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Absorbing the Road, Delivering the Speed
Precision in Motion
In racing, speed isn’t just about horsepower, it's about control. Dampers are the unsung heroes of suspension, quietly dictating how your car dances with the track. Get them wrong, and every bump, curb, and weight shift becomes a fight. Get them right, and you unlock a chassis that flows through corners, devours curbs, and keeps all four tires glued to the asphalt. This is where milliseconds are won: welcome to the fine art of damping.
DAMPERS
Dampers are related to the shock absorber found within the suspension of the car. Many road and race cars use coilover suspension, the spring sorrounds the damper body. As with all cars having the correct damper settings can make the car handle much more aggressive or stable depending on your preference. So getting these values correct is crucial to building a setup.
This guide will discuss 4-way adjustable damping, broken up into rebound and bump in both slow and fast states. Low-speed damping impacts chassis movements from driver inputs (braking, steering, throttle). High-speed damping affects response to bumps, curbs, and surface irregularities. What dampers do is help dissipate any vertical movement in the suspension and keep spring travel under control. This has a knock-on effect on helping keep the wheels on all 4 corners of the car in contact with the ground.
Bump controls compression and rebound controls extension of the damper, they don’t directly control load levels received, but instead control the speed of the load changes and ensure the suspension reacts in a stable manner.
Tracks that have more bumps or quick transitions and changes of direction require more emphasis on dampers. The quicker the suspension has to react and move to the circuit’s demands, the more effect the dampers have.
Because curb handling and bump behavior is very important, adjusting the damper tune is critical to allow your car to take them effectively. However, going too far one way or another can lead to an unpredictable car.
It is important to remember, dampers don’t generate grip, they preserve it. Their role is to control how quickly load shifts between the tires, keeping the contact patches more consistent. Well tuned dampers help the suspension maintain the grip the tires and track surface can already provide, but they cannot create extra grip beyond what’s physically available.
High-Speed vs. Low-Speed Damping
Low-Speed Settings:
Control the slower, more gradual movements of the suspension, like during braking, cornering, and throttle application.
High-Speed Settings:
Control the rapid movements from impacts like potholes or curbs, keeping the chassis stable over rough surfaces.
You can watch this video to learn how to set, adjust, and tune coilover damper settings:
Bump & Rebound
There are a few basic features of a damper that need to be understood to fully understand how to create the correct setup.
It’s all about understanding how long weight stays on a given axle and how weight transfer directly impacts front vs. rear grip balance.
Bump (Compression)
Governs how quickly the suspension compresses.
Stiffening bump damping slows compression, increasing the rate of load transfer.
Too much front bump: Can cause understeer on corner entry because the front tires aren’t loaded enough to bite.
Too little front bump: Can cause excessive dive under braking, overloading the front tires, causing instability or oversteer on turn-in.
Too much rear bump: May cause oversteer when accelerating out of slow corners, as the rear tires can’t load up smoothly.
The lower the value the faster the suspension will compress.
Rebound (Extension)
Governs how quickly the suspension extends back to or returns to its normal position.
Stiffening rebound slows extension, reducing weight transfer.
Too much front rebound: Can cause understeer mid-corner as the front stays compressed too long
Too little front rebound: Can cause oversteer on corner entry as the front extends too quickly
Too much rear rebound: Can cause understeer on corner exit as the rear stays compressed too long
Too little rear rebound: Can cause oversteer on exit as the rear extends too quickly
A lower value will allow the suspension to return to its original state faster
IMPORTANT: The extension should be greater than the compression!
Fast Bump (Compression)
This differs from the base bump as it controls the rate of compression for quick short hits to the suspension.
The lower the value the faster the suspension will compress over quick short compression.
Too much front fast bump: Front tires may skip across the curb surface, reducing grip and causing entry understeer.
Too little front fast bump: Front suspension compresses too easily, risking bottoming out on the curb.
Too much rear fast bump: Rear axle “hops” over curbs, breaking traction and risking snap oversteer on corner exit.
Too little rear fast bump: Rear suspension squats excessively on curbs, risking contact with bump stops.
Fast Rebound (Extension)
This differs from the base rebound as it controls the rate of extension for quick short hits to the suspension.
