How to Choose the Best Suspension Kit for Your Off-Road Vehicle
Upgrading your suspension is one of the most important decisions you’ll make when building out an off-road vehicle. Adding a lift will not only enhance your vehicle’s appearance, but a properly set up suspension will play a crucial role in ride comfort, stability, and capability out on the trails. If you're building a weekend warrior or planning for a fully outfitted overlander, understanding the basics of a suspension system will help you make smarter and more effective choices for your setup.
In this guide, I’ll break down what a suspension actually does, what affects ride and handling, and what to consider when purchasing a kit. And I’ll help you decide which of the ARB Old Man Emu kits are right for your build.
What Suspension Actually Does
Your suspension system supports the weight of your vehicle, smooths out uneven terrain, keeps your tires in contact with the ground so you stay in control. It includes several key components: springs (coil or leaf), shocks or struts, and a few other supporting parts like control arms, torsion bars, sway bars, bump stops and steering dampers depending on your vehicle.
Since most of this guide is about helping you figure out the best suspension for your build, it’s worth understanding the basics. Springs carry the weight and determine how high your rig sits. Shocks manage movement and absorb bumps, keeping things smooth and stable when the trail gets rough.
Let’s jump in.
Key Questions to Ask Before Choosing a Suspension Kit
Before diving into the technicalities of a suspension, it’s important to think through how you actually plan to use your vehicle. This step helps narrow down what kind of suspension will best suit your needs.
You’ll want to identify your goals with your build. Will it be a daily driver with occasional trail use, or are you building it into a full-time overlander? Do you plan to carry extra weight regularly, or only during certain trips? Based on your answers, this will help determine what spring rate, shock type, and additional components you’ll need.
How to Choose the Right Springs for Your Off-Road Suspension
As I mentioned above, the springs are what will carry the weight of your rig and determine how lifted it will be. But they do a lot more than that. The right spring rate can make a big difference in how your vehicle handles when it’s loaded down and how comfortable the ride feels. Getting the right setup helps with stability, control, and long-term performance. But before you pick a set of springs out, there are a few important things to consider, so let’s break it down.
Load Considerations: Constant vs. Variable Weight
Your suspension will work best when it’s matched to the load it’s carrying, aka how much it will weigh. There are two types of loads to understand: constant and variable.
Constant load refers to the permanent accessories and gear mounted to your vehicle. Think steel bumpers, winches, drawer systems, rooftop tents, and underbody armor.
Variable load includes everything that comes and goes. This will be your passengers, water containers, recovery gear, camping supplies, etc.
Choosing springs that are too soft for your load will lead to sagging and premature wear. On the other side, springs that are too stiff for your setup can create an uncomfortable ride when the vehicle isn’t loaded down. The solution, you want to match your springs to your actual load, not just what you plan to carry occasionally, but what you will be carrying everyday. Remember if you plan to go with springs for your setup, you can always change them as your build evolves, but this will cost more money, that’s why it’s best to understand your goals before anything else.
Now that you have figured out how much weight you plan on carrying you can determine your spring rate.
Spring Rate and Ride Quality
Spring rate refers to the amount of force needed to compress a spring. This is where you will see how your ride quality is. Typically you will see light-, medium-, and heavy-duty spring options.
Light springs compress more easily and provide a soft, comfortable feel on-road, but they can bottom out or sag when carrying extra weight. Medium springs are often the best balance for rigs that carry moderate gear on a regular basis. And heavy-duty springs are much stiffer and designed to handle full-time overland loads, but they can feel too firm if the vehicle is unloaded.
Here’s a quick guide:
Note: Having rock slides, side steps, and roof racks will distribute the weight to both the front and rear of your vehicle.
Ride comfort, articulation, and suspension longevity are all tied to spring rate. If you’ve ever had a bouncy ride or noticed your rig sitting uneven, chances are the springs weren’t quite right for your setup. Getting this part dialed in can make a big difference in how your vehicle feels and performs. And now you get to decide how high you want your lift!
Fine-Tuning Ride Height: Preload vs. Top-Hat Spacers
When it comes to dialing in your suspension lift and correcting lean (if you have any), it’s important to understand the difference between preload and top-hat spacers and how each one affects your setup.
Preload is all about adding a bit of compression to the spring before it’s installed. That extra tension helps adjust ride height and can even out minor lean, without changing how the spring actually performs. Preload is usually the better long-term option.
