Solid axle: How does it work, and where does it excel?

Solid axle
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A solid axle, or rigid or beam axle, is a type of suspension system that consists of a single rigid beam that connects two wheels on either side of the vehicle. A solid axle is an example of a dependent wheel suspension.

The beam axle is attached to the vehicle's body or chassis by a set of leaf springs or coil springs, which help to absorb shocks and vibrations caused by uneven road surfaces.


How does a solid axle work?

The solid axle serves several purposes in a vehicle. Firstly, it helps to maintain the vehicle's stability and balance, particularly during cornering and braking. The solid axle also provides better traction, as the vehicle's weight is distributed more evenly across both wheels. This feature is particularly useful in off-road vehicles or vehicles in harsh conditions.

Solid axle

Moreover, solid axles are relatively simple and durable, making them a cost-effective solution for many automotive manufacturers. They are also easy to repair and maintain, as the entire suspension system can be replaced as a single unit.

However, due to the solid axle, the car has a higher ground clearance and a higher center of gravity, which significantly worsens the car's stability, especially when driving in corners. In addition, the higher ground clearance increases the car's frontal area, significantly increasing air resistance while driving.

Advantages of a solid axle

The main advantage of a solid axle is its simple construction, lower production price, constant precise contact of the tires with the road, constant wheel track, and spatial compactness.

A solid axle also provides excellent traction, especially off-road, as the vehicle's weight is distributed evenly over both wheels. This is especially useful in rough terrain or when driving in adverse weather conditions.

Its simple design makes it a cost-effective solution for many car manufacturers. A solid axle is also easy to repair and less expensive to maintain, as the entire suspension system can be replaced as a single unit.

Disadvantages of a solid axle

Among the disadvantages of a solid axle we can include impaired driving characteristics and worse car controllability because the wheels cannot move independently after hitting an uneven surface.

The higher unsprung weight of solid axles results in higher fuel consumption and worse ability to absorb road irregularities, which does not benefit driving comfort or driving characteristics. Because of these shortcomings, the solid axle is replaced by a multi-link suspension.

Why is the solid font axle used less nowadays?

From the point of view of driving characteristics and safety, the steered wheels must constantly be in contact with the road. Unlike independent wheel suspension, dependent wheel suspension using a solid axle is worse in many cases, so the front solid axle is not used much today.

Video showing the function of a rigid axle