A lower value will allow the suspension to return to its original state faster after a quick short compression.
Too much front fast rebound: Can cause understeer immediately after curb exit as the front “hangs” in the air.
Too little front fast rebound: Can unsettle the car under braking zones that follow curbs.
Too much rear fast rebound: Rear wheels can’t drop quickly after curb exit, losing traction and causing oversteer on throttle.
Too little rear fast rebound: Rear bounces after curb exit, breaking traction on acceleration.
IMPORTANT: The extension should be greater than the compression!
Corner Phases and Slow Damper Effects
Corner Entry:
This phase involves braking and steering, which transfers weight to the front and outside tires.
Too much front bump: Can make weight transfer too abrupt, leading to understeer as the front tires can’t generate enough grip.
Too little front speed bump: Allows excessive dive, overloading the front tires and potentially causing instability or oversteer on turn‑in.
Too much rear rebound: Rear extends slowly, can help with rotation but may cause oversteer.
Too little rear rebound: Rear extends too quickly, shifting weight forward abruptly, can cause oversteer on entry as the rear unloads.
Mid-Corner:
The car is at its maximum rotation, with steady weight distribution.
Too much front rebound: Keeps the front compressed, maintaining front grip but unloading the rear, can cause oversteer mid‑corner.
Too little front rebound: Allows the front to rise too quickly, unloading the front tires, can cause understeer mid‑corner.
Too much rear rebound: Keeps the rear compressed, maintaining rear grip but unloading the front, can cause understeer mid‑corner.
Too little rear rebound: Allows the rear to rise too quickly, unloading the rear tires, can cause oversteer mid‑corner.
Corner Exit:
Weight transfers to the rear as the car straightens and accelerates.
Too much front rebound: Transfers weight to the rear too quickly, unloading the front, can cause understeer on exit.
Too little front rebound: Keeps the front lower for longer, improving front grip but may reduce rear traction, can cause oversteer if rear is light.
Too much rear rebound: Keeps weight on the rear longer, improving traction but possibly causing understeer if the front stays unloaded.
Too little rear rebound: Allows the rear to extend too quickly, unloading the rear tires, can cause oversteer on exit.
Dampers & Spring Rates
Dampers and springs work as a team. One stores and releases energy, the other controls how that energy is released. The spring rate determines how much the suspension moves under load, while the damper controls the speed of that movement.
Damper settings should always be matched to spring rates:
Stiffer Springs: Compress and extend more quickly under load, so they often require more damping to keep motion in check and prevent the car from feeling skittish.
Softer Springs: Move more slowly and absorb more energy on their own, so they need less damping to avoid overdamping, which can make the suspension feel harsh and reduce grip.
If damping is mismatched to the spring:
Too much damping for the spring rate: Suspension feels rigid, tires skip over bumps, and grip suffers.
Too little damping for the spring rate: Suspension oscillates, feels “floaty,” and takes too long to settle after weight transfer.
The goal is to balance spring stiffness and damper control so the suspension moves just enough to keep the tires in consistent contact with the track, without excessive bounce or harshness.
Slow Damper Adjustment
Slow dampers control how the suspension reacts to gradual inputs, like steering, throttle, and brake pressure. They shape the car’s attitude through corners, affect pitch and roll, and determine how weight shifts across the chassis.
Front Bump
Adjustment: Increase
Effect: More Understeer
Behavior: Stiffens front compression, reducing front grip during turn-in. The car resists rotating.
Front Bump
Adjustment: Decrease
Effect: More Oversteer
Behavior: Softer compression allows more front grip, helping the car rotate more easily.
Front Rebound
Adjustment: Increase
Effect: More Oversteer
Behavior: Slows front suspension return, keeping weight on the rear longer. Promotes rear rotation.
Front Rebound
Adjustment: Decrease
Effect: More Understeer
Behavior: Faster rebound shifts weight forward sooner, reducing rear rotation and tightening the car.
Rear Bump
Adjustment: Increase
Effect: More Oversteer
Behavior: Stiff rear compression reduces rear grip during weight transfer, causing the rear to step out.
Rear Bump
Adjustment: Decrease
Effect: More Understeer
Behavior: Softer compression increases rear grip, stabilizing the rear and reducing rotation.