Most of the OME shocks, you get stackable preload spacers in two sizes: 7.5mm and 17.5mm. Flip them in different ways and you’ll get four preload options: 5mm, 10mm, 15mm, or 20mm. These will be able to balance out uneven weight and fine-tune your lift after adding accessories like a bumper or winch, all while staying within the intended lift range for your coil.
We also offer another option specifically for our MT64 shocks. On these, you will see six spring position grooves built into the shock body. These let you adjust spring seat height in 5mm increments, giving you really fine control over your lift.
Top-hat spacers work a little differently. They sit on top of the coilover and raise your vehicle without actually compressing the spring. While that might sound like an easy way to lift your rig, it can lead to overextending your suspension. Ultimately this will reduce how much your suspension can compress, which will limit performance and make your ride feel harsh over bumps.
What Are Your Options at ARB?
We might be a little biased, but every kit we’ve put together is designed to make it easy to find the right springs for your setup. Each one is carefully tuned to match your vehicle’s weight and how you actually use it, with light-, medium-, and heavy-duty options that cover everything from daily drivers to fully loaded overlanders.
Our OME coil springs are shot-peened and scragged to hold their shape over time, and our leaf packs use a multi-stage design that adjusts to the weight you’re carrying, so you get the support you need without ever having to sacrifice comfort while driving.
But the best part is how straightforward we’ve made the spring selection process. Instead of digging through a long list of part numbers, you simply choose the kit that matches your front and rear loads. That’s it! From there, you can fine-tune your lift height using preload collars.
Now time to pick the next part of your suspension: shocks and struts.
How to Choose the Right Shocks & Struts for Your Off-Road Suspension
Shocks and struts work alongside your springs to absorb bumps, smooth out the ride, and keep your tires planted. In this section, we’ll walk through what each part does, how they differ, and what to look for when picking your suspension kit.
Shocks and Struts: What’s the Difference?
Shocks are stand-alone components that help manage how your suspension moves. They keep your rig from bouncing around too much, control body roll, and make sure your tires stay on the ground. They don’t carry the weight of your vehicle but they do a lot to shape how your vehicle feels and performs.
Struts do all that and more. Unlike shocks, struts are a structural part of your suspension system. They provide support and stability by helping hold the suspension together.
Here’s a quick look at ARB’s shock lineup:
Nitrocharger Sport
Nitrocharger Plus
MT64
Understanding Coilovers
Coilovers combine a coil spring and shock absorber into an all-in-one unit. The spring wraps around the shock body, which saves space and while improving performance. But the best part about these, is they are fully adjustable.
With coilovers, you can dial in ride height, spring preload, and damping settings depending on your gear load or driving style. They typically offer more travel than traditional setups too, which means better articulation and off-road performance.
ARB offers the BP-51 coilovers that are adjustable, durable, and built with internal bypass technology for the best of both comfort and control.
But are coilovers worth the extra cost? If you’re regularly hitting trails, hauling different gear setups, or just want more control over how your suspension behaves, coilovers are absolutely worth it. If you’re sticking to forest roads or lighter trails, they might be more than you need.
ARB’s Shock Design Types
We mentioned our different shock line-up above, but how do they differ? Let’s walk through our shock options!
Twin-tube shocks are the most common design out there. They use an inner working cylinder for the piston and oil, and an outer reservoir to store excess fluid and nitrogen gas. These shocks are built to handle daily driving and moderate off-road use.
ARB’s Nitrocharger Sport and Plus shocks use this twin-tube setup. They’re great for rigs that see a mix of city driving and weekend trail time.
Monotube shocks house both the oil and gas in a single cylinder, separated by a floating piston. They react faster to changing terrain and manage heat much better than twin-tube designs.
ARB’s MT64 shocks are monotube shocks. They’re perfect for heavier builds and sustained off-road use.
Internal bypass shocks are all about control where it matters most. They use something called position-sensitive damping, which basically means the shock behaves differently depending on how far it’s compressed. You’ll get a nice, smooth ride through the middle of the stroke but as you near full compression or extension, the shock firms up to give you better control when things get rough.
ARB’s BP-51s, (yes, the “BP” stands for “bypass”), are internal bypass shocks. They have built-in channels that let oil flow around the piston in certain zones, softening the ride when needed but kicking in more resistance when you need it most. And because they come with remote reservoirs, you get extra oil capacity and better cooling which is ideal for long, technical trails where heat can really start to build.
Suspension Adjustability: What You Can Tune and Why It Matters
When we talk about adjustable suspension, we’re usually talking about two things: compression and rebound.
Compression damping controls how fast your shock compresses when your wheel hits a bump. A softer compression gives you a smoother ride. A stiffer compression helps with control on rough terrain or when carrying extra weight.
Rebound damping controls how quickly the shock returns to its normal length after being compressed. If rebound is too fast, your rig can feel bouncy. Too slow, and it feels sluggish or unresponsive.
Getting both dialed in makes a huge difference in how your vehicle handles. Now let’s break down the different types of adjustable suspension and how they work.
Adjustable vs. Fixed Shocks
Adjustable shocks let you take control over how your suspension feels. Want a smooth, comfortable ride on the highway? Soften things up. Loaded down with gear and hitting the trails? Stiffen it up for a more controlled and table ride. The ability to tune compression and rebound is a huge benefit, especially as your build evolves or your terrain changes.
Fixed shocks are pre-tuned at the factory. You don’t have to mess with any settings, they’re designed to perform well for a specific load and use case. If you’re looking for a simple, reliable solution that just works, fixed shocks are a great choice.
Adjustable Shocks vs. Coilovers: What’s the Difference?
Adjustable shocks and coilovers aren’t the same.
Adjustable shocks are all about control. They let you change how soft or firm your suspension feels, like how fast it compresses and rebounds. They won’t change your ride height or spring rate, but they can make a big difference in how your rig handles.
Coilovers, as you already know, are the full package. You’ve got a coil spring wrapped around the shock, and everything’s built to work together. With coilovers, you can adjust ride height, preload, and damping too, all in one setup.
Our BP-51s are a great option for those looking to get the most out of their setup. Most adjustable shocks only allow you to change the compression, but our kit lets you dial in compression and rebound separately. That means you can really fine-tune how your rig behaves.
If you want full control and flexibility, go with coilovers. But if you’re happy with your springs and just want to improve how your rig handles, adjustable shocks are still a great upgrade.
What Lifting Your Vehicle Does to Suspension Geometry
Lifting your rig will give you better clearance for bigger tires and trail obstacles, but did you know that it can change the geometry of your suspension? That means the angles between key components like your control arms, ball joints, and steering linkage are no longer in their factory positions.
When that geometry is off, a few things can happen:
Alignment becomes harder to dial in, especially caster angle, which affects high-speed stability and steering feel
Ball joints operate at steeper angles, which can limit suspension travel and lead to premature wear
You might not get the full benefit of your suspension upgrade, because components are now working against each other
That’s where aftermarket upper control arms (UCAs) come in.
Our Old Man Emu UCAs are built specifically to solve this problem. They help bring your alignment back into spec, improve ball joint angles, and make room for bigger coilovers or longer-travel shocks.
If you’re adding a suspension lift, especially anything over 2 inches, upgrading your UCAs is necessary. These are just a part of what will help your suspension perform the best.
Why Old Man Emu Should be Your First Choice
There’s a reason our suspension kits have been trusted for decades, they just work. No matter how you plan on building your rig, we deliver real-world performance without all the guesswork or unnecessary complexity.
We design our OME kits to work together from the start. You’ll get:
Spring options tailored to your vehicle’s weight, gear, and setup
A choice of shock types, twin-tube, monotube, or internal bypass, so you can pick what fits your driving style
The option for adjustability, letting you fine-tune your suspension a bit more
Tested and tuned in the real world
Most importantly, everything is made to fit and perform as a complete system. You’re not left piecing together parts or hoping it all works out. We’ve already done the testing—so you can install with confidence and hit the road.
Final Thoughts
Suspension isn’t just about the lift. It’s about how your vehicle actually handles once you’ve got that extra clearance. No matter what trails you plan on hitting or how built you want your rig to be, the right suspension setup makes all the difference.
Now that you’ve got a better understanding of what goes into choosing an aftermarket suspension, here comes the fun part—picking the setup that fits your build. If you want something that’s built for the real world, takes the guesswork out of pairing components, and leaves room to grow, our Old Man Emu lineup has you covered. It’s tested, proven, and ready when you are.
