Shock Absorber
A mechanical or hydraulic device designed to damp shock impulses and dissipate kinetic energy, keeping tires in contact with the road.
A shock absorber (often simply called a shock) is a suspension component designed to control the rapid bouncing and rebound of the vehicle's coil springs. By converting the kinetic energy of suspension movement into thermal energy (heat) via hydraulic fluid flow, shocks damp the movement of the vehicle body.
Contrary to popular belief, shock absorbers do not support the weight of the vehicle—that is the job of the springs. Instead, the shock's primary purpose is to keep the tires firmly in contact with the road surface, ensuring traction, steering control, and braking effectiveness. Without shocks, a vehicle would continue to bounce uncontrollably after hitting a single bump.
Over time, the internal hydraulic fluid can leak out, or the internal valving can wear out, reducing damping performance. Symptoms of worn shock absorbers include excessive bouncing, body sway, nose-diving under braking, squatting during acceleration, uneven tire wear (cupping), and oily fluid leaking from the shock cylinder.
Most suspension specialists recommend inspecting shock absorbers annually or every 12,000 miles and replacing them every 50,000 to 80,000 miles to maintain safe handling and ride comfort.