Here’s my thinking. I’m a materials engineer, but I certainly cant predict everything. So here’s my $0.01. My feeling is that with traditional spoked wheels, any carbon rim material failure will likely start at the rim at one or two spoke nipple locations. If that happens, the carbon will give, causing the nipple to pull out a mm or two to relieve stress. This probably will cause the rim to go out of true but the nipple will likely be retained by the rim, I don’t see the rim completely releasing the nipple and spoke.

It’ll likely happen with you on the bike, as that presents more stress than an unloaded rim. Probably the rear rim under heavy acceleration or maybe front rim under heavy breaking and turning.

You’d likely hear the piano string “ping” and the rim would suddenly be maybe 5-10 mm out of true, rubbing the break pads. IMHO, you’re not looking at a catastrophic rim failure situation... but that’s only if the rim really is in as good a shape as you observe it to be.

I’d ride them for a while on basic training rides or fun runs before bombing down hills at break-neck speeds over rough surfaces.

edit: one easy way to tell if any nipples have given up the ghost is a spoke tension tester. Pretty cheap insurance. Of course, the wheel would likely be out of true already.

If you take the rim tape off, can you see the nipples? Are any spokes screwed into the nipples much deeper than the rest? If so, those areas might have yielded a bit, requiring tensioning in the past.

agreed. I’d guess rims might be a better bet than, say, used forks just because the spokes are under tension so if one pulled out you’d see the rim twang right out of true.

I dunno, I have a tough time using old carbon bits, no matter. maybe I’m just old.