The two most common quad bike models are racing quad bikes and all terrain vehicle (ATV) quad bikes that are more utilitarian. A racing quad bike will generally be lighter than other types of ATV models, and the specific components are designed for the rigors of racing. More utilitarian quad bike models are often much larger and heavier, and they are meant to perform extra duties such as hauling large amounts of weight, towing, and traveling longer distances. Racing models are also typically two-wheel drive, while ATV models are very often four-wheel drive. Other models of quads exist, such as amphibious quads or modified sport utility quads.
A racing quad bike will usually be two-wheel drive, much lighter than other models of quad, and feature a lower center of gravity for quick cornering and stability. The components of such a quad bike will be designed for effective racing; suspension, for example, may be adjustable to accommodate a course with several jumps or a flatter course with muddy conditions. Tires can also be replaced to suit the conditions of the race course. The engines are designed to have high power output to enhance speed capabilities during racing.
More utilitarian ATV quad bike models are bulkier and less adapted for speed. They are designed with strength, comfort, and usability in mind. An ATV quad bike may feature gear racks or gun racks, more paneling and fairing to protect the rider and the bike from mud and debris, accessories such as winch systems and trailer hitches, and other convenient features such as rear view mirrors and headlights. Such quads are almost always four-wheel drive to accommodate for rough terrain and excess weight being carried on the vehicle. It is not uncommon to see models with automatic transmissions rather than manual transmissions common on other types of bikes.
An amphibious ATV is one that is designed to handle both off-road capabilities as well as water capabilities. They are useful in swamps and marshes, and while four-wheel models do exist, they are quite rare. Six or eight wheel models are more common, and some amphibious vehicles even feature tracks similar to those of a tank rather than wheels.
Sport utility ATV models are often styled after utilitarian models, but they sometimes feature other types of conveniences, such as protective canopies and seating for more than one person. Most quad models are meant to be ridden by only one person, but sport utility ATVs sometimes feature longer wheel bases that allow more rider room to accommodate a passenger and driver.