OMG! How serious is this crack?

Globalti

Legendary Member
Carbon Specialized Roubaix. Just spotted this during a routine clean/fettle. It's in the chainstay and doesn't go all the way around. Looks like just the lacquer that's cracked.... what do you think?

P1050999.jpg
 

ianrauk

Tattooed Beat Messiah
Blimey mate... straight down the LBS with that I reckon. See what they say.
 
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Globalti

Globalti

Legendary Member
Just been round to see a neighbour who's a very experienced roadie and bike builder and he says it's just at the point where the ali dropout enters the carbon tube so you would expect to find some flexing there. It is probably the most stressed point on any bike frame, apart from the forks. There seems to be an accumulation of long-term dirt in the crack, which would tell me it was quite long-established. If it was new with fresh paint or carbon visible I'd be blaming it on the new stiffer wheels I've just bought.

I've tried squeezing the dropouts together and there's no sign of movement or creaking sound.
 

RecordAceFromNew

Swinging Member
Location
West London
The crack suggests the structure of the dropout to look like this.

The crack indicates that there has been relative movement between the dropout and the horizontal stay. The question, then, is whether it is reasonable to expect this particular joint to have been as solid as a weld.

From the way it is constructed and finished, I would expect the answer is yes. As such I agree with what Ianrauk suggested.
 
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Globalti

Globalti

Legendary Member
Useful link, thanks. If that's the case and if the crack progresses then the joint separates cleanly, I reckon it might just be possible for a carbon specialist to re-bond it.

Big hilly ride early tomorrow morning, I'll keep an eye on it.
 

Steve Austin

The Marmalade Kid
Location
Mlehworld
fubar'ed imo
 
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Globalti

Globalti

Legendary Member
I think ColinJ is right; I think the bike was thrown off the bridge and landed on its back wheel, which was badly bent. If the back wheel took the impact, that could have shocked the lug where it enters the chainstay.

Ironic, isn't it that a few days ago I posted on this thread about repairing carbon frames: https://www.cyclechat.net/

I have emailed the picture to Specialized and will contact the bloke recommended in that thread to get his opinion as well.
 
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Globalti

Globalti

Legendary Member
Another update: just spoken with this bloke: http://www.carboncyclerepairs.co.uk/ who says it's almost certainly what he called a "witness crack" in the very thick brittle paint and lacquer layer. Says he's seen loads like this and had loads of panicky phone calls from blokes like me. He says that if the manufacturer didn't paint the joint between the lug and the frame nobody would have these scares. He says that inevitably there's flexion at the joint and that unless it spreads or I hear creaking it's nothing to worry about.

I will wait and see what Specialized say about it on Monday and report back.
 
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Globalti

Globalti

Legendary Member
Thought forum members might be interested in an update on this, since it could affect a few of us with carbon frames.

After three months of heavy summer use including banging across many cattle grids, some rough top-dressed tarmac and some big out-of-the-saddle climbs the crack has not grown or changed one little bit; it is absolutely identical in size and shape to the picture. There is no movement or creaking so I feel increasingly confident that the carbon specialist's diagnosis of a "witness crack" was correct.

Phew.
 

MrRidley

Guest
Location
glasgow
I would say get it checked right away, i've got a post below in which the same happened to my Ridley, to it back and they swapped it no problem, it also didn't look as bad as yours.
 
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