Pls keep an eye on your carbon forks/frames/bars!

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redefined_cycles
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Pls keep an eye on your carbon forks/frames/bars!

Post by redefined_cycles »

https://road.cc/content/news/cyclist-pa ... 10m-305347 little bit worrying really and reminded me of my Sonder pile of sub standard snapping at the chainstay. Also, yesterdays ride (before I read this article) had me questioning the amount of deflection on my aero Specialized handlebars. It was most likely in my head and due to the cold weather affecting my thinking.

But, suffice to say, if you have some carbon Planet X forks, do keep an eye out. Lawyers claim they're tested to appropriate standards (which they probably are) but you can never risk a last thing Friday batch. Or, first thing Monday morning 'hungover' build :smile: (no offence to anyone hungover on a Monday morn :-bd
yourguitarhero
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by yourguitarhero »

I feel that this kind of incident is one of those ones that is so without warning and also so statistically unlikely that it can't be mitigated against other than by not riding a bike. But then, if you were to do that then you wouldn't live life at all - people die loading the dishwasher or tripping while walking down the street.

I really don't mean to diminish what has happened to this guy - being paralysed is almost unimaginable - it is a horrible thing that has happened to him and I have no idea how I would cope with it.

But I don't think it would make me change my behaviours. Or not ride something made of carbon.
jameso
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by jameso »

To be fair to Planet X they source from suppliers who make frames and forks for a lot of brands.

But yeah, inspect stuff from time to time. The topic came up on STW and there's people saying essentially 'anything can break' and it reminded me that in the summer I found a 2″ crack on the bend of an Al bar that I’d had on a gravel bike for 3-4 years. Sweat corrosion under the tape ate into the surface and started a crack. That would have been a fairly dramatic moment when the crack grew to a total failure as it was hidden under the tape. That's what I like about metal kit, if you look for the signs it gives a warning before it fails.
I feel that this kind of incident is one of those ones that is so without warning and also so statistically unlikely that it can't be mitigated against other than by not riding a bike.
A serious crash and outcome might come from something else like a blown out tyre or a stem face plate going, I agree. Still, imho carbon forks might raise your risk over a steel fork if that's an alternative, by how much is hard to say. My experience of cracking or raking out a few steel forks says I trust them to remain rideable even when they're past the point of no return. It's about how things fail. And in all this I do have a bias (from experience at least..), I really like steel as a material and I think carbon is horrible stuff, so what I say should be read with that in mind : )
Last edited by jameso on Tue Nov 28, 2023 9:52 am, edited 1 time in total.
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Bearbonesnorm
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by Bearbonesnorm »

As said, not just carbon. Anything can break and I suppose many items get a somewhat harder time when other things are strapped to them / hanging from them. I say check things from time to time but don't become paranoid.
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Lazarus
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by Lazarus »

Agree with you both but carbon is the more likely to fail without warning/ obvious signs of fatique( but never snapped either) .
I do use carbon but assume that being 10 stone I am well away from its threshold weight.

That incident juat seems like the law of averages*. One fork in a million will just fail( cannot see a steel one snapping at the steerer though)

* I would also sue as its clearly was not fit for purpose
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whitestone
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by whitestone »

Everything has a finite life - technically it's called MTBF (Mean Time Between Failure). As James says, the makers of the forks will be a CF specialist who supplies a lot of bike "manufacturers" amongst other things, a bit like car component manufacturers who might make a fuel gauge that goes in a Ford Fiesta and a Rolls Royce. They may use older lays for the lower end of the market and newer more complicated lays for the top end bikes, in a way the older lays are likely to be more reliable as they wouldn't still be using them if they weren't, though something like changing standards/regulations might force their retirement from the production line.

There's also the "newsworthy" aspect to consider - there could be a hundred thousand or a million of those forks in use worldwide without issue but one accident (with horrible consequences) is worth reporting.

CF is, in material terms, brittle and will "just break" whereas steel is ductile, that is there's some give before it breaks - I've seen steel frames with wrinkles in the tubing that are still structurally sound. The US Marine Corps use carbon fibre wings on their Harrier Jump Jets, in fact they are still in service a decade or more after the UK retired their Harrier fleet (politics might have a role in that retirement not just airworthiness), I don't have a tame USMC service engineer to ask about service intervals and replacement cycles but they must have a strong case for keeping them in use.
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redefined_cycles
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by redefined_cycles »

Don't get me wrong (and I'm sure no one did) I'm not planning to stop riding carbon. Just good to check it over. Even the Cannondale CAAD 12 and beyond (lightes alloy frame on the market I think) frames are probably on the higher probability stakes of failure due to the ultra thin walls of the alloy used.

Just a reminder to keep em checked over. Since I started noticing the deflection on my bars I didn't put to much wieght on the drops - but it was probably all in my head. Sorry for that chappy who's forks snapped. Reminded me of what Jameso said ages ago about how he doesn't get on with carbon.
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Loki
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by Loki »

my favourite thing to see when I was working as a mechanic was the effects of running your headset loose on a fork with a carbon steerer or the occasion when internal cables wore through the frame walls, then again I have also seen internal cables wear through a Campag crank axle being cut in two by internal cables, everything fails, the more fragile the material, the better designed it had better be.
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jameso
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Re: Pls keep an eye on your carbon forks/frames/bars!

Post by jameso »

Even the Cannondale CAAD 12 and beyond (lightes alloy frame on the market I think) frames are probably on the higher probability stakes of failure due to the ultra thin walls of the alloy used.

Just a reminder to keep em checked over.
1 thing worth remembering generally is how metal bike parts tends to fail via cracks that are visible before they break but carbon is more likely to fail due to internal flaw growth that we can't see. I think my dislike of carbon is partly about that hidden fault potential, it's similar to why I prefer trad shifting where I can see it all working (or why it's not) rather than the potential hidden faults in electronic gears. Zen and the Art of Motorcycle Maintenance.. I like things I can understand and work with, some prefer things that are all the bells and whistles and tech and don't need to know what to do if it goes wrong, neither is necessarily right or better.
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