Why The Jeep Wrangler Needs To Ditch Its Solid Front Axle (2024)

Solid front axles (SFAs) are known to be effective off-road, boasting extreme wheel articulation. They are also reliable, easy to maintain, cheap to manufacture, and easier to modify. Yet Jeep is practically the only automaker left selling SUVs from the factory with a solid front axle. Most modern pickup trucks also come with independent front suspension. While solid front axles continue to serve a purpose in trucks and commercial vehicles, they have all but been eliminated from mainstream SUVs thanks to independent front suspension (IFS). There is a major culprit to blame for its demise: the death wobble. But what is death wobble, and why does Jeep insist on fitting one of America's favorite off-roaders - the Jeep Wrangler - with outdated and potentially flawed front suspension?

2024 Jeep Wrangler

7.9/10

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Make

Jeep

Model

Wrangler

Base MSRP

$31,995

Horsepower

285 hp

The Disadvantages Outweigh The Advantages For Most Buyers

A solid front axle consists of a solid bar (the axle) with a wheel at each end. It can pivot in the middle, which means that if the car is suspended in midair and one wheel is pushed up, the opposite wheel gets pushed down. Rather than being isolated from the wheel on the other side, what affects one also affects the other. This quality of the SFA is both an advantage and a disadvantage, but the design is not an accident.

It was a solution in part to keep the wheels parallel (with no big changes in the camber) and to work better when there are high roll centers involved. A roll center is the axis around which the car will roll (lean) and is higher in SUVs and off-roaders. A higher roll center is easier to manage with a solid axle, and this was especially true before the wide adoption of anti-roll bars for cars with independent suspension. Cars with anti-roll bars removed will roll much more and allow more opportunity for the wheels to change their camber, or 'tuck' under the car, when higher forces are involved.

The Advantages Of A Solid Front Axle

• Good wheel articulation
• Lower cost of production, cheap to repair
• Overall simplicity
• Robustness / Reliability
• Relatively easy to modify

It isn't just wheel articulation that favors solid front axles, although it's usually the main attraction for off-roading. Aside from looking cool (especially when the front/rear axles are at opposite angles), the solid front axle design allows the front wheels a better chance of making constant contact with the surface it is traveling over, which is better for traction, control, and stability. If a vehicle with IFS loses contact with the ground through one wheel, it will dangle precariously since there is no pivot point to push the wheel down and the suspension springs won't go that far.

Any torque going to that wheel will be lost and won't help the vehicle to move. There are more reasons why off-road enthusiasts still prefer the SFA - it is a proven, reliable, and durable part. It can be repaired and changed relatively easily since there are few parts. It is also easier to raise the ride height of this kind of system than cars with IFS, since those vehicles can necessitate more modifications to avoid damage when lifting a car with IFS, and not adapting other components can result in extra stress or damage to other parts.

Disadvantages Of A Solid Front Axle

• 'Death wobble'
• Jittery and reduced on-road comfort
• Inferior handling dynamics

As we can see in the video above, death wobble is no laughing matter. Since the wheels are connected on a common axis, what happens to one tire affects the wheel on the opposite side. Small bumps and vibrations get transmitted across the axle and shake the whole unit. This is one of the causes of death wobble. Despite its name, the phenomenon hasn't resulted in confirmed deaths but is a safety issue, resulting in severe shaking of the front end of the vehicle, violent steering wheel shimmy, and vibration/wobbling wheels.

Once started, this mechanical resonance can often be eliminated by simply slowing down. It affects cars with solid axles and can be made worse by worn components and high speeds. On-road comfort, high-speed stability, and sharp handling dynamics are not hallmarks of the SFA design. It is designed for lower speeds, challenging terrain, and industrial applications where durability is key.

An Independent Suspension Setup Is Just As Good

Unlike the SFA, IFS allows the front wheels to be fully independent of each other when encountering vibrations and changes in the terrain. One bump won't necessarily affect the opposite wheel, and its vibration is absorbed by the shock absorber. At high speeds, the phenomenon known as death wobble is eliminated, and the car also handles better. Independent front suspension trades the wheel articulation and inherent strength of the solid front axle for an on-road ride that is far superior. This is why most cars - especially performance cars - utilize independent suspension.

Since industrial vehicles and trucks are more focused on durability or challenging terrain, this on-road comfort, high-speed stability, and the requirement for sharp handling dynamics don't apply.

Such is the ability of modern IFS that off-roading utility vehicles like the Ford Bronco and Mercedes G-Wagon swapped out their SFAs for IFS. They are, for the most part, just as capable aside from hardcore off-roading trails. Modern features allow the IFS system to hold up to most of the off-roading that typical drivers will normally encounter.

Cars can also be fitted with an SFA for more serious off-roading, but automakers have found other ways to temporarily improve a car's off-roading characteristics -even with IFS. Ford's Bronco has a disconnecting anti-roll bar offered with some trims, such as the Badlands model. It comes with the Off-Road Hero Switch Pack, which allows the car to electrically disconnect the anti-roll bar and increase the front wheels' articulation. It works below 20 mph and automatically reconnects above that speed.

Independent Front Suspension Could Improve The Wrangler

The Jeep Wrangler continues to shine and remain an off-roading favorite for various reasons, not just its SFA. Its durable and proven design, styling, available 6.4-liter V8 engine, a wide array of configurations, and a good supply of aftermarket modifications all help to make it the go-to choice for a wide variety of customers. It's also still the de facto choice for many off-roaders, who celebrate rather than denounce the SFA.

Jeep doesn't manufacture the Wrangler for superior on-road dynamics, and that's perhaps the reason why its trusty SFA has been a constant since the Wrangler's inception in the '80s. The Stellantis-owned brand knows its customers well. However, on-road dynamics and comfort are important, and as SUVs become the gold standard in the industry, the Wrangler could be left looking outdated, since many drivers who buy the Wrangler for its SUV style will not take the vehicle off-road. With IFS, the Wrangler could also do the following:

• Keep the SFA for a hardcore variant like the Rubicon, while the rest of the range uses an IFS setup
• Utilize a disconnecting anti-roll bar for better articulation when needed for the IFS variants

Otherwise, Jeep risks getting left behind in the SUV race while focusing on catering for the serious off-roaders. Other models in Jeep's catalog feature IFS, so there is no reason that the Wrangler couldn't get an upgrade to on-road dynamics worthy of an expensive SUV in 2024.