What is a Watts Link, and How Does It Work?

A watts linkage is a part of the rear suspension. It's used to locate the rear axle laterally underneath the car, while allowing the body of the car to travel vertically. A watts link attaches to the rear axle with a pivot point, then its arms bolt to the body of the car. As the body of the car moves up and down, the pivot point will move up and down, traveling in a line. Since the pivot point is traveling in a line, it keeps the axle located directly under the car.

A panhard bar is a great upgrade for 79-04 Mustangs, and the 05-14 Mustangs come with them stock. They are also used to locate the rear end laterally underneath the car. The panhard bar is a cheap and simple way of locating the axle, but it comes with some minor flaws. Because it's a solid bar, as the body of the car moves up and down, the panhard bar will push or pull the axle one way or the other. To understand the motion of a rear end with a panhard bar, picture a clocks pendulum. The movement is not as dramatic as a clocks pendulum, but you still want to keep the axle as centered as possible. You can see in the illustration below, the car's body is able to swing over the rear axle. By ditching the panhard bar set-up, you can keep the rear end more firmly planted during suspension travel.

A watts linkage is connected to the chassis of a car by two equal length horizontal rods. These rods are then connected to another vertical section which is bolted to the rear end. This vertical section is a pivot point which allows the axle to move in an up and down motion, following a line. As the body of the vehicle raises and lowers, the arms will twist the pivot point, which keeps the rear centered under the body of the car. Since the axle is only traveling up and down, there is no lateral motion of the rear end. Without the rear axle swinging like a pendulum, the car is much more stable and sure-footed, especially over bumps. The diagram below shows how as the body of the car raises, the point on the axle will pivot as the arms move, allowing the axle to stay centered under the body of the car.

• A watts link keeps your Mustang’s rear axle centered under the car during suspension travel and cornering
• A watts link is an upgraded design to a panhard bar. Panhard bars can’t keep the rear axle centered when the suspension moves up and down
• 79-04 Mustangs don’t come with a panhard bar stock, but 05-14 Mustangs do
• A watts link utilizes extra rods as pivot points to eliminate the inherent weakness in a panhard bar
• A watts link works well in a variety of Mustang setups like drag or track builds

A watts link is a must have for a serious corner carver or handling enthusiast. Keeping lateral axle movement to minimum will help prevent the rear end from having a squirelly sensation and will give the driver more control over the car. A watts link will even work well for drag racers, keeping the car from swaying as you shift your way down the track. While it is more expensive than a panhard bar, its well worth the extra money for the increased stability.