In its original form, the wheel is a round block made of hard and durable materials, in which a round hole is drilled in the center, through which an axle bearing is placed. When the moment acts on the wheel under the action of gravity or torque, the wheel will rotate around the axle. Rotating around its axis makes one of the six simple machines one. When placed vertically under a load-bearing platform or box, wheels rotating on a horizontal axis can carry heavy objects. When placed horizontally, the wheel rotating on its vertical axis can control the rotation movement of the molding material (for example, the wheel of a Potter); When it is installed on the column connected with the rudder or on the chassis mounted on other wheels, it can control the direction of the ship or vehicle (such as the wheel or steering wheel on the ship); when it is connected to the crankshaft or engine, the wheel can store, release or transmit energy (such as flywheel).

The driving wheel is the wheel of the motor vehicle, which transfers the torque from the tire to the traction to the road surface, so that the vehicle can drive. The powertrain transmits enough torque to the wheels to overcome the static force, causing the vehicle to move forward or backward.

Two wheel drive vehicles have two driven wheels, usually two at the front or rear wheels, while four-wheel drive vehicles have four.

The steering wheel is a wheel that changes the direction of the vehicle. The trailer wheel is neither a drive wheel nor a steering wheel. Front wheel drive vehicles usually use the rear wheels as trailer wheels.

For four-wheel vehicles, two-wheel drive refers to the transmission of torque to up to two wheels, which is called front wheel or rear wheel drive. The term 4x2 is also used to denote a total of four wheels, two of which are driven.

For vehicles with partial four-wheel drive, the term "two wheel drive" refers to the mode in which four-wheel drive is deactivated and torque is applied to only two wheels.

A tire (in us English) or a tire (in British English; see spelling differences) is a circular component that surrounds the rim of a wheel to transfer the load of the vehicle from the axle to the ground through the wheel and provide traction on the ground on which it is traveling. Most tires, such as those for cars and bicycles, are inflatable structures that also provide a flexible cushion that absorbs vibration when the tire rolls over rough features on the surface. The tire provides a footprint designed to match the weight of the vehicle to the strength of the rolling surface bearings by providing bearing pressure that does not over deform the surface.

Modern pneumatic tires are made of synthetic rubber, natural rubber, fabric and wire, as well as carbon black and other chemical compounds. They consist of tread and body. The tread provides traction and the body can hold a certain amount of compressed air. Prior to the development of rubber, the first version of the tire only had metal bands around the wooden wheels to prevent wear. Early rubber tires were solid (not pneumatic). Pneumatic tires are used in many types of vehicles, including cars, bicycles, motorcycles, buses, trucks, heavy equipment and aircraft. Metal tyres are still used in locomotives and railway vehicles, while solid rubber (or other polymer) tyres are still used in a variety of non automotive applications, such as some casters, trolleys, lawn mowers and trolleys.