Checking over a carbon road frame + fork after a crash

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Checking over a carbon road frame + fork after a crash

12 posts & 10 voices | Started 2 years ago by Taz | Latest reply from phyncra

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Taz - Member

After a big stack in Novemeber I want to get back on the road bike.

I have looked over the bike and fork closely and had a quick spin up and down the road. Before going off further afield how do I convince myself all is well? What checks should I be doing over and above the close look over for surface damage.

The main impact was front on into another rider if that makes any difference. The front wheel had a slight,easily trued buckle. No other obvious damage

It's a Planet X Road SL (again just in case it is relevant)

Thanks

Posted 2 years ago #
leggyblonde - Member

x-ray is the only real way you can be sure there is no below-surface damage with carbon unfortunately.

Posted 2 years ago #
beaker - Member

You could try tapping a coin on the surface, any change in tone would indicate delamination (I think).

Posted 2 years ago #
AndyRT - Member

but the change in tone could also mean where internal butting may be placed, so not really an effective test I fear.

If you need any reassurance, it seems that carbon does not snap like metal, so if it does fail, it will be lots of creaking, followed by a loss of structural cohesion, unless you hit something again, in which case, any weakness will be likely to be exploited by the energy, as it tries to dissipate through the frame..

Posted 2 years ago #
Taz - Member

Thanks guys. I figured that creaking may be a leading indicator and there was nothing on my short spin. My sense is all is well but still a niggling doubt and I certinaly do not wish to be proven wrong on a 40mph downhill

Posted 2 years ago #
Swalsey - Member

Take it to you lbs, explain how you stacked and get their opinion.

Posted 2 years ago #
citizen kane - Member

Ultrasonic inspection would be the best but would be increadibly expensive to have done and you probably need a finger print of the frame pre crash to make any sense of the results.

Conventional X ray will tell you virtually nothing, carbon is nearly transparent to x-rays and they will only image total thickness changes. Radiography can work on surface breaking cracks or impact damage if you can introduce a radio opaque penatrant that will wick into the damaged fibres and delaminations..

Posted 2 years ago #
aP - Member

If you feel uncomfotable riding it then get rid of it.
2 years ago i had a pothole/ wall/ road/ wall/ road moment whilst out on my road bike. Once I'd got back from hospital and could face looking at my bike I changed the forks, stem and bars (WR compositi - I nearly cried) as I had lost confidence in them. Only cost me about £450.00 as I couldn't justify those bars again :o( - however I have confidence in what's on the bike now and ride it a lot.

Posted 2 years ago #
leggyblonde - Member

interesting citizen kane, thanks.

Posted 2 years ago #
crikey - Member

Good grief, get on it and get it bloody ridden!
Ultrasonics, xrays, coin tapping nonsense; I've stacked my carbon roadie 4 times and just rode on. There's so much rubbish talked about carbon frames, I've broken two alu, and three steel ones...

Posted 2 years ago #
shedfull - Member

Use the tap test. After all, it's used to tell Airbus whether the composite tail of your holiday aeroplane is about to drop off: New Scientist

Posted 2 years ago #
phyncra - Member

the fact is is planet X is very relevant. Those forks soo flexy they are terrifying to ride in any state!

Posted 2 years ago #

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