Valvoline.com

Shock Tale

Worn shocks tell a suspenseful story

It's easy to forget about what's going on as your car or truck hurtles down the road over potholes, railroad tracks and other road surface irregularities. While you wile away the commute listening to the radio, talking on the phone or enjoying the scenery, the suspension underneath the seat of your pants isolates you from the rough surfaces of the road.

Spring Time

The suspension also allows for control of the vehicle as it travels along at breakneck speeds. The two main components that work together in the suspension are the springs and shock absorbers. The springs suspend the vehicle on the suspension and allow the car, truck, van, or SUV to roll over the bumps with a spring, instead of a jolt. Coil and leaf springs are a few conventional spring types. Some springs are actually bars that use twist, or torsion, to allow for suspension travel. Whether torsion bar or coil spring, they all work the same way.

Self-Absorbed

The spring takes up the energy of bumps and the weight of the vehicle, so the seat of your pants doesn't. The problem comes when that same energy tries to get back out of the spring, and causes the vehicle to bounce. This is where the shock absorber comes into play, and the main reason it is a crucial part of safe vehicle operation. A tire cannot keep contact with the road if it is bouncing up and down off its surface. Cornering, braking, and vehicle control are all greatly affected by the shock absorber.

Safety Valve

While springs generally last for the life of the vehicle, shock absorbers do not. Like brake pads, tires, and clutches, shock absorbers are wear items. Since the shock absorbers work with the spring to keep the wheels and the vehicle itself from bouncing all over the road as you drive, they're at work every time you turn the ignition key. Shock absorbers perform this ride-calming act by being the buffers between one end of each spring, and the chassis of the vehicle. Inside the shock absorber are a series of pistons and valves surrounded by oil. The energy of the spring trying to bounce is absorbed by the amount of energy it takes to move the oil through the valves as the piston travels inside each shock absorber.

Natural Reaction

Imagine how difficult it would be to operate a bicycle tire hand pump if it was filled with thick oil instead of air, and you get an idea of how a shock absorber works. The shock absorber dampens the blow of bumps, and the reaction of that same energy trying to get back out of the spring. Inspecting your shock absorbers is important not only to maintain a smooth ride, but also to maintain control on the road. Shock absorbers wear out slowly, so the wear may not be noticeable as you become accustomed to the wallowing ride. Let the odometer be your guide. Inspect shocks at 25K, according to your driving conditions, or manufacturer's recommendations. While the following steps are good general tests, if there is any question as to the condition of your shock absorbers a safe bet is to get them tested or replaced. It's always a good idea to err on the safe side when it comes to vehicle handling.