Nissan 240SX - Performance

Suspension Tuning


Shocks (AKA shock absorbers or dampers) are the most useful tool for adjusting corner entry and corner exit handling characteristics of a street car. They are easily accessible on most cars, and aftermarket shocks are usually adjustable in many ways. Shocks are necessary to dampen, or gradually reduce, the bouncing of the springs on the car. Without them, the suspension would oscillate up and down for an extended period of time after running over a bump or experiencing weight transfer.

There are two settings that determine the way a damper behaves: compression and rebound. Compression is the shock’s resistance to being pushed in, and rebound is the shocks resistance to being extended. When the car accelerates, weight is transferred to the rear, which results in the front wheels trying to lift off the ground and the rear wheels pushing harder into the ground. The front shocks are being extended while the rear shocks are getting compressed. Hence, during acceleration, the car is mainly affected by front rebound and rear compression. The opposite is true for deceleration. During deceleration, handling is affected by front compression and rear rebound.

So how do you use this information to adjust your car? First, you need to take note of what your car is doing on corner entry and exit. Shocks can be used to change the way a car handles going into a corner without noticeably affecting how it handles in the center or coming off the corner. This ability to change a specific characteristic about a car’s handling is what makes shocks so useful and important in suspension tuning. If your car is understeering on corner entry, you need to decrease front compression or increase rear rebound. If it is over steering on corner entry, increase front compression or decrease rear rebound. The rest of the adjustments are shown in the Reference Chart.