How to Troubleshoot Suspension Behavior with Compression & Rebound Adjustment
Posted by Sean Reyes on
By including both features of compression and rebound damping response, a driver is able to precisely tune their shocks on the go in order to adapt to specific vehicle weight loadouts, or terrain features.
Compression is when the vehicle hits a bump, and the wheels/tire/axle cause the suspension and shocks to collapse into the chassis. Increasing compression damping will increase resistance to that bump, forcing the suspension to slow down during that action. Loosening up the damping will allow the suspension to more easily absorb that bump, sometimes detrimental to performance if its too soft.
Rebound is the reactionary force after that bump, and the wheels/tire/axle drop away from the chassis. When increasing rebound damping, just like compression damping, you slow the shock's response to the input. Increasing rebound damping will slow down the droop of the wheel, tire, and/or axle, making it take longer to contact the terrain. Reducing rebound damping will allow the wheels to droop/drop much faster.
For shocks that feature both compression and rebound damping adjustment (Old Man Emu BP-51, or Bilstein 8100), here are some behaviors that can be adapted according to preference.
Compression Damping
| Symptom | Remedy |
|---|---|
| Bottoms out easily on large bumps | Increase compression damping |
| Suspension feels harsh and does not soak up small bumps | Decrease compression damping |
| Shock Absorber rarely bottoms out, even off big drop offs | Decrease compression damping |
| Shock Absorber is not using all of its available travel | Decrease compression damping |
Rebound Damping
| Symptom | Remedy |
|---|---|
| Vehicle bounces and carries on repeatedly after larger bumps | Increase rebound damping |
| Suspension tops out too hard | Increase rebound damping |
| Wheels lose traction on gravel corners with corrugated surfaces (washboard) | Decrease rebound damping |
| Suspension feels harsh | Decrease rebound damping |
| Packing in repetitive bumps | Decrease rebound damping |
| Loss of traction when braking or accelerating on corrugations (washboard) | Decrease rebound damping |
If your shocks do not feature adjustment capabilities, some shocks are able to be rebuilt and serviced with these specifics in mind.
Old Man Emu - BP-51
Off-Road, Tow/Haul
$$$$
The rebound and compression adjustment is already class-leading features for OE fitted shocks. Add in the internal bypass ports of these shocks and coilovers, and you can see why these are some of our new favorite shocks. The BP51 achieves the ultimate in both comfort and off-road control through the massive amount of ride control tuning. Achieve peak hauling performance with the best shocks for hauling. Maximize stability and control for your heavy loads. Upgrade today!
Pros
- Compression adjustment to handle varying vehicle loads or tough terrain
- Rebound adjustment to pair against compression for comfort control
- Internal Bypass addresses comfort in every-day driving conditions
Cons
- Compression/Rebound Adjustment is slightly tougher to change than competitors
FOX - 2.5 Factory Series
Off-Road, Tow/Haul
$$$$
Stepping up to the Fox 2.5 Factory Race series shocks brings significant improvements in both comfort and ride control. The increased size of the 2.5” shock offers increased shock oil, lower operating pressures, and allows high speed driving on aggressive terrain while maintaining great control of the vehicle through race-level tuning.
Pros
- Huge improvement to road comfort and off-road handling in one package
- Adjustable & Reservoir options
- Serviceable, Rebuildable, Custom Tuning Available
- Excellent handling in high speed environments
Cons
- Requires servicing between 30-50k miles for optimum performance
