I am ashamed to admit that up until now, I have not known how to change a flat on my bike. I would head off on rides hoping that either I did not flat, could call someone to come get me if I did, or rely on the other people I am riding with to know how to change it for me. Fortunately, I have yet to experience a flat when riding (knock on wood), but I know it's inevitable. Therefore, I should know how to change a flat tire by myself.