Axles are an integral component of most practical wheeled vehicles. In a live-axle suspension system, the axles serve to transmit driving torque to the wheel, as well as to maintain the position of the wheels relative to each other and to the vehicle body. The axles in this system must also bear the weight of the vehicle plus any cargo.
A non-driving axle, such as the front beam axle in heavy duty trucks and some 2-wheel drive light trucks and vans, will have no shaft, and serves only as a suspension and steering component. Conversely, many front wheel drive cars have a solid rear beam axle.
In other types of suspension systems, the axles serve only to transmit driving torque to the wheels; the position and angle of the wheel hubs is an independent function of the suspension system. This is typical of the independent suspension found on most newer cars and SUV’s, and on the front of many light trucks. These systems still have a differential, but it will not have attached axle housing tubes. It may be attached to the vehicle frame or body, or integral in a transaxle.
The axle shafts (usually constant velocity type) then transmit driving torque to the wheels. Like a full floating axle system, the drive shafts in a front wheel drive independent suspension system do not support any vehicle weight.