Shocks (or "Dampers")
This page of the guide is the least fully-developed, and should be regarded as “draft” status. Check back, as I plan to improve the content, especially for use with the Next Gen Cup car.
The final stage of the setup process is fine-tuning the chassis' behavior using the shocks. This step is essentially optional, but it will make a great setup perfect! In fact, the Next Gen NASCAR Cup Car will be tuned almost exclusively with shocks, so this content will soon be updated to address these setups.
Shocks (also known as “dampers”) control weight transfer during transient maneuvers in the car. In terms of fine-tuning a setup, the depth of understanding here could require more study, track testing, and effort than the time gains to be had here. In other words, you may go beyond the point of diminishing returns by putting too much effort into the shocks; but, if you’re looking to squeeze a tiny bit more time out of your laps while also making the car more comfortable and natural to drive, shock adjustments really are the icing on the setup cake.
So what kind of driving will shock adjustments help with? Transient maneuvers:
Transient maneuvers: Maneuvers which transfer weight between the wheels at the four corners (acceleration, braking, and cornering; and all possible combinations of these).
Steady state: No changes in speed, direction or corner weight distribution; equilibrium.
How much weight ultimately gets transferred is determined by the spring rates; but shocks affect how rapidly the weight transfer takes place. Setting up your shocks correctly will help keep your car under control when stopping and accelerating, especially while turning.
Shocks usually have two adjustments that can be made: Compression stiffness, and rebound stiffness. Compression stiffness refers to how stiff the shocks are when they’re pushed down. Rebound stiffness refers to how stiff the shocks are when they pop back up. The Next Gen Cup car (and some road cars) double this complexity by allowing for “low speed” and “high speed” compression and rebound stiffness.
A Stepping Off Point
Because the shocks generally address differences in the way different racers drive, changes to the shocks should come last in the setup process, only after you’ve achieved a neutral setup by other means (i.e. ride heights, springs, alignment and tires).
To start out, use a 50/50 shock setting at 1/2 the shock’s maximum value (e.g., if your range is 0-32, use a setting of 16 for both compression and rebound stiffness for all shock settings). Then, because shocks have the exact same effect on a car’s handling as springs do (to a lesser degree), make adjustments per the advice in the spring stiffness guide from there.
Fine-Tuning the Corner Entry and Exit with Shocks
Shocks mainly affect the transient handling of the chassis (meaning, when you apply or lift either the brake or the throttle). You can also address small differences in the track’s handling due to weather (temperature) by loosening or tightening the handling through the shocks.
The following tables describe the effects of stiffer (increased) bump and rebound stiffness. To achieve the opposite effect, just reverse the logic (e.g., if it says “tighten entry”, and you want to “loosen entry,” simply soften the shock instead of stiffening it).
If you change bump or rebound stiffness equally at either the front or rear axle, you can make general behavioral changes to the chassis according to the tables below.
|Adjustment (Both Sides)|
|Bump||tighten entry (braking and turn-in)||loosen entry (braking and turn-in)|
|Rebound||tighten exit (acceleration)||loosen exit (acceleration)|
|Adjustment (Both Sides)|
|Bump||tighten exit (acceleration)||loosen exit (Acceleration)|
|Rebound||tighten entry (braking and turn-in)||loosen entry (braking and turn-in)|
Split Valved Shocks
A shock using a different stiffness between the compression (bump) stiffness, and the rebound stiffness is called a “split valve shock.” Asymmetrical changes utilizing split valve shocks provide literally limitless possibilities to get the final nagging bugs out of your setup’s feel.
Asymmetrical Changes by Location
The following tables show the possible effects of making split valve shock adjustments to individual shock locations. These changes usually work best in the right combinations, shown in the “Changes by Combination” table which follows. Nonetheless, this table is useful for reference when examining your shock configurations to help point you in the right direction when working on your setup.
|Bump||tighten car on corner entry||loosen car on corner entry|
|Rebound||tighten car in middle on-throttle; tighten car through corner exit||loosen car in middle on-throttle; loosen car through corner exit|
|Bump||tighten car on corner entry; tighten car in middle off-throttle||loosen car on corner entry; loosen car in middle off-throttle|
|Rebound||loosen car in middle on-throttle||tighten car in middle on-throttle|
|Bump||loosen car on corner entry; loosen car in middle on-throttle; loosen car in middle off-throttle; loosen car through corner exit||tighten car on corner entry; tighten car in middle on-throttle; tighten car in middle off-throttle; tighten car through corner exit|
|Rebound||loosen car in middle on-throttle; loosen car through corner exit||tighten car in middle on-throttle; tighten car through corner exit|
|Bump||loosen car on corner entry; loosen car in middle on-throttle||tighten car on corner entry; tighten car in middle on-throttle|