Carbon frame repair (chainsuck)

Having driven my pride and joy rode bike under a metal barrier whilst on the roof of my car, a very friendly clubmate has offered me his specialized tarmac frame as a replacement.

The only problem is the frame has clearly been the victim of a poorly set up front mech and as a result has suffered a lot of chain suck.

To my untrained eye, the carbon doesn’t look damaged, just a layer of paint seems to be missing, but all the paint is missing, down to the carbon.

Couple of questions:

1. Should I get the frame professionaly checked – if so will my LBS be sufficient?

2. If I decide to just wing it, is there any glue/epoxy I can use on the carbon, just to be sure?

3. Anywhere know where I can get a metal chainstay protector from?

Thanks

M

Might be worth contacting someone like this

Carbon Cycle Repairs

I have no experience of them, but they (or someone like them) will probably be in a better position to advise than your LBS….. and if they find anything that is wrong, but repairable, then a it’s probably beyond DIY to make it neat AND structural.

Thanks I did wonder whether the LBS would be best placed to advise.

I would rather spend out on a new frame, then spend £100+ on being told the old one is knackered.

dealt with the above and very professional.

Does carbon break from cracks though? (i.e. in the way cracks propogate in metals)

I thought it was more impacts alone that broke it.

Cracks in the matrix material leads to failure in the fibres leads to collase of the part. Impact is one way in which the matrix cracks arise.

Highly recommend CBR he repaired my very sorry looking roadbike last year after it had an incident with a disposable nappy!!!!!!!! Did an excellent job was very friendly and the bike is still going strong.

FWIW, I’ve a friend who’s still riding his 1995 cf frame which suffered a snapped chainstay as a result of major chainsuck around 1996ish which he then fixed with fibreglass/epoxy and is still being used no probs.

Or if you’re posh/mechanically inept, CBR as suggested.

Just slap a patch of carbonfibre cloth on it using epoxy.

Simple way to check it is to do what’s known as a ‘tap test’. You could send it to an NDT lab to do this, or have a go yourself. Simply put, rap your knuckle on and around the affected area. If you’ve got hidden problems the ‘donk’ sounds will be different on the problem section. What you might be detecting if it’s noticeably different is delamination of the inside layers of carbon etc.

It’s not exactly totally scientific, but it might give you a warmer feeling about the frame.

Thanks all – a few bits to check.

Anyone know where I can get a tough/metal chainstay protector from?

Ta

M