Watts Linkage - Explained!

 Watts Linkage was invented by the innovative Scotsman, James Watt, who, by the time of his death in 1819, had changed history and became the most honored engineer to ever live. A variation of his linkage was designed and integrated into the rear suspension of automobiles in the early twentieth century. It was hailed as a major suspension enhancement over its successor, the Panhard rod. The Panhard rod was a long horizontal bar mounted at both the axle and the body forcing the axle to move in an arc like motion. Although the Panhard rod worked well, it introduced a lateral motion into the vertical movement of the axle. This invariably caused the host vehicle to wander somewhat during moderate and high speed maneuvering. Use of the Watts Linkage system halts this activity and ensures pure vertical motion through out the rear axle’s movement.

Ford developed its own version of Watts linkage and placed it on the updated Crown Vic in 1998. The system consists of a lateral linkage with two almost symmetrically arranged long rods mounted at each side of the chassis which run parallel to the rear axle. These bars attach to the ends of a short pivotal bar whose center is mounted to the top of the rear-end housing. As in the Panhard rod, the Watts linkage is free to pivot vertically at either end. Each horizontal member acts as a shorter Panhard rod mounted to the center vertical member providing true lateral location. This becomes most apparent as the vehicle maneuvers moderately through a corner. The tendency for body roll is diminished as the linkage helps deter lifting of the suspension from the opposing side. In turn, this helps to keep the rear tires firmly planted and the vehicle’s body weight distributed more evenly over the rear axle. Crown Vic’s most recent redesign in 2003 includes an all-new frame and a redesigned front suspension incorporating rack-and-pinion steering. All of which improves the CVPI’s crash performance and handling dynamics. With the addition of upper and lower control arms and heavy duty sway bars front and rear, the CVPI generously articulates more road confidence to its drivers than ever before.

Watts Linkage used to improve handling dynamics in Ford's Crown Victoria