Just spotted this, penny tap and there is no change in pitch, but ..
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Any hints what to do?
It's an old Ridley X-Night, quite new to me, but sold in good faith and owes me very little.
I’d ride it.
Stress the frame and see if there’s any movement. If not stick some resin +/- pigment in there, depending on how worried you are by how it looks.
Crack
It's definitely a crack, the only question is, what's it a crack in? Could just be the paint, could be the whole thing. I'd check my medical insurance and then ride it
I will try the wheel out and flex the stays to see if it visible opens. Marked with a sharpie the ends of it and will monitor. Just spent £600 at dentist this week, I am not looking for a WCA future post.
Any reason not to sand back to the carbon and have a look? Got epoxy and white pigment.
+1 Crack by the look of it - irregular, jaggy shape shows it’s growing slowly but might suddenly go. This area of a frame is usually overbuilt as you’ve got a sleeve joint between the chainstay and BB shell, so unlikely to flex in normal use which probably rules out a paint crack. You could attempt a DIY repair .
You’ll need more than epoxy to repair as the crack indicates movement and broken fibres - over time the stress get distributed between fewer and fewer fibres and so will accelerate. A repair will need to reinforce the joint with an extra few layers of carbon. Easy Composites sell repair kits. No doubt plenty of how to videos on YouTube.
Bonded joint failing .
Possibly due to a void in the joint/ not enough glue in manufacture.
examples of bonded joints
https://www.youtube.com/watch?v=6FYAUa9gzJM