Automotive shock absorbers are primarily designed to suppress oscillations that occur when suspension springs rebound after absorbing shocks, as well as to dampen impacts from the road surface. When driving over uneven terrain, although the suspension springs filter out road vibrations, the springs themselves tend to oscillate; the shock absorber serves to control this spring bounce.
If shock absorbers are too soft, the vehicle body will bounce up and down; conversely, if they are too stiff, they create excessive resistance that hinders the proper functioning of the springs. When modifying a suspension system, stiff shock absorbers must be paired with stiff springs-and since spring stiffness is closely linked to vehicle weight, heavier vehicles typically utilize stiffer shock absorber components. The device connected to the engine crankshaft is designed to counteract torsional vibration-a phenomenon where the crankshaft twists due to the impact forces generated by cylinder ignition.