What Does a Shock Absorber Do on Your 4x4?
There’s a lot of confusion about shock absorbers and their role in a 4x4’s suspension system. Contrary to the name, a shock absorber doesn’t actually absorb shocks – it controls the movement of the springs and suspension to keep your tyres in contact with the road or trail. This ensures safe handling, improved stability, and a smoother ride over uneven surfaces.
How Shock Absorbers Work
Most 4x4s use telescopic hydraulic shock absorbers, which may be:
- Gas-charged shocks (“gas shocks”)
- Foam cell technology shocks
- Mono-tube or twin-tube designs
A shock absorber, technically a damper, works by restricting the flow of hydraulic fluid inside as the suspension compresses or extends. The fluid flows through valves in the piston and foot valve, creating damping resistance. This resistance controls spring movement, ensuring the vehicle doesn’t bounce uncontrollably over bumps or rough terrain.
In simple terms, the shock absorber converts the energy from spring movement into heat, which is then dissipated through the shock body. You can actually feel this by touching your shocks after driving a few kilometres on a corrugated road.
What Shock Absorbers Don’t Do
- They don’t support the vehicle’s weight: Springs hold the chassis above the axles.
- They don’t determine ride height: Longer shocks alone won’t lift your 4x4.
- They don’t eliminate bumps: They control energy transferred from the springs, improving stability and comfort.
Matching Shocks to Your Suspension
The damping performance of a shock depends on piston and valve design. The stiffer the springs or the heavier the load, the more control the shock must provide. Fitting mismatched shocks and springs can lead to:
- Over-damping or harsh rides
- Uncontrolled movement or unsafe handling
- Poor performance on-road or off-road
Adjustable shocks are ideal but rare and often expensive. The key is to assess your vehicle’s primary use—whether overlanding, towing, or off-roading—and choose shocks that match your suspension requirements.
Key Takeaways
- Shock absorbers control spring movement, not vehicle height.
- They convert suspension energy into heat, keeping the ride stable.
- Matching shocks to springs and load is critical for safety and comfort.
- Adjustable or aftermarket shocks can help tailor your 4x4’s performance for specific needs.