On the surface, upgrading an off-road vehicle’s suspension system might seem like a straightforward proposition. After all, if an aftermarket suspension component bolts right up to the same mounting points as the factory part, it should just “work,” right?
However, whether we're talking about a championship-winning trophy truck or a daily-driven SUV, the reality is that a properly developed suspension system is backed by sophisticated engineering to ensure that all the components work in concert. When you alter one aspect of that system, it can have a profound effect on how the other aspects of the suspension function. Without a solid understanding of how a change will affect the overall package, it can lead to trouble down the road.
“We see it all the time: Someone just starts throwing parts at their build, and then they roll into a shop and the mechanic tells them, ‘Hey, we can’t align this,’” says Bryan Grigsby, Off-Road Suspension Business Unit Director for Holley Performance Brands. “That’s when they suddenly discover that the steps they’ve taken have negatively impacted the suspension’s ability to do its job. And that can lead to a lot of frustration and additional expenses.”
The good news is that these issues are correctable – or entirely preventable – if you’re armed with the right knowledge. Here, we’ll take a look at eight of the most common off-road suspension issues that Grigsby and the team at ADS Off-Road Suspension encounter, and find out what you can do to resolve or avoid them altogether.
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“A spacer-style kit might be fine for someone just driving around on paved roads and trying to achieve a certain look, but they’re definitely not for performance,” Grigsby explains. “With a spacer, you’re adding a considerable amount of spring preload to a factory coil spring that was never designed to operate in that manner."
“That means you’re going to wear out those springs quicker, and that preload will negatively impact the ride quality,” he continues. “You’re also placing the factory strut in the wrong position – when the engineers designed that suspension package, they had a certain static ride height in mind. The compression and rebound damping zones were set for that specific height. With this spacer, the suspension will behave erratically: The ride will be stiff, the bump zone will be misplaced, the rebound will be too fast, and you’ll limit the droop of the shock from static ride height.”
Instead of opting for a spacer kit, Grigsby points to better options that enhance the vehicle’s off-road performance without compromising functionality.
“At the ground level, you should focus on a replacement strut. Entry-level options will retain the factory spring, and the top hat will be positioned differently on the lower seat. The shock will be valved for the OE spring and its orientation, allowing the suspension to operate correctly.”
For those seeking a more comprehensive solution, he suggests checking out a basic coil-over setup. “That will give you a properly matched spring rate and shock valving, along with a more robust top hat than the factory one.”
Further up the ladder, a more capable coil-over with greater adjustability can offer even better off-road capability. “With the ADS Mesa series, for example, you get a direct-fit coil-over that provides raised ride height with spring rates and valving optimized for it, along with the benefits of a larger diameter body, a purpose-built top hat, a high-flow piston, and race shock architecture.”
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Grigsby tells us that, regardless of whether an enthusiast opts for a spacer kit, strut, or full coil-over, people often neglect to correct the changes these modifications make to the suspension geometry.
“It’s really important to install a control arm with geometry designed to match the changes made when raising the vehicle’s ride height. If you add a spacer or replace the strut, you change the ball joint angle, which was originally set at a specific degree – called zero gain – at static ride height. By raising the vehicle, the factory control arm will be at a different angle, adding significant stress to the ball joint. The factory bushings probably won’t be suited for this new angle, and the arms may move excessively under braking. That’s definitely not good, and it may prevent you from aligning the vehicle properly.”
To fix this, the suspension needs control arms designed to work with the other modifications. “You have a couple of options here,” Grigsby notes. “Many west coast-based manufacturers produce billet aluminum control arms with a Heim joint pivot on the frame side and a uniball pivot on the spindle side. These are great, but there are some things we’re not fans of with that approach.
“Uniballs are aircraft parts that made their way into the off-road world through race vehicles, and as we always say, race car parts make race car noises. If you live in an area where roads are salted or frequently encounter a lot of mud, this design might not be ideal. Also, because the control arm has two adjustable pivot points, aligning it can be a nightmare, and as the bearings wear, the alignment will shift.”
The next option is a tubular ball joint control arm, which typically uses a bushing pivot on the frame side. This allows you to rely on factory alignment adjusters to keep everything in spec, making it easier for a shop to perform proper alignment.
“There’s also a hybrid version that uses a bushing pivot at the frame and a uniball pivot on the spindle side. That’s a solid option, as long as you maintain it properly. But if you’re in an area with salted roads or debris that can corrode the nylon liner in that bushing, it’s probably not the best choice for you.”
Grigsby notes that both the billet aluminum and tubular control arm designs offered by ADS feature a heavy-duty ball joint – or uniball pivot – on the spindle side, with an O-ring-sealed top cap to prevent debris from getting inside and causing corrosion, along with a Delrin pivot bushing on the frame side.
“For weekend enthusiasts living in areas with inclement weather, I’d recommend the tubular ball joint-style arm. If you’re in an area with fewer environmental concerns, the aluminum uniball design is the best way to go.”
Now that we've lifted the truck and corrected the geometry of the upper control arms, we still have the factory sway bar and end links to deal with. Since the positions of other suspension components have changed, the behavior of the factory sway bar will change as well.
“The factory sway bar end link is now in the wrong position, adding preload to the bar,” Grigsby tells us. “That heightened preload will stiffen the bar, negatively impacting ride quality, creating more oversteer, and limiting suspension travel.”
