-aero race weapon.

In reply to Yanis Nayu:

It's never too late to justify something.

In reply to Timmd:

I just went with "I really want it", which in reality is most people's justification for buying most things)))

In reply to beardy mike: would you rather, from a reliability viewpoint rather ride carbon or Al forks? Carbon for me - seen too much cracked Al on frames to trust it on fork arms

In reply to wbo:

One of the places you can expect cracks to form on metal frames is at the wields, at the top of the seat tube where the little bit of tube sticks up to hold the saddle, and at the bottom of the down tube where it meets the BB, and at the drive side chain stay too.

In reply to Timmd:


All the cracked Al frames I've seen had cracks in the down tube a few inches from the head tube weld.

My concern with my carbon forks is two fold in that they have a bonded Al steerer tube and I can see marks/cracks running lengthways in the paint/clearcoat.

In reply to wbo: can't say id be terribly fussed either way. If its road riding, a weight is the only factor, carbon. If its offroad and gravel, my straight legged steel forks are never going to break... but then again, my ancient rockshox Sid forks wont give me trouble either...

In reply to Sam W:


Hope you made a fuss and told him to change them? That's dead scary.

In reply to Timmd:

Yes, I made a fuss but he's not going to change them. He's an engineer and should know better, given the consequence of failure it's certainly a risk I wouldn't be willing to take.