I have an unneeded disk wheel. The rim is "disk-only", but it has sidewalls just as though it was for rim brakes. The sidewalls are painted though and not machined. (I even suspect it's some older model re-labeled with "disk-only".)
What can go wrong putting it in a rim-brake bike? After a few first slowdowns, while I take some care, the paint wears off.
Can sidewalls of "disk-only" rims, while looking just like their old rim-brake-compatible counterparties, be significantly thinner or otherwise unsuitable for using with rim brakes?
I'm looking for facts, not guesses or hypotheses (which I have more than enough myself :-) )