With the new Mercedes G-Class ditching the solid front axle it’s had since the late 1970s, the Jeep Wrangler is the only remaining high-volume SUV in the U.S. with a solid front axle. And while Mercedes claims the new Geländewagen was built to be great off-road, this is kind of a shame. Here’s why.
Admittedly, people who buy a modern G-Class aren’t likely to smash their $150,000 SUV through the Rubicon Trail. Still, this upcoming independent front suspension-having generation of G-Wagen represents yet another step in the demise of the solid axle setup, which is considered by many the go-to design for hardcore off-roading.
To be sure, the benefits of independent front suspension are numerous: ride quality and handling are much better in almost all driving conditions outside of smooth, straight highway cruising. Plus, independent front suspension allows for a rack and pinion steering setup, which is considered significantly sharper than an old recirculating-ball design. On top of that, recirculating ball designs tend to be hydraulic (which is less efficient than pure electric power steering), and there are some aerodynamic drawbacks to having two giant metal tubes running the width of the vehicle.
So it’s clear, based on the industry’s shift towards IFS, that automakers care more about fuel economy, dynamics, steering feel and ride comfort than outright off-road capability; considering how few people take SUVs to their off-road limits, this choice makes a lot of sense.
But there’s a reason why most rigs you’ll see crawling up boulders in Moab or traversing the Rubicon Trail have two solid axles underneath them: especially on production vehicles, solid axles tend to be tougher (halfshafts are protected by a thick steel tube, for example), and provide better wheel articulation (called “flex”) to keep all tires gripping the surface.
To be sure, trophy trucks and other purpose-built Baja racers have very robust, flexy independent suspension designs. And for sand and mud, IFS can actually be better than a solid-axle setup. But as far as production vehicles traversing a variety of uneven terrains—especially rocks—the best options throughout the years have had solid axles.
I recently drove the new Jeep Wrangler, and the way it was able to cover uneven terrain was night-and-day smoother than the Jeep Compass I drove last year, or even the new Toyota Tacoma I drove off-road the year before. The amount of wheel articulation, and the way the vehicle would stay balanced as one tire pushed up into the wheel-well and forced the other tire into rebound, made for better grip and a much less “tippy” ride.
As you can see in the photos above, the Jeep Compass teetered and lifted its tires off the ground when going over only moderately uneven terrain, making me nervous behind the wheel. The Tacoma did a lot better at keeping the tires planted thanks to the flexy solid axle out back, but the IFS up front made the truck roll quite a bit on the trails.
By contrast, here’s my solid-axle Jeep Cherokee crawling up a rock while the body is fairly level, and all four tires remain planted on the terra firma:
Between the articulation, robustness, and the fact that putting a lift kit on a vehicle with solid axles tends to be much simpler than lifting an IFS-equipped rig, solid axle-equipped vehicles have gained a cult following in the off-road world. But now, it seems, the only options left are the Jeep Wrangler and heavy-duty pickups, the latter of which are too big to be formidable off-roaders.
To be clear, I’m not writing the new G-Class off because of this; it looks like a compelling SUV, and I have no doubt Mercedes’ engineers built to be extremely capable. And it’ll be interesting to see which direction Land Rover goes with the new Defender, and whether Ford decides to go with a solid axle on its new Bronco.
I’d be surprised if either of them had the gall to make all the sacrifices associated with a solid front axle, and to actually put their money on pure off-road capability and the robust image that comes with it.
Then again, that strategy seems to be working out for the Jeep Wrangler. Somehow.