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Summary
  • When a shock absorber absorbs shock, the force compresses it, sending the center shock shaft into the shock body. Shock rebound is the shock returning to its original state.
  • Shocks control the vehicle’s suspension springs by damping their movement as necessary. They do this by utilizing damping force.
  • A shock’s rebound rate is how fast it returns to its original, uncompressed state. Shock compression rates depend on how quickly the shock compresses. Aftermarket dampers, both spring-matched and coilovers, typically adjust rebound more than compression.
  • Suspension damping helps the shocks absorb the kinetic energy from bumps and potholes on the road. Dampers also keep your tires on the road surface as much as possible.

Your vehicle’s suspension system makes your ride as comfortable and stable as possible. Shock absorbers, also known as dampers, play a big part in this. Today, we’ll be tackling shock rebound and how suspension damping affects it.

Basic Shock Rebound and Compression Explained

To understand shock rebound, you need to understand shock compression. When a shock absorber absorbs shock, the force compresses it, sending the center shock shaft into the shock body. This uses up some of the kinetic energy that would’ve otherwise given you a bad bump in the cabin. The shock then converts this energy into heat, which naturally dissipates. Shock rebound is the shock returning to its original state. Rebound also occurs during acceleration and braking, to the front and rear tires respectively.

These two videos illustrate what happens when shocks totally lose their ability to dampen suspension rebounds:

What Is Damping in Suspension?

Now that you understand shock rebound and compression, let’s look at what suspension damping is. There’s a reason shock absorbers are also called dampers, after all. Shocks control how fast the vehicle’s suspension springs compress and rebound, damping their movement as necessary. They do this by utilizing damping force.

shocks on a vehicle and a diagram illustrating how shocks generate damping force
Shocks on a vehicle (left), and a diagram illustrating how shocks generate damping force (right) | Image Source: Richard McCuistian

The shocks generate damping force in the shock body by controlling the oil flow between the main piston and the base valve. As the shock shaft enters the shock body, the oil inside the body is displaced and forced to move through the base valve. The base valve controls how quickly the oil can move out of the shaft’s way. On a low damping setting, the valve allows the oil to move quickly, and on a high damping setting, the valve forces the oil to move slowly.

This process is also how shocks convert the kinetic energy from hitting a pothole into heat energy. The oil in the system gets hotter from being forced through the base valve, and that heat dissipates into the air.

Shock Rebound Rate

A shock’s rebound rate is how fast it returns to its original, uncompressed state. Low rebound damping results in a faster rebound rate, and high rebound damping results in a slower rebound rate. Generally, if your shocks have low rebound damping, you’ll notice that the ride is stiffer. High rebound damping, on the other hand, allows for a softer ride. While several factors affect ride quality, shock dampening can make a big difference.

Shock Compression Rate

As you would expect, shock compression rates depend on how quickly the shock compresses. These rates also depend on damping settings. If the shock has high compression damping, the shock compresses more slowly. Low compression damping allows the shock to compress more quickly.

Aftermarket Shocks and Suspension Damping Settings

Aftermarket dampers, both spring-matched and coilovers, typically adjust rebound more than compression. Some coilovers can adjust both, but they require more setup than dampers that only adjust rebound. Many aftermarket dampers have a knob on the damper body for easy rate adjustment.

Enthusiasts appreciate the added stiffness from increased rebound rates. Adding more rebound to rear shocks can help improve cornering on a track. On the other hand, reducing rebound will likely result in more understeering. You can increase grip when driving around corners by adjusting dampers that sit opposite to each other.

Why Damping in Suspension Matters

Suspension damping helps the shocks absorb kinetic energy from bumps and potholes on the road.

In addition to their primary purpose of absorbing shocks, dampers also control suspension spring rebound to keep your tires on the road. Although the shocks and suspension springs can return to their uncompressed state much faster, suspension damping keeps the shocks and springs from decompressing too fast. This allows for a smoother ride and keeps the tires from launching off the road from the force of the rebound.

Now that you’re more familiar with suspension damping, you can appreciate just how hard your vehicle’s shocks work to keep you comfortable and your vehicle grounded.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : Suspension
bumpers and components
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