My rear tire was keep going flat while riding, so I felt around the tire for any punctures or abnormal ‘signs’ that may be causing the problem. One area felt too thick, and at first, I thought I just overinflated it and somehow the air got trapped. Later, I ended up pushing my bike into the rocks, and when the tire tread came off, I saw that the inner tube had literally folded up into a ‘Z’ shape inside the tire. How did this happen? I have never seen anything like this before.