Hotchkiss Suspensions

The Hotchkiss drive was used extensively on passenger cars through the 1960s and is shown in Fig. 8.26. The system consists of a longitudinal driveshaft connected to a center differential by U-joints. The solid axle is mounted to the frame by longitudinally mounted leaf springs. Although the Hotchkiss suspension is simple, reliable, and rugged, it has been superseded by other designs for several reasons. First, as designers sought better ride qualities, the spring rates on the leaf springs dropped. This led to lateral stability difficulties because softening leaf springs requires that they be longer. Second, the longer leaf springs were susceptible to wind-up, especially as braking power and engine power began to rise. Finally, as frontwheel-drive cars became more prevalent, rear-wheel-drive cars were forced to adopt independent rear suspensions to attain similar ride and handling qualities. Nevertheless, the Hotchkiss drive is still used on many four-wheel-drive trucks and SUVs at both ends of the vehicle. One disadvantage of this suspension is that the stocky axles and differential contribute to a relatively large unsprung mass.