Off-road driving creates a whole set of unique requirements for shock absorbers. Basically you want the same off-road characteristics as in passenger car shocks; control for good cornering and the most comfortable driving possible. However, in the case of off-road driving, you also want good suspension flex.

Lifted 4X4s, which have much heavier tires, store more heat. And if you plan on driving at high speeds, as in the case of desert racing, then your shock absorbers are working much harder, causing much more heat.

excessive heating

This heat buildup places a couple of requirements on the shock absorbers you need for your lifted 4X4. Both are related to adding more oil to the shock. If the shock absorber oil overheats, it can foam and rupture. When this happens, the shock can no longer do the job it was designed to do.

The first difference from 4X4 shocks is that they have much larger bodies. The length also increases for raised vehicles, but the diameter of the shock body also increases, depending on the space available under the vehicle, to increase the amount of oil it can hold.

The second way to increase oil volume is to add a remote oil reservoir. This option was created specifically for off-road racing and has become a popular solution for all types of 4X4s.

A remote reservoir allows you to use a smaller diameter shock body, while increasing the volume of oil by keeping it in a separate reservoir that is connected to the shock by a hose or tube. The separate oil reservoir also allows for better heat dissipation.

Coilover shock absorber

A coilover shock is a type of shock you will see frequently on modified 4X4s. This type of shock absorber combines a shock absorber with a spring, all in a single unit. They are popular in custom setups because you can combine both components while using the same amount of space.

Coilover shocks also allow the use of longer springs than a traditional coil spring suspension because the springs are fully contained. You can easily change the springs to change the spring tension or “frequency” as it is called.

You can also add springs for a double or triple rate spring by adding more springs with different rates in the coil spring set. This will give you a smoother ride during the first few inches of compression and a more aggressive spring rate for situations where the suspension travel is beyond the normal range.

Almost all of today’s light-duty pickup trucks come with direct-spring shock absorbers from the factory. This has created an opportunity for traditional shock absorber companies to offer a combination of an improved shock absorber and lifter in a single component.

shock valve

The shock valve is usually designed specifically for each individual application. For example, a high-quality shock to fit a truck that is raised six inches has been valved to accommodate the larger tires and handling characteristics of that vehicle.

Some shocks also come with user adjustable valving. This allows you to soften hits when you want, such as with rock crawling. And tighten them for towing or general highway driving.