There are plenty of trucks these days advertised as rugged and capable, but it can be confusing to know what to look for exactly when choosing an off-road vehicle. Choosing an off- road suspension can be particularly tricky because in addition to many options, there are even more modifications.
How do you choose off-road suspension? What is most important is knowing how you plan to use the truck. The more the suspension is designed for off road, the worse it will perform on a smooth road. A stock leaf suspension is enough for light off roading, coil spring suspension upgrades are better. Some extreme suspensions are not street legal.
The type of suspension you choose also depends on what type of off roading you plan to do. Speeding through the desert and blasting over whoops and dunes requires a much different suspension than crawling up and over rocky paths. Many people want to raise their truck’s suspension simply to add bigger tires for aesthetic reasons.
How to Choose Off-Road Suspension
There are a lot of options when picking an off-road suspension. Not only are there several types of suspensions, but you also will need to pick tires, shocks, and many other components that affect how your truck rides. Each choice has significant consequences on your outcome, so it’s important to consider all these factors.
When choosing an off-road suspension, make sure you ask yourself the following 4 questions.
- How do you plan to use the off-road vehicle?
- What size tires do you want?
- How much mechanical know-how do you have?
- What is your budget?
How do you Plan to Use the Off-Road Vehicle?
The amount you plan to actually drive off-road plays an important role in choosing a suspension. On one end of the spectrum are people who only drive on paved roads, and on the other end is having a dedicated off-road vehicle that you tow to the location and use only on site. Of course, what is more common is people that do some of each.
The suspension of your vehicle exists on a similar gradient.
- Some trucks are designed for a comfortable ride on smooth roads
- Some trucks are designed to be able to carry hundreds of pounds of cargo.
- Other trucks are designed to keep your tires on the ground no matter what type of terrain you drive over.
The more your suspension is designed for off-roading, the worse it will handle on the highway. On the extreme end, trucks can be modified to the point where it is no longer legal to drive them on the road at all.
What Size Tires do you Want?
The type of suspension you need can usually be determined by what size tire you want. The larger your tires are, the bigger obstacles you can drive over without getting stuck. Larger the tires, likewise, require more extreme suspension packages to provide the height and strength needed. Some people simply like the look of large tires and don’t plan to drive off road at all.
- Stock to 33 Inches. For tires up to 33 inches, you can stick with the solid axle and leaf spring suspension that is standard on most trucks. This suspension is designed for maximum highway driving comfort but can also handle light to moderate off roading.
A simple leveling or body lift kit can add enough height for these tires without affecting how the truck handles.
- 33 to 35 Inches. For tires of this size, you probably need to use a coil spring suspension. At this height you may also need to modify the steering connections with front and rear track bars and realign the front end. The more you raise the truck’s center of gravity, the less stable it will be.
- 35 to 37 Inches (or More). As your tire size gets this big, major modifications will be needed. Front and rear track bars will re-center the axles, and front and rear driveshafts will be needed as well.
How Much Mechanical Know-How Do You Have?
Different off-road suspensions will require different amounts of mechanical know how, to both install and maintain. Some kits, especially leveling and budget lift kits, require relatively low amounts of work. The more extreme suspension kits, however, require extensive metal cutting and welding to replace the stock options.
Before choosing an off-road suspension package, make sure you have the mechanical know how to install and maintain it. Or you should at least be able to afford to have a trusted shop do it for you.
What is your Budget?
Speaking of which, your budget is a major factor in picking an off-road suspension. The more extreme suspensions cost more because they require more (and more heavy duty) equipment to replace the stock options. They also require more labor to install and maintain. Also, off road suspensions can further reduce the gas mileage of trucks, so they will cost even more to run.
Types of Suspension
Before choosing an off-road suspension, you first must know what options are out there. Different types of suspension are designed for
- different uses,
- have different drawbacks,
- and cost different amounts.
Whatever the type, the purpose of the suspension is to keep the tire in contact with the ground, so you have maximum traction.
Solid Axles Versus Independent Suspension
The biggest debate among off-roaders is whether it’s better to have a solid axle or independent suspension. Solid axle suspension means that the tires are connected by a straight rod in the back and the rear. As such, the tires move together as a single unit. Independent suspension systems allow the tires to move independently.
Which is better is really a matter of personal preference. As a general rule, solid axles are better at climbing over rocks, and an independent suspension is better at handling bumps when traveling at high speeds on a straightaway. If you only plan on doing one type of off-roading, the choice can be simple. If you plan on doing a lot of different styles, the choice is open to debate.
Every year at the King of the Hammers, a race of all the off-road paths in Johnson Valley, there is great debate over which type will win because the track covers a wide range of terrain types. Over the years, the King of the Hammers has been won by both types of suspension in equal amounts, keeping the debate far from settled.
Leaf Spring Suspension
Leaf spring suspension is the cheapest and most common type of suspension. It is very often the stock option on a truck. The system consists of layers of curved spring steel that return to their original shape after being depressed. The axle is attached at the midpoint of the leaf’s arc. One end of the leaf is attached firmly to the frame, while the other is allowed to slide.
