A couple of days ago my girlfriend's bicycle broke. The rear wheel was stuck. Tonight I had finally some spare time to have a look. The bearings had failed, so much so that the wheel must have spun for some time piecewise with the axle.
As a consequence, if you are picturing this right, the left nuts had tighten as that very hot place, whereas the nuts and cup on the drive side were completely loose (the axle had screwed itself to the left).
I don't know what caused this. I had replaced the bearings in the past, something I've done many many times with no problems. What I'm asking here is whether this level of damage is normal or the bearings are cheap. I mean: the rightmost bearing in the picture can be separated into a smaller (about 3/16) inner ball and an outer 1/4" shell!
This is the first time I used bearings from ebay, and would like to have your opinions.