Vehicle suspension directly affects vehicle stability. How stable a vehicle is will affect wheel traction as well as passenger comfort. Since there are many different driving conditions in general, suspension engineering plays an important role in vehicle design. This is especially true when it comes to off-road suspension setups because the vehicle is being pushed in ways that are much more severe than normal, over-the-road, driving.
Is soft or stiff suspension better for off-road? Generally, stiffer suspension is better for off-road, though it does depend on what type of off-roading you’re doing. Each has their pros and cons: soft suspension maintains a smoother ride and provides more traction while stiff suspension is better suited for lift kits, components tend to be less expensive, and it has a higher weight rating.
This article will compare stiff suspension to soft suspension setups and what the positives and negatives of each might be. It will also cover when and where each type may be used, plus filling out what components constitute a soft or stiff suspension. It will also answer the question about swapping over from one style to the other and what might be involved in that project.
Types Of Suspension For Off-Roading
Modern vehicle suspension systems can be very technical. Even a relatively simple design involves a bit of math and measuring in its design. This is because the suspension lays a foundation for the rest of the vehicle, as well as in what ways the vehicle can perform. While there are many different set-ups, generally they break down into a softer suspension or a stiffer suspension. Softer suspension focuses more on passenger comfort while stiffer suspension tends to be more performance-oriented.
To break it down, most modern suspension consists of a spring assembly and a shock absorber. The mechanical force of the hardened spring keeps the wheels on the ground while holding up the rest of the vehicle. Generally, the spring is either a coil spring or a leaf spring, which are built to have a certain weight capacity rating but can also differ in height and compression ratio.
A shock absorber is a gas or fluid-filled strut that is designed to dampen the bounciness of the springs. While they do help the ride quality for the passengers, they also do a lot for maintaining traction and control. It is quite common nowadays to have a shock-spring combination, commonly called a strut. While there are different styles of struts, the benefits are the same: simple replacement, fine-tuning of damping and ride height, the option to customize spring/shock combo, and many other benefits.
Another way to categorize suspension systems is to differentiate between independent suspension and solid axle suspension. Independent suspension means each wheel is suspended independently from the others. This allows each wheel to rise or fall without affecting the other wheels, making for a generally smoother ride. Independent suspension utilizes constant velocity (CV) axles, which transfer power from the differential to the wheel while also bending to absorb and fit around the bouncing wheels.
The term solid axle simply refers to the axle beam that spans the width of the vehicle. Since the wheels are tied together that way, the rise and fall of one side affects the other side. As such, this style is more often used in performance settings, such as hauling, climbing, racing, etc. However, there are instances in which a vehicle may use an independent front suspension and a solid axle rear suspension. This allows the vehicle to utilize the benefits of each style at the same time.
Soft Suspension: Pros and Cons
Now that we have briefly gone over the different types of suspension, let’s look more specifically at a softer suspension for off-roading. Some pros of having a soft suspension setup are:
- More comfortable ride on rough terrain
- Better overall traction
A softer suspension is going to be better for passenger comfort, to a certain extent. If you are heading down dirt roads or trails that have a bit of an uneven surface at times, a soft suspension will usually be able to handle it. There are a lot of areas to explore that have this type of road, so it is possible to achieve some beautiful views without compromising comfort.
Generally speaking, a softer suspension does better at keeping the wheels on the ground. This, of course, helps maintain traction in almost all types of terrain. However, it is not always the best fit for specific types of terrain, such as rock crawling or other obstacles that a more rigid suspension would work better on.
There are some performance applications for a softer off-road suspension, such as trophy truck racing. While the suspension will be specifically tuned to the truck, desert racing requires a relatively soft suspension to eat up moderately large bumps while keeping the wheels on the ground and without shaking the driver loose.
While comfort and traction are a big deal when it comes to off-roading, there are some cons to having a soft suspension.
- Lower weight rating
- Generally more maintenance
- Not ideal for lift kits
- Increased risk of bottoming out while off-roading
Softer suspension is usually ideal for lighter vehicles. The weight rating is much lower, which can limit the overall weight of the vehicle, how many passengers you take, and what and how much gear you are bringing.
When it comes to maintenance, it depends on the make of each type of suspension. However, generally speaking, a softer suspension design is not as heavily built, meaning components will tend to wear out faster. Plus, replacing components in a strut assembly will take more work than replacing components of a leaf spring setup.
Adding a lift to a vehicle raises its center of gravity. That means the vehicle is less stable if equipped with a softer suspension. Typically, lifting the vehicle also involves stabilizing the vehicle to prevent body roll.
Stiff Suspension: Pros and Cons
While softer suspension has a lot going for it, some benefits of a stiffer suspension include:
- Better for lift kits
- Components tend to be less expensive
- Higher weight rating
As previously mentioned, a lift kit raises the vehicle’s center of gravity. A stiffer suspension will reduce body roll while driving as well as during difficult passes. A lift kit does a lot to make the vehicle more versatile. The raised clearance helps the car get over uneven terrain and keeps the engine and body further away from damaging obstacles.
A common stiff suspension setup is a solid axle with leaf springs. These tend to be very durable and can be easier to work on. For used parts, there are many options for solid axles, making them less expensive overall. Also, it is possible to trade out individual components at a time, which works better than trading out a whole strut assembly.
Also as mentioned above, a higher weight rating means a stiffer suspension. This means you will have an increased payload capacity, which can be useful depending on what type of off-roading you are doing.
Some cons for a stiffer suspension include:
- Rough ride
- Worse for traction
Basically, the cons of a stiff suspension are the compromise of most of what makes a soft suspension good. Most notably, the ride quality will be very rough. The stiff suspension will not absorb as much of the bumpiness. As such, prepare to be rattled around. This can also take its toll on the rest of the vehicle over time.
Since the shocks aren’t absorbing as much, the tires are more likely to bounce instead of staying on the ground. Of course, if a wheel is not on the ground, it cannot pull the vehicle along. So a stiffer suspension is better for lower-speed traversing where the likelihood of breaking loose at low speed is diminished.
Is There A Way To Change Your Vehicle To Have A Softer Or Stiffer Suspension?
It is possible to change how soft or stiff the suspension is. On higher-end strut assemblies, there are adjuster nuts on the shock that change the dampening level. This can give you the desired level of softness without having to change the whole assembly. These types of struts will be more expensive upfront. Also, it is possible to change out the coil spring on a strut to have a more rigid spring. This can be a bit labor-intensive, so it isn’t a quick switch.
For a solid axle, it is possible to swap out leaf springs and shocks to be stiffer. This usually involves just unbolting and rebolting things back together, which isn’t terrible in the right conditions. Also, adding a stabilizer link or upgrading the preexisting one can help tighten up the suspension. This can also be unbolted if things need to run softer. You can learn more by reading our article “How Can I Make My Suspension Less Stiff?
Related Questions
Why is off-road suspension stiff? Off-road suspension is stiff to better control the sway and impact of the vehicle under dynamic loads. Off-road suspension should always be stiffer than the suspension of an average street vehicle because they’re built for different purposes. Stiffer suspension allows an off-road vehicle to not sway back and forth uncontrollably and maintain a smoother ride. Click here to view the full article.
