Carbon fork (micro)fractures - how to detect?

[Niblox]

Hi all

Can anyone advise me regarding the folliowing. Recently a colleague of mine was seriously injured in a cycling accident where (reportedly) the carbon front forks on his road bike fractured at high speed and he was thrown off, fracturing 3 neck vertebrae. He is currently in a medically induced coma and the prognosis is uncertain.

Some people I have been talking to have suggested getting carbon fibre bikes laser scanned to check for microfractures which can suddenly turn into a catastrophic failure. Is this recommended? If so, where can you get it done?

Any information would be helpful. I have been looking at my carbon fibre road bike in a different light the past few days.

 

[fossyant]

You can't easily get them scanned really - too expensive.

Had the bike been previously crashed ? Carbon is just as reliable as any other material

 

[smokeysmoo]

Carbon is just as reliable as any other material

Unless it's been crashed as Fossy says, or exposed to sunlight, or ridden in anyway what so ever

 

[Monsieur Remings]

Unless it's been crashed as Fossy says, or exposed to sunlight, or ridden in anyway what so ever

Is this really the sort of thread to make your point about carbon?

Sorry to hear about your colleague Niblox. I guess you'd have to have it tested so regularly as to make it impractical to do so.

 

[PK99]

Hi all

Can anyone advise me regarding the folliowing. Recently a colleague of mine was seriously injured in a cycling accident where (reportedly) the carbon front forks on his road bike fractured at high speed and he was thrown off, fracturing 3 neck vertebrae. He is currently in a medically induced coma and the prognosis is uncertain.

Some people I have been talking to have suggested getting carbon fibre bikes laser scanned to check for microfractures which can suddenly turn into a catastrophic failure. Is this recommended? If so, where can you get it done?

Any information would be helpful. I have been looking at my carbon fibre road bike in a different light the past few days.

The information that came with my specialized tricross recommended replacement of carbon forks after 3 years

 

[smokeysmoo]

Is this really the sort of thread to make your point about carbon?

I wasn't attempting to make any point about anything.

It was a light hearted comment perfectly demonstrated by the whistling smiley. In fact, the same sort of comment that loads of people make, (light heartedly also) about cf on an almost daily basis.

Don't read too much into things

 

[Niblox]

Hi Folks

Thanks for those replies. The best thing seems to be to replace the forks every few years. Has anyone come across this problem of fracturing forks?

Any thoughts about the frame? Is it true that exposing it to sunlight causes problems? Would the paint covering not be enough to protect it?

 

[smokeysmoo]

Hi Folks

Thanks for those replies. The best thing seems to be to replace the forks every few years. Has anyone come across this problem of fracturing forks?

Any thoughts about the frame? Is it true that exposing it to sunlight causes problems? Would the paint covering not be enough to protect it?

1. Don't replace your forks unless you've crashed heavily ad have concerns as a result.

2. Are you having a laugh? My comments about the sun were a joke, nothing more, nothing less. The smiley I used denotes irony/humour. Don't worry about it

 

[Rohloff_Brompton_Rider]

Hi all

Can anyone advise me regarding the folliowing. Recently a colleague of mine was seriously injured in a cycling accident where (reportedly) the carbon front forks on his road bike fractured at high speed and he was thrown off, fracturing 3 neck vertebrae. He is currently in a medically induced coma and the prognosis is uncertain.

Some people I have been talking to have suggested getting carbon fibre bikes laser scanned to check for microfractures which can suddenly turn into a catastrophic failure. Is this recommended? If so, where can you get it done?

Any information would be helpful. I have been looking at my carbon fibre road bike in a different light the past few days.

i'm really sorry to hear about your mate, i hope he pulls thru. the crux of the matter is this, cf damage is not easily detected by joe public. i understand your thinking about your cf bike, i too have had a bad accident with cf failing, i've read and watched all the info about how cf is stronger than other materials. BUT i still feel very very nervous about riding with cf forks (my failure was a ridiculously expensive cf mtb frame) hence my reason for selling my beautiful cx bike, i just don't feel totally relaxed on cf.

once again i hope your mate pulls thru.

 

[Wobblers]

Hi all

Can anyone advise me regarding the folliowing. Recently a colleague of mine was seriously injured in a cycling accident where (reportedly) the carbon front forks on his road bike fractured at high speed and he was thrown off, fracturing 3 neck vertebrae. He is currently in a medically induced coma and the prognosis is uncertain.

Some people I have been talking to have suggested getting carbon fibre bikes laser scanned to check for microfractures which can suddenly turn into a catastrophic failure. Is this recommended? If so, where can you get it done?

Any information would be helpful. I have been looking at my carbon fibre road bike in a different light the past few days.

That sounds nasty. I can only hope your colleague makes a full and speedy recovery.

Without a careful microscopic examination of the forks by a materials scientist, it's going to be very difficult to determine whether the damage was the cause of the crash, or simply a result of the crash. If fork failure was the cause, then there's two most likely explanations: delamination either due to a manufacturing defect or due to previous impact damage. I'd rather hope that most manufacturers would catch any defective carbon before it left the factory: with any reputable brand, any such defect would almost certainly be caught by quality control inspections. Of course, you can't be 100% sure that a defective part will never be missed... But it's not just carbon that could suffer such manufacturing defects, so can steel, alloy or titanium: poor welds, improper heat treatment, hydrogen embrittlement, lack of control of alloy composition could all cause such catastrophic failures too. But it is rather rare, and carbon fibre certainly isn't less safe than a metal part - its use in aerospace over the last 20 years testifies to that.

Inspection of carbon parts would first be a visual check to see if there's any visible damage followed by an ultrasound examination to check for internal voids (which would indicate delamination). But if you've never crashed a carbon part or subjected it to impact, there's very little to worry about.

 

[Wobblers]

i'm really sorry to hear about your mate, i hope he pulls thru. the crux of the matter is this, cf damage is not easily detected by joe public. i understand your thinking about your cf bike, i too have had a bad accident with cf failing, i've read and watched all the info about how cf is stronger than other materials. BUT i still feel very very nervous about riding with cf forks (my failure was a ridiculously expensive cf mtb frame) hence my reason for selling my beautiful cx bike, i just don't feel totally relaxed on cf.

once again i hope your mate pulls thru.

Carbon fibre is much stronger than any metal alloy, weight for weight. The problem is that it's also much more brittle. Think of the difference between a metal mug and a glass - which is more likely to survive being dropped? That's why any carbon part that's been subject to heavy impact should be considered suspect and inspected.