Barres de suspension

Suspension rods are the links that locate the axle and hold it in position relative to the chassis on a commercial vehicle. Often called torque, radius, or reaction rods, they control the movement of a heavy axle so it stays correctly placed under load, braking, and acceleration. They use bushings at their ends to allow controlled movement.

As the suspension moves and the vehicle brakes or accelerates, large forces act on the axle. Suspension rods resist those forces and keep the axle from shifting fore-and-aft or sideways, locating it precisely while allowing the spring travel the suspension needs. The bushings at each end let the rod pivot slightly while absorbing vibration.

The bushings wear, crack, or perish with age and load, allowing the axle to move more than it should. Signs include clunking or knocking from the suspension, vibration, imprecise handling, and uneven tire wear. Because a loose or broken rod lets the axle move out of position, worn rods and bushings are inspected and replaced when symptoms appear.

The correct rod depends on the vehicle model, the axle and suspension design, and the rod length and bushing fitment. Confirm the part against the vehicle specification before fitting.