Opinions on this carbon frame damage?

neeb

Crashed in a bunch yesterday and apart from the road rash and wonky wheels, bent derailleur hanger, scuffed saddle, bar tape, levers and derailleur (all of which are repairable/cheaply replaceable or no big deal), the frame picked up a nasty impact on the top tube, probably from the bars coming round and whacking it very hard...

I think it looks a bit worse than it is because the lacquer is quite thick and has cracked/crazed dramatically, but the biggest bit of exposed carbon looks like it has been gouged a bit (see last picture). Either that or it's a crack masquerading as a gouge. Must admit I can't think what could have gouged it if it was a result of the taped bars hitting it.

Wondering whether to 1) expect the frame to fall in half the next time it is ridden 2) just see it as cosmetic damage, stick a piece of white masking tape over it and forget about it, or 3) something in-between...

It does somehow seem unlikely that the whole top tube (which is pretty chunky) is suddenly going to break in half without warning. If I tap the carbon it sounds exactly the same in that point as in others. I can sit in the top tube with my whole body weight without hearing anything creaking. Pressing the carbon over/right next to the damage doesn't cause anything to bend or give way.

trooperk

You need to peel away the flaky bits for a better inspection.

neeb

trooperk wrote:

You need to peel away the flaky bits for a better inspection.

Yup, good idea, will do.

Semantik

I am no materials scientist but if it was my bike I would be looking at getting that damage repaired rather than ignoring it/carrying on riding it.

Monty Dog

It's what known as a 'bruise' and could result in delamination of the underlying layers and therefore a weakness of the structure. If there is no crack, then it could probably survive for many years. Options probably include a reinforced ' bandage' on the outside or injection of structural PU foam internally. Suggest you speak to a carbon repair specialist to see what the options are - the most expensive bit could be a respray if you don't want to live with the damaged paintwork.

A friend cracked the seatstay on her Madone due to a crash - it's left a full-thickness longitudinal crack that you can squeeze with your fingers. Still racing it 2 months later...

neeb

Thanks for the tips - I've emailed a reasonably local carbon repair specialist, hopefully I can get it looked at.

Yeah, "bruise" seems like a good description. I tried peeling away some of the paint and what happens is that the white paint layer, where it is loose/cracked, comes away with a thin bit of carbon attached, so I guess that is localised/superficial delamination. It still seems solid enough, the carbon is pretty thick. I do find it extremely hard to believe that the whole top tube could suddenly pop in half in an instant without any warning or signs of cracks spreading, but what do I know...

Monty Dog

Press the damaged area firmly with your thumb - does it move or is it as stiff as the rest of the tube?

pinno

Monty Dog wrote:

It's what known as a 'bruise' and could result in delamination of the underlying layers and therefore a weakness of the structure. If there is no crack, then it could probably survive for many years. Options probably include a reinforced ' bandage' on the outside or injection of structural PU foam internally. Suggest you speak to a carbon repair specialist to see what the options are - the most expensive bit could be a respray if you don't want to live with the damaged paintwork.

A friend cracked the seatstay on her Madone due to a crash - it's left a full-thickness longitudinal crack that you can squeeze with your fingers. Still racing it 2 months later...

I bought my Wilier as a damaged frame. There was an inch and a half crack down the seat tube. The guy who rode it before me weighed 85kg's and the crack did not get any bigger after 3 months of riding it with the crack held up by the seatpost clamp. I am a lot lighter but I fixed the crack myself with a kevlar patch and resin from a fibreglass kit.

On the OP: A Carbon specialist will x-ray the tube to see if there has been any delaminating/structural damage.
These boys gave me good advice:

http://www.carboncyclerepairs.co.uk/index.html

neeb

Monty Dog wrote:

Press the damaged area firmly with your thumb - does it move or is it as stiff as the rest of the tube?

That's the thing, despite the damage it feels the same as the rest of the tube. Sounds the same when tapping it too.

dowler5959

I am going through the same thing currently. I laid my bike down causing the damage shown in the picture. Took it to the bike shop and they sent pictures to trek. The first trek guy wasnt sure, the second said he saw no damage. The bike shop owner did the squeezing and tap test and found it not to be damaged and the bike was given a clean bill of health. Now I guess I just need to quit obsessing about it and ride the stupid thing which is proving easier said than done.

neeb

At the end of the day (just as with my frame), it's on the top tube, which isn't really subject to the sort of massive leverage that is likely to make a damaged tube suddenly snap in half without warning. Also (at least in my case), it's right under my nose so I can keep an eye on it..

On the other hand, if the damage I have on my frame was on the forks or chainstays, or maybe even on the downtube, I wouldn't even consider riding it without getting it checked out.

dowler5959

Yeah, I bought some white-out to mark the edges in order to be able to quickly tell if the crack changes