Rear Rebound
Adjustment: Increase
Effect: More Understeer
Behavior: Slows rear suspension return, keeping weight on the front longer. Reduces rear rotation.
Rear Rebound
Adjustment: Decrease
Effect: More Oversteer
Behavior: Faster rebound shifts weight rearward sooner, loosening the rear and increasing rotation.
Slow Damper Tuning Tips
Corner entry balance:
Use front slow bump and rebound to control dive and rotation. Softer bump = better grip; stiffer rebound = more rotation.
Corner exit traction:
Rear slow bump and rebound affect how the car plants itself under throttle. Softer bump = more grip; stiffer rebound = calmer rear.
Body control:
If the car feels too floaty or rolls excessively, increase slow bump. If it feels too stiff or snappy, decrease it slightly.
Driver style matters:
Aggressive drivers may prefer softer slow bump for responsiveness; smoother drivers might benefit from firmer settings for stability.
Fast Damper Adjustment
Fast dampers control high-speed suspension movement, which is exactly what happens when you hit curbs, rumble strips, or sudden bumps. The goal is to balance compliance (absorbing the impact) with control (keeping the car composed).
Front Fast Bump
Adjustment: Increase
Compliance: Less compliant
Behavior: Makes the front stiffer over curbs, less absorption, more jarring impact. Can cause the front tires to skip or lose grip mid-turn.
Front Fast Bump
Adjustment: Decrease
Compliance: More compliant
Behavior: Softer front absorbs curbs better, keeping tires planted and improving turn-in stability. Ideal for aggressive curb use.
Front Fast Rebound
Adjustment: Increase
Compliance: Less compliant
Behavior: Slows how quickly the front recovers after hitting a curb—keeps weight rearward longer, helping rotation but may feel sluggish.
Front Fast Rebound
Adjustment: Decrease
Compliance: More compliant
Behavior: Faster recovery after curb impact—weight shifts forward quickly, tightening the car but risking front-end bounce.
Rear Fast Bump
Adjustment: Increase
Compliance: Less compliant
Behavior: Rear becomes harsh over curbs—can destabilize the car on throttle exits or cause snap oversteer if the rear skips.
Rear Fast Bump
Adjustment: Decrease
Compliance: More compliant
Behavior: Softer rear absorbs curb hits better, keeping traction and reducing rotation. Helps settle the car on corner exit.
Rear Fast Rebound
Adjustment: Increase
Compliance: Less compliant
Behavior: Slows rear recovery after curb impact—keeps weight forward longer, calming the rear but may feel lazy on throttle.
Rear Fast Rebound
Adjustment: Decrease
Compliance: More compliant
Behavior: Quicker rear rebound after curbs—can cause rear-end lift or twitchiness if too soft, but improves rotation if controlled.
Fast Damper Tuning Tips
If attacking curbs aggressively:
Soften fast bump settings to let the suspension absorb the hit without upsetting the chassis.
If the car feels floaty or unstable after curbs:
Increase fast rebound slightly to slow the recovery and keep the car composed.
If curbs cause snap oversteer on exit:
Soften rear fast bump and/or increase rear fast rebound to stabilize the rear.
If curbs cause front-end push or bounce:
Soften front fast bump and slightly decrease front fast rebound for better grip and quicker recovery.