When weight pushes down leaf spring, the curved steel flattens. The loose end (mounted with a shackle) slides to accommodate this change, and the axle is squeezed closer to the frame. When the force is removed, the leafs spring back to their original curve.
Different leafs of varying sizes are connected to provide a smooth ride under varying conditions. There is also often a second set of leaf springs, made of thicker and longer steel leafs, that are designed to be engaged only when there is a heavy load in the bed of the truck. In this way a smooth ride can be had when travelling empty or hauling a heavy load.
Leaf spring suspensions can be modified fairly simply by adding a block between the spring and the axle. This should not be done to add more than a few inches, however, because the extra height can increase the chance of axle warp and wear out the driveshaft. Modification can also be achieved by adding leafs, though this will make the ride stiffer.
Radius Arm with Coil Spring Suspension
Some people prefer coil springs because they are more compact than leaf springs. They are not as effective at dispersing weight, though, and can usually only hold the weight of the truck. They are not suitable for trucks meant to carry heavy loads. Most often they are found in the front end where there is limited space.
The axel is connected to the frame by stiff arms. The axle is able to move up and down as the arm pivots, but this action also changes the wheel’s caster angle and requires a track bar to keep the axle centered on the frame.
4 Link Suspension
There are two types of 4 link suspension that are essentially modified versions of radius arm suspension:
- Parallel 4 link suspension, and
- Triangulated 4 link suspension.
Parallel 4 link suspension replaces the solid radius arm with an arm made of 2 links (top and bottom) that pivot at the connection points with both the frame and the axle. This allows the axle to keep its same orientation with the ground, so the caster angle doesn’t change. A track bar is still required to keep it centered on the frame.
Parallel 4 link suspension offers better ride quality and handling than typical radius arm suspension. It does, however, come at the expense of strength as the increased points of pivot increase the chance of wear.
Triangulated 4 link suspension makes use of top links that are wider at the frame narrow at the axel, and lower links mounted at the opposite orientation. When the links are mounted at a great enough angle, side to side motion is resisted, so a track bar is not needed to keep the axle centered.
Independent Front Suspension
Independent front suspension typically involves A arms with unequal length sides which are mounted perpendicular to the frame. The wheels are allowed to move independently from each other because the arms pivot at both ends and are kept parallel to the ground. This is due to the fact the top is shorter than the bottom. It keeps the camber and caster of the wheels aligned.
This suspension is found in both 2 wheel drive, which is better for racing, and 4 wheel drive, which is popular because it is more compact.
Twin-Traction Beam Suspension
Beam suspension is a sort of combination of solid axle and independent suspension. Each wheel is attached to a long beam that is attached to the frame on the opposite side of the truck and allowed to pivot. At the center, the beams are attached by a U joint that allows them to move independently. The result is as if a solid axle were allowed to bend at the center.
This gives the strength of a solid axle because the long beams are able to disperse stress and compression over a larger area. It also allows for the freedom of movement of an independent system and a great shock ratio. One thing to watch for is the pivot of the long arms changes the camber of the wheels, allowing uneven wear on the tires.
Double Wishbone Suspension
Double wishbone suspension, also called A arm suspension, suspends each wheel independently. The axel is joined with spherical bearings or a heim joint. This allows the wheels to stay in perfect alignment with the road, improving the truck’s steering. This setup is ideal for on road driving, but usually requires modification for off road driving.
Types of Suspension Lifts
Manufacturers have a lot to consider when producing trucks for public purchase. They need to balance:
- Performance,
- Safety
- And costs
They have to keep all the specifications within certain safety guidelines, have a product whose power they can advertise, and be able to turn a profit when all is said and done.
For these reasons, stock trucks that come from the manufacturer aren’t going to be designed to maximum off road capability. Instead, they are designed for the best ride on the road, because they know that most buyers will never drive off road, and even those who do will still do the majority of their driving on the asphalt. They are only off road enough to be advertised as such.
If you are serious about off roading, you will probably need to do a bit of modification in order to make it over all the rocks you want. At the simple end, you can lift the body of the truck enough to put on larger tires. On the extreme end, you might end up chopping out all of the standard suspension and replacing it with heavy duty parts. It’s up to you.
Keep in mind, however, that the more you modify your truck, the more you lose the safety and dependability that the manufacturer worked so hard to produce. Raising the suspension:
- Raises the center of gravity, which makes it more likely to roll,
- Reduces the mileage per gallon, and
- Changes the angles that steering, and driveshaft components meet, increasing risk of wear.
None – Stock Options
The first option, of course, is to do nothing. Before you get carried away with expensive modifications, take a serious look at what your truck is capable of, and how you will actually use it. Sure, you may have big dreams of blasting through the uncharted wilderness, over logs and up waterfalls, but how likely are you to actually explore anything rougher than a fire road?
There have been many before you who emptied the wallets upgrading their rigs to be the biggest and beefiest things they could afford, only to see an unmodified stock jeep on the path right behind them. Stock options can usually handle more than you would expect, so make sure you are realistic about your needs before forking over the cash.
