Hey guys, would love an opinion on this. I've noticed a crack around the chainstay of my ~8y.o. carbon Look KG461. Is this a big deal? Time for a new frame? The gut instinct says yes. That said, it is at the point where the tube is attached to the lug and there is a corresponding 'lump' on the other side of the frame which has the paint intact. Could it just be a bit of movement in this joint rather than the carbon about to fail and drop me on my ass? Also, the top coat is intact on the inner edge of the chainstay. Fwiw, I had a spoke break about a month ago which caused the rear wheel to jam against the chainstay. Could this have caused the problem?

Cheers guys - love to hear any feedback!

I doubt the broken spoke could have caused the problem. Also I'm not 100% sure you really have a problem, though it looks likely.

Hold the bike up by seat and stem, and put your foot against the center of the right crank, and push it across to the left flexing the frame. Look to see if the crack enlarges or moves as you do so. If not, odds are it's surface damage at the junction, which can sometimes happen if the paint is more brittle than the stays.

In all honesty, I don't expect you'll be so lucky, and that there will be movement at the crack. In that case, the frame is toast, though there are some folks that repair carbon frames. It isn't cheap though, and not all frames are saveable.

There are a number of folks who specialize in carbon frame repair, so you might email the photo to a few and ask if they think they can save it, and a rough (very rough) estimate, to see if it's in your budget ballpark.

When we introduced Trek's first bonded aluminum frame back in the 80s, we got many returns with similar cracks and replaced them under warranty. Eventually, we discovered that this was not a structural failure, but rather an artifact of the fact that the paint was less flexible than the bonded joint it covered, and thus cracked but didn't represent a structural failure.

I'm not saying that this is definitely the case here, but it could be a possibility.

take the wheel out , push on the dropout to see if the crack(?) opens up.

If it is indeed a crack, contact Look to see if there is a lifetime warranty on the frame (assuming you are the original owner and can prove it. You did keep your sales slip, right?). If so they will replace the frame at no cost. If the warranty has a specified time period, like 3 years, they may have a crash replacement policy that provides a replacement frame at lower cost.

Otherwise, new frame time or contact Craig Calfee for a repair estimate.

Cheers for the quick and informed responses guys! Hoping it's just the paint thing because I can't get it to open up at all even by pushing on the frame after taking the wheel out. Lucky I think (especially as I bought it 2nd hand about 5 years ago - no such warranty luck!), but I'll get a second opinion next time I'm at the LBS. Owe you guys one!

If that bonded joint really has failed to some degree you should be able to hear it. What I do on those suspect joints is cover the crack with a little nail polish and go ride. If it's loose it will crack again. Doesn't mean though that it's destined for complete failure.

+1, if it isn't moving, it isn't likely to break suddenly (if at all). As RedDog says, you might want to cover or seal the crack to keep weather out. Either use nail polish or touch up paint, or one turn of electrical tape.