四轮驱动
Any four-wheel-drive (4WD/AWD) vehicle needs suspension for both the front wheels and rear wheels, but in two-wheel-drive vehicles there could be a very different configuration. For front-wheel drive cars, rear suspension has few constraints, and a variety of beam axles and independent suspensions are used. For rear-wheel drive cars, rear suspension has many constraints, and the development of the superior, but more expensive independent suspension layout has been difficult. Four-wheel drive often has suspensions that are similar for both the front and rear wheels.