A modern suspension system is used as a connection point between the towing axle and the frame.The suspension system keeps the tires in contact with the road while driving on uneven roads, absorbing and cushioning the shock effect that can result from an imperfect road surface.

Leaf-Spring Suspension Systems

On the uniaxial suspension system, the plate spring is connected to the front hanger, which is welded to the trailer frame.The rear of the plate spring is bolted to the spring hook.The rear hanger connects the hook ring to the frame.The plate spring design has an arch, the profile of which is part of the specific function of the spring design.When the plate spring is placed under load, the spring flattens out slightly and stretches.The spring hook allows the spring to move backwards and upwards when compressed.

The tandem shaft and triaxial suspension systems are slightly more complex and use a component called a balancer to distribute weight between the shafts during ride on jolts and tilts.If no equalizer is used on the tandem system, an axle may be forced to support too much weight.In a worst-case scenario, the front axle of the tandem suspension can be jarred across without an equalizer, which can cause the rear axle wheel/tire to lift off the ground.In an instant, the front axle will support the trailer's full weight.

The equalizer is attached to a central hanger welded to the trailer frame.Hook-and-loop chains and bolts connect the plate spring to the balancer and allow the spring to lengthen during compression.Most trailers and the fifth wheel are equipped with triangular equalizers made of solid steel.