Every time I ride ether of my bikes I go over the entire bike and check to make sure everything is good.

This was just weird because he rode it yesterday all day and then about 30miles to my house this morning with no problems. I think the bearing was bad before we tightened the chain because the axle nut was kinda loose. He tightened the chain then the axle nut and everything was fine until he used his rear brake. I'm really glad it decided to fail before we hit the mountains.