Sampling Mercedes' next midsize SUV
I was starting to get worried. No, it had nothing to do with the surprisingly difficult