When the time comes for buying second hand bike, we should first confirm that the inner parts of bike is good or not because if inner parts are not good then outlook of bike is just bad.i mean to say bike is looking good or not this is not matter but whats matter is its condition and its performance.now for safety we should first know about the person from which we are going to buy bike.The identity of person, his behavior and other things.by doing this you are safe and get a good second hand bike.