Besides tires, bumpers, and undercarriage protection, the most important modification you may consider for your off-road truck is a suspension mod. There are a lot of different types of suspension systems available, each of which has its own pros and cons for off-roading. Choosing the right one depends on what you like to do with your truck and which suspension can help you do it best.
Solid Axle Suspensions
Solid axle suspensions are some of the oldest suspension configurations still in use today for off-road trucks. They consist of a single, solid, unjointed axle that is supported with either a leaf spring system or a 4-link system.
^^^^Leaf Spring Systems - Leaf springs are suspension springs made by laying multiple layers of spring steel together. The stack of spring leafs are mounted to the frame and the axle is mounted to the leaf springs. Leaf spring suspensions are very rugged and durable and can function well under high loads. They can also be modified to add lift to trucks needing ground clearance. The main drawback with leaf spring systems is they cannot be fine-tuned in the way same way that other systems can be. Adjustment is limited to how the leafs can be configured.
^^^^4-Link Systems - A 4-link suspension is a solid axle system that uses coil springs instead of leaf springs. This setup consists of 4 extension support arms (two on each end of the axle) that bolt from the axle to the truck frame. 4-link suspension provides important stability for solid axles, restricting backward and forward axle motion based on the way it is tuned. Yet the axle can still move freely up and down. The link arms can be adjusted for length and angle to fine tune the suspension depending on what type of terrain the off-roader will be driven over. The downside to 4-link suspensions is they do not corner well. They are popular for high-speed desert racing since the suspension is quick to respond to keeping the tires on the ground.
Twin Beam Systems
Although they are not a true independent suspension, twin beam suspensions are a midpoint between independent and solid axle systems. It is something you may want to consider for your off-roading truck. They consist of two solid axles, each of which is mounted to the wheel on one end and the frame on the other end using a pivoting mount. The axles are supported by coil springs and can be length-adjusted to increase clearance and wheel travel as required.
Twin beam suspensions are designed to reduce bump steer and suitable for many types of terrain. They are another favorite of desert racers due to the amount of wheel clearance possible. They can cause unstable wheel camber as well as uneven tire wear.
Double Wishbone Systems
Double wishbone suspensions, also called A-arm suspensions, are true independent systems consisting of two control arms that extend from each wheel to join together in the middle into a steering knuckle. Supported by various types of coil springs, double wishbone suspensions allow each wheel to move independently over uneven terrain. The A-arms keep the wheel parallel as the suspension works, keeping the steering more accurate regardless of how the suspension is compressed.
There is a wide variety of coil springs, torsion bars, and other accessories available for use with these systems to add lift and improve performance for off-road use. When a vehicle is modified using this suspension system, highway performance is affected. So you should only consider this type for use with a dedicated off-road truck.
Although every suspension achieves the same basic function, the differences in design make them more or less suitable for various off-roading activities. To get the most from your truck or Jeep, whether you are looking for wheel travel, ground clearance, or a combination of the two, consider what activities you enjoy and what capabilities your truck needs. The right suspension, along with the right tires and important upgrades like the right truck bumpers, can give you the traction performance you need to succeed!