He outlines two approaches to resolve this issue: “The first option is to retain the factory sway bar end link and install a raised sway bar end link bracket. This bracket fits between the sway bar end link mating surface and the control arm or axle, depending on the application. Your other option is to use an adjustable sway bar end link kit, which allows you to tune the sway bar back to OE stiffness – or whatever stiffness you prefer – based on your lifted ride height.”
“It’s important to maintain the CV axle geometry on a four-wheel-drive vehicle with an independent front suspension,” Grigsby says. “We’ve lifted the vehicle, we’ve got the control arm back where it needs to be, the sway bar is in the right spot, but our CVs are basically sitting in a droop position. So, we need differential drop brackets. In the past, these brackets were included in many leveling kits because engineers understood their necessity. But what's puzzling is that we don't often see them included in kits nowadays. Will the vehicle be okay without them? Maybe for a while, but eventually, the CV boot will tear because it's operating at an unfavorable angle, and the CV axle will wear out quickly.”
This trend has been a boon for CV axle suppliers, and enthusiasts who are unaware of the long-term effects have been paying the price. Fortunately, a simple drop-down bracket kit is all it takes to resolve the issue.
“It’s just a spacer that fits between the front differential mount and the differential itself, bringing it back in line. This will extend the life of both the CV boot and axle, while also allowing the CV’s articulation to match the additional wheel travel gained from installing coil-overs and control arms.”
“The factory outer tie rod ends are grossly undersized on many trucks and SUVs with independent front suspensions,” Grigsby points out. “GM is actually the biggest offender – the outer tie rod ball joint on a modern 3500 4x4 Dually is smaller than what you'd find on a Ford Ranger from the early ‘90s. It’s also a common problem with the modern Ford Bronco; the factory tie rods often self-destruct, even when you simply move to a larger wheel and tire package.”
As with other hardware we’ve discussed, using components designed for the vehicle’s ride height is crucial. Otherwise, components will be placed in positions for which they weren't designed.
In the case of this lifted vehicle, the factory tie rod end ball joint will operate at a severe angle, negatively affecting its longevity and introducing noticeable bump steer on the street.
As you might expect, the solution is to use a tie rod end designed for the task. “You’re looking for a tie rod end made from stronger materials like machined aluminum or forged steel, with a design that corrects the steering geometry. This will prevent the tie rods from sitting at extreme angles, resolving the bump steer issue and allowing full suspension articulation without overloading the ball joint, which could cause the tie rod to break.”
Grigsby notes that in applications like GM full-sized trucks, where a conventional steering box, idler arm, and pitman arm are used, the idler arms tend to be a common point of failure when larger aftermarket wheels and tires are added. These modifications introduce greater load spikes into the suspension due to the additional weight.
“When idler arms start to fail, you’ll notice bump steer and other abnormal feedback from the steering wheel while driving. The front end will shimmy when you hit bumps, and you’ll feel that through the steering wheel as the pitman arm tries to keep the truck going straight. A failing idler arm can be a serious hassle, so I recommend using one of the many bracing kits available to reinforce these pivots.”
“I can’t tell you how many vehicles I’ve seen with all of the modifications mentioned above, but the suspension still isn’t optimized because the OE bump stops are still installed,” Grigsby says. “This limits both jounce and droop.”
To fully benefit from your modifications, bump stops need to be tailored to your upgraded suspension setup at both ends of their travel. “There are pre-set, direct bolt-in bump stop kits available that make things easy because the work has already been done for you.
In situations where no such kits apply, you’ll need to cycle the suspension from full droop to full compression while keeping your intended tire size in mind, ensuring nothing contacts the inner fender well. You also don’t want the shock to bottom out completely, and it's important to avoid overextending the CV axle.
On the compression side, the general rule is to have one inch of shock shaft extended at full compression for a hydraulic bump stop. At our shop, we prefer about half an inch. Some folks prefer it completely bottomed out, but in those cases, you risk transferring the load from the shock into the chassis via the upper strut mount if anything moves in the suspension.”
While the front suspension has been our focus here, the rear setup can also be problematic. Grigsby points to pinion and driveline angles as common sources of trouble at the back end of the vehicle.
“One issue we see often with leaf spring trucks is when a lifted spring is installed, but the manufacturer didn’t include a degree wedge on the spring. This misaligns the pinion angle, causing vibrations, excessive wear on U-joints, and potentially even premature transmission failure, depending on the angle of the driveline.”
If you determine that the pinion angle is off, the solution is straightforward. “There are wedge kits that use the leaf spring center pin to center the wedge, with the wedge having its own pin that sits on the axle seat. These come in various degrees, allowing you to correct the angle for your specific application. Just subtract the amount the pinion angle is off from the correct pinion angle, and the result is the degree wedge you’ll need to use.”
If your vehicle has a two-piece driveline and the pinion angle is correct, but the driveshaft is still in an extreme position, installing a carrier bearing drop bracket will bring everything back in line.
Beyond these specific issues, Grigsby stresses the importance of regular maintenance and addressing potential concerns early.
“Pay attention to how the vehicle sounds and handles – don’t just roll up the windows and crank the stereo if something seems off. It may seem obvious, but it’s one of the best ways to catch small problems before they become big ones.”
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