Leveling Kit
Perhaps the biggest reason for lifting your ride is aesthetic reasons. You might just want your truck to look right. Many trucks, especially flat bed and pickup trucks, are designed to sit an inch or two lower in the front than in the back. This is purposeful, so that the truck rides evenly when there is a heavy load in the back. When empty, though, it can look a little bit off.
Leveling kits only cost a couple hundred dollars and are designed to raise the front a couple inches and the back not quite as much, leveling out the truck’s frame. They are usually easy to install, as they are just blocks that are inserted between the spring and the axle to give a little bit of lift.
This small modification does change the focal point at which the leaf springs bend, but as long as the lift is only a couple of inches, there isn’t much risk of warping the axle or deforming the spring. A leveling kit should be able to even out your truck, and might even give enough extra height to increase the tire size a couple of inches.
Body Lift
Body lift kits work in the same way as leveling kits, except that the goal is definitely to add enough height to put on bigger tires. Bigger tires are the surest way to increase off road capacity because it is the only way to increase the clearance from the road to the axle. Lifting the body will also increase the vehicle’s:
- Approach,
- Break over, and
- Departure angles.
While it is relatively straightforward to add spacers on the rear axle, more care must be taken when lifting the front end. Because the front wheels turn in order to steer the truck, there is additional sheer torque applied to these spacers. Risk of failure is therefore higher.
Economy or Budget Boost Lift
If you want a little lift on an equally little budget, economy budget boost lift kits will give you what you need. They typically work by adding polyurethane coil spacers on top of the coil springs that came standard on your truck. If lifting more than a few inches, you will also need:
- Shock extensions,
- Longer sway bar links,
- Brake line extension brackets, and
- Trackbar brackets
The more height you want, the more modifications you will have to make.
Coil Spring Lift
There is only so far you can lift your truck’s body if you have leaf springs. The added spacers between the leaf springs adjust the way the leaf springs flatten under pressure because the focal point is changed This can cause axle warp and other failure. If you are lifting more than a few inches, you will either need to upgrade to or replace your existing coil springs.
Even if your truck already has coil springs, the stock options will not be long enough to reach the heights you want. Coil spring lift kits, therefore, include longer, stiffer springs, as well as longer shocks, extended brake lines, bump stops, trackbar brackets and sway bar links. You also need to fix the pinion angle by replacing the control bars and track bars to reduce vibration.
Short or Mid Arm Lift
Just as there is a limit on how high you can raise a body using leaf springs, there also is there a limit on how long your coil springs can be. At some point, if you want even more lift and better articulation, you will need to replace the coil spring suspension with an A arm suspension system.
At this level, you are replacing the entire suspension system, except, perhaps, the driveshaft. Obviously, this is a more extreme and more expensive option. As long as you keep the arm size in the short to mid length, however, you can make use of factory control arm mounts on the frame and the axle, and thereby avoid any major metal cutting and welding.
Long Arm Lift
If you are going all out with a long arm suspension, you’d better know what you are doing. Installation will require cutting out of factory brackets and welding in new, heavy duty control arm brackets. You’ll also have to replace the entire driveshaft. It is, however, the only way to have the extreme articulation long arm suspension offers.
Clearance
Clearance is one of the most important factors in off roading. No matter how rugged your frame is, how stiff your springs, or how much your wheels articulate, you can’t climb over any rocks your bumper hits. Before you go to the trouble of modifying your truck’s suspension to get additional lift, think a bit about what type of clearance you need.
For marketing purposes, it’s common to see a truck’s ground clearance advertised. This is the distance from the road to the lowest piece of truck that isn’t the wheels themselves. Independent suspension trucks have higher ground clearance, for example, than solid axle trucks because the latter always has a solid bar running across at the height of the center of the wheels.
Manufacturers like to advertise ground height as if it is an accurate measure of a truck’s off-road capabilities. In actuality, however, ground clearance is only one factor. It really only measures how tall some isolated object on the road needs to be to affect the truck driving over the top of it untouched. If you plan to actually drive up and over any obstacles, there is more to consider.
There are a few key measurements when talking about your vehicle’s clearance.
- Approach Angle is the measure of the angle from your front tire to your bumper (or the lowest point in front of your front tires). It affects how steep of an angle you can begin to climb.
- Break Over Angle is the angle from the lowest point on your vehicle meets the line from the bottom to the top of opposite tires. The smaller it is, the more likely you are to be caught straddling your obstacle.
- Departure Angle is the angle from the rear tire to the rear bumper (or lowest point behind the rear tires).
In all instances, the higher the angle, the better equipped your truck is at getting over off road obstacles.
Installing larger tires is the only way to increase overall ground clearance, in fact, larger tires will improve all of these angles, since they lift all aspects of the truck’s frame. However, larger tires alone cannot make up for vehicle design. A 2 door jeep, for instance, will always be more agile than a 4 door jeep simply because the wheelbase is more compact.
Conclusion
It’s important to choose the proper off-road suspension for your vehicle. Your truck will drive and handle very differently on the road the more you modify it to perform off-road. It’s important to know what you want out of your vehicle before cheesing a suspension.
