The most common types of lateral axle locators; Panhard bar, Watts link, A-arm, and Track bar are used to locate a live axle to minimize side-to-side movement that can cause handling instability. Although the purpose of these devices is to improve chassis stability they are very different from an anti-roll bar.

Anti-roll bars help minimize chassis/body roll by transferring weight from one side of the chassis to the opposite side while cornering. However rather than being a rigid and inflexible device, an anti-roll bar is a type of torsion spring that requires flexibility to function.

Whatever the design, a lateral axle locator and the brackets that secure it need to be made from strong, rigid material. As these devices connect a live axle to the chassis they require a bushing on each end to allow for movement and to minimize transfer of road vibration.

As the Panhard bar and Watts link rotate around fixed mounting points on either the axle or chassis, urethane bushings are usually suitable for this purpose.

A lateral axle locator will stop a dropped front axle from rocking side-to-side on the transverse spring shackles..."

For optimum function a Panhard bar should be as long as possible and mounted parallel to the axle and the road surface. The longer the bar the more shallow the arc will be that the axle travels through during suspension movement.

   • Click here to see panhard function & arc of travel

A more sophisticated design, the Watts link uses two links and a bell-crank to completely eliminate any arc as the axle travels up and down.

   • Click here to see Watts link function & vertical travel

A-arm lateral axle locators are usually mounted in the lower link position relative to the axle. The two front mounting points that connect to the chassis can usually use urethane bushings. However, the opposite end of the A-arm that connects to the center of the axle requires very strong brackets and a rod end, as this single point carries all of the load and must allow the axle to rotate around the chassis centerline without binding. As a result, spherical rods ends are usually mandatory. Like a Watts link, an A-arm allows the axle to move vertically rather than in an arc during suspension travel.

   • Click here to see A-arm design

A variation of the A-arm is when a four link rear suspension features triangulated links, which eliminate the need for any additional type of lateral axle locator. In this instance the triangulating links are usually the top arms rather than the lower ones.

   • Click here to see triangulated four-link design

Lastly is the Track bar, which is commonly used in drag racing with parallel link four bar rear suspensions. Track bars connect diagonally from the lower front four-link to the lower rear four link. They are only really suitable for quarter mile racing where the car predominantly runs in a straight line on a smooth surface. Around corners and over bumps a track bar will bind very easily even when fitted with rod ends, and are prone to failure as a more

   • Click here to see track bar design

TECH PROFILE: Why there's no 'universal' suspension bushing



Read more about: