Leaf Spring Suspension

The leaf spring suspension of a vehicle is the component that keeps the vehicle stiffly suspended off the ground, allowing it to absorb shock and carry passenger and cargo loads. While most of today's small passenger vehicles no longer use them, leaf springs are common on most trucks, SUVs, and heavy vehicles.

The most common type is the Hotchkiss leaf spring arrangement (see photo) with several "leafs" of metal banded together and pulled into a crescent shape.

When shock or weight on the vehicle pushes downwards, the springs flatten upwards to counteract and then spring back into their intended shape (crescent) when the weight or shock is removed.

On heavy vehicles, this can be the only suspension system in use. On lighter vehicles, the leafs are often augmented by shock absorbers.

While the layout of the springs may differ, the way they work is generally the same in all cases. Some configurations offer better ride and handling at the expense of load capacity while others focus on weight bearing at the expense of ride.

In all cases, the leafs in the spring can eventually fatigue and break down. They lose their springiness and, more often, begin to crack. Rust is always a bad thing with leaf springs, leading to a lot of side effects like squeaking, grinding, or cracking.

Leaf springs, unlike coil springs, however, are nearly always good for the life of the vehicle (or longer) under normal use. Abuse, of course, changes this.

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