BMX stands for bicycle motocross. This type of bicycle is an off-road sport bicycle and used for racing and stunt riding. BMX bikes are designed for shorter sprints and stunting as opposed to mountain bikes that are made for longer trail riding with rougher terrain. The frames of BMX bikes are smaller, lighter and sturdier than others. The knobby, thick tires allow for them to grip rough terrains and allow for higher impact. This type of bike can be used for around-town riding but is mainly used for stunt off-road riding.