Automobile suspension systems combine the principles of two key elements: pneumatic springs and shock absorbers. These not only make the ride more comfortable, but also protect the mechanical components of the vehicle. Early attempts to soften carriage travel appeared in the 16th century. The carriage body was hung like an upside-down table, suspended by leather straps from the tops of the chassis "legs." Unfortunately, this solution simply created more motion. By the mid-1600s, carriage makers had developed large C-shaped springs, but this system was little better.

Early self-powered vehicles used modified versions of the basic carriage C-springs, called leaf springs. They were strengthened by adding steel strips that tapered lengthwise from the fixed end. Their shape soon became elliptical; and they were bolted between the axles, the chassis, and body. Other springs included helical coils and straight torsion bars (coiled springs that had...