Agreed, not a tubular thing. But it is a sign that the rim is good and worn. There might be plenty of life left or they might be ready to crack. I'd advise keep riding, keep an eye on them. They'll be worn out when they start to bulge or you feel the pulsing while braking.

You're not looking at impending doom, you're looking at more frequent maintenance to keep them true, and eventually it won't be worth the hassle.


This tubular rim was definitely at end of life Mavic GL330 .
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