Shocks and struts are two very similar parts that serve similar purposes. Both shocks and struts absorb the bumps in the road and keep the tires of the vehicle on the ground, creating a smoother ride. A car without shocks or struts would bounce all over the road and be nearly undrivable, as well as dangerous.
Shocks are the oldest form of suspension still used today. They are similar to pistons - tubes filled with hydraulic fluid or gas with a rod inside, connected to the chassis of the car. When the car rolls over a bump, the piston forces the air or fluid through the tube. Only a limited amount of fluid or air can move at a time, which, combined with springs, resists vehicle movement and prevents the chassis of the car from bouncing rapidly.
Struts are the evolved version of shocks. They are a component that combines the spring with a shock absorber to reduce production costs and simplify construction. Struts also serve as pivots for the steering rack and are part of the wheel’s upper control arm. They are a very integral part of the car’s suspension.
Shock and Strut Benefits
Shocks are cheaper to replace than struts, but they only reduce the bounce of the vehicle, and do not provide extra support for the wheel like struts do. Struts are more expensive to replace, but combine shocks and springs to make repairs and manufacturing easier. If your car came with shocks, you can only use shocks. You cannot upgrade a car that uses only shocks to using struts.