Curb Combat
Front Fast Bump
Too Much (Too Stiff)
Behavior: Reduced curb compliance causes understeer on entry and unsettled steering in chicanes
Symptom: Suspension resists compression over curbs
Cause: Front Fast Bump damping is too stiff (Too Much)
Effect: Front skips or bounces over curbs, steering becomes delayed
Solution: Soften Front Fast Bump to allow the front tires to stay in contact with the road when hitting curbs
Too Little (Too Soft)
Behavior: Front instability under braking and inconsistent turn-in due to chassis pitch
Symptom: Suspension compresses too easily over curbs
Cause: Front Fast Bump damping is too soft (Too Little)
Effect: Excessive dive into curbs; may bottom out or feel unstable
Solution: Stiffen Front Fast Bump slightly to prevent bottoming and maintain chassis control when riding curbs
Front Fast Rebound
Too Much (Too Stiff)
Behavior: Hesitant steering after curb contact and slower rotation into corners
Symptom: Suspension extends too slowly after curb impact
Cause: Front Fast Rebound damping is too stiff (Too Much)
Effect: Front takes too long to recover after hitting curbs; steering remains vague
Solution: Soften Front Fast Rebound to allow quicker recovery and sharper turn-in after curb contact
Too Little (Too Soft)
Behavior: Nervous steering and unpredictable front grip on bumpy entries
Symptom: Suspension extends too quickly after curb impact
Cause: Front Fast Rebound damping is too soft (Too Little)
Effect: Front may bounce or oscillate after curbs; unstable steering
Solution: Stiffen Front Fast Rebound slightly to control front-end rebound and stabilize steering over curbs
Rear Fast Bump
Too Much (Too Stiff)
Behavior: Snap oversteer and poor throttle stability when exiting corners over curbs
Symptom: Suspension resists compression over curbs
Cause: Rear Fast Bump damping is too stiff (Too Much)
Effect: Rear loses traction when hitting curbs
Solution: Soften Rear Fast Bump to keep rear tires planted over curbs and improve traction on exit
Too Little (Too Soft)
Behavior: Rear-end float during throttle application and delayed rotation response
Symptom: Suspension compresses too easily over curbs
Cause: Rear Fast Bump damping is too soft (Too Little)
Effect: Rear squats excessively over curbs; may feel unstable under acceleration
Solution: Stiffen Rear Fast Bump slightly to reduce squat and maintain rear-end control over curb strikes
Rear Fast Rebound
Too Much (Too Stiff)
Behavior: Rear grip delay after curb hit and unstable throttle response
Symptom: Suspension extends too slowly after curb impact
Cause: Rear Fast Rebound damping is too stiff (Too Much)
Effect: Rear remains unloaded after curbs; poor traction on exit
Solution: Soften Rear Fast Rebound to help rear tires replant faster and improve stability after curb hits
Too Little (Too Soft)
Behavior: Rear-end oscillation and inconsistent grip over curb transitions
Symptom: Suspension extends too quickly after curb impact
Cause: Rear Fast Rebound damping is too soft (Too Little)
Effect: Rear bounces or feels unstable after curbs; traction becomes unpredictable
Solution: Stiffen Rear Fast Rebound slightly to control rear-end recovery and maintain balance
Cornering : Balancing Oversteer and Understeer
Oversteer
Turn-In Oversteer
Cause: Front slow bump too soft
Effect: Car feels unstable on entry, Rear end rotates too quickly
Solution:
Increase front slow bump to reduce pitch
Lower rear rebound to help rear tires settle faster
Consider softening rear anti-roll bar to reduce lateral load
Corner Apex Oversteer
Cause: Rear rebound too high
Effect: Car snaps or slides mid-corner, Sudden rotation at apex
Solution:
Lower rear rebound to allow quicker tire contact
Increase front rebound slightly to stabilize front-end grip
Differential settings, too much preload can cause snap rotation
Corner Exit Oversteer
Cause: Rear slow bump too stiff
Effect: Hard to apply power smoothly, Rear steps out under throttle
Solution:
Reduce rear slow bump to soften initial compression
Increase front rebound to help front tires bite earlier
Consider softening rear springs or adjusting throttle mapping
Understeer
Turn-In Understeer
Cause: Front slow bump too stiff
Effect: Car resists turning in, Front tires scrub across the surface
Solution:
Soften front slow bump to allow better weight transfer
Lower front rebound to slow tire settling and reduce bite
Consider stiffening rear anti-roll bar to promote rotation
Corner Apex Understeer
Cause: Rear rebound too low
Effect: Car pushes wide at apex, Hard to maintain minimum speed
Solution:
Increase rear rebound to delay rear settling
Lower front rebound to reduce front-end bite
Check ride height, too much rake can amplify apex understeer
Corner Exit Understeer
Cause: Rear slow bump too soft
Effect: Car struggles to rotate under throttle, Front tires lose grip
Solution:
Increase rear slow bump to control rearward pitch
Lower front rebound to reduce front-end bite
Consider adjusting differential to improve rotation off throttle
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