An All-Terrain Vehicle (ATV) 4x4 is a four wheeler which is designed for off-road use and to be driven on all kinds of surfaces. A 4x4, also called a four-wheel drive implies an engine system in which the power is transmitted to all four wheels. This gives the vehicle the power to climb steep slopes and also to navigate hilly and uneven terrain. In 1986, Honda released the FourTrax TRX350 4x4, a versatile vehicle, which pioneered the popularity of the four-wheel drive and prompted other manufacturers to churn out similar vehicles. These four-wheelers acquired a broad customer base among outdoors enthusiasts such as ranchers, farmers, hunters, and construction site workers. The four-wheel drive system is ideal in situations where there is a low traction surface, such as on mud, loose gravel, or even ice. The biggest challenge faced by the four-wheel drive creators was to account for the differences in the rotating speeds of the wheels when the vehicle was not moving in a straight line, as when the driver is making a turn. To enable smooth driving, a differential is used, which is a device having gears that which allows one input shaft to drive two output shafts. Thus, the angular force (torque) is distributed evenly to all the wheels, even though the angular velocity of each wheel may differ. Four-wheel technology was born in 1903 in the form of the Spyker 60 HP, a car designed by the Dutch brothers Jacobus and Hendrik-Jan Spijker. A century later, the 4x4 ATVs today, have state-of-the-art mechanics with V-twin engines, offering smooth riding with deft control and navigation. ATVs are normally classified in the same group as other off-road vehicles such as dirt motorcycles and jeeps.