Most amateur mechanics have likely heard the suspension is a very important part of their vehicle. However, fewer would be able to explain what exactly the suspension does or why it's so critical. Understanding your car's suspension will allow you to fix a number of issues associated with how a car handles, and generally make your ride smoother.
The first thing to keep in mind is that the suspension is not a singular part in the way a radiator or engine is. The suspension refers to the entire system that keeps the car moving along smoothly. The engine generates power for a vehicle, but all of that power is ultimately useless if the driver isn't able to control the car. This is where the suspension comes into play.
Suspensions would not be necessary if the roads we drove on were perfect. A car driving on a completely smooth surface with no imperfections wouldn't really need a suspension system in place. However, don't get the idea that a suspension is only necessary for those drivers who like to go off-roading. Even main highways have little grooves, bumps and flaws that ultimately affect a vehicle traveling over it at a high rate of speed.
Essentially, your car is hitting bumps, small divots and a variety of other things on the road all the time. The reason you don't really notice has to do with the suspension, which is designed to absorb the jolts that these surface imperfections send through the vehicle.
The fancy term for this is "road isolation," and it's one of the three jobs assigned to the suspension. Different vehicles have different abilities when it comes to road isolation. On some low-end models, your suspension is likely just about good enough to avoid sustaining damage to the car. High-end luxury models pride themselves on delivering smooth rides through expensive shock absorbers and springs that ensure the driver doesn't feel a thing.
The springs are also responsible for road handling, and that's the second aspect of the suspension. Usually, this is in direct opposition to road isolation, and it depends on how tight the springs are. Loose springs absorb shocks better, but make the car a bit less responsive when it comes to handling. Meanwhile, drivers in sports cars will likely feel all of those little bumps in the road - but they'll have much better handling when it comes time to turn the wheel.
Finally, the suspension is also responsible for handling a vehicle's cornering capabilities. This is essentially just a weight distribution system.related to how the car is balanced. Whenever a vehicle corners, even slightly, one part of the car will rise slightly higher than the other. The suspension shifts the weight to the lower side of the car in order to prevent the vehicle from going out of control when this happens.
Drivers may also have heard of the term "independent suspension." This really just refers to how the car's axles are set up. Older vehicles used a dependent suspension that had both wheels connected on one axle, providing stability. Today, most automakers see the value in independent suspensions that allow the wheels to move freely, as this results in better handling for the vehicle. Still, some larger cars that don't need to handle as well as a sedan or coupe rely on dependent suspensions.