Editing Coil spring (section)

== Applications ==
[[file:1969 AMC SCRambler valv.jpg|thumb|Coil spring in valvetrain]]

Coil springs have many applications; notable ones include:

* [[Buckling spring]]s in [[computer keyboard]]s
* [[Mattress coil]]s in [[innerspring mattress]]es
* [[Upholstery coil springs]] in [[upholstery]]

Coil springs are commonly used in [[Car suspension|vehicle suspension]]. These springs are compression springs and can differ greatly in strength and in size depending on application. A coil spring suspension can be stiff to soft depending on the vehicle it is used on. Coil spring can be either mounted with a shock absorber or mounted separately. Coil springs in trucks allow them to ride smoothly when unloaded and once loaded the spring compresses and becomes stiff. This allows the vehicle to bounce less when loaded. Coil spring suspension is also used in high performance cars so that the car can absorb bumps and have low body roll. In off-road vehicles they are used because of their range of travel they allow at the wheel.

Coil springs used in the engine are compression springs and play an important role in closing the valves that feed air and let exhaust gasses out of the combustion chamber. The spring is attached to a rocker that is connected to the valve.

Tension and extension coil springs of a given material, wire diameter and coil diameter exert the same force when fully loaded; increased number of coils merely (linearly) increases free length and compressed/extended length.