I haven't seen this one mentioned before, but it's the second rim I've done this to.
Lots of us have popped a spoke or three.
The urban riders may have pac-manned a rim on a curb.
The offroaders have likely pringled a rim or two.
How many other people crush the braking surface like a pop can? Literally, pinch it inward so that the bead is splayed out at the top edge if you looked at a cross section?
I know what caused it: I've got around 5500 miles on this rim, year 'round in the PNW. That means wet road grit. That means sand and cinders. All those lovely things which wear down a rim quickly. Between the metal getting thin, and the wide profile uber-strength cantis, and all the hills I have to stop my 250 bulk at the bottom of, the rim got worn and finally started to warp!
So, how about it... anyone else crushed a rim like a pop can?