Coil Spring
A spiral-wound metal spring that supports the vehicle weight and compresses to absorb road shocks and bumps.
A coil spring is a heavy-duty, spiral-wound steel bar that forms the core suspension component in most modern passenger cars, SUVs, and light trucks. Positioned between the vehicle frame and the control arms or integrated around a strut (as a MacPherson strut assembly), the coil spring supports the weight of the vehicle and keeps it at the correct ride height.
When the vehicle hits a bump, the coil spring compresses to absorb the energy of the impact, preventing it from transferring directly to the passenger cabin. It then rebounds to push the wheel back down, maintaining constant tire contact with the road surface for steering and braking traction.
Although coil springs are highly durable, they can sag over time, rust, or crack due to fatigue. Worn coil springs lead to a lower ride height, bottoming out over bumps, increased body roll during cornering, and uneven tire wear. They should always be replaced in pairs to ensure balanced suspension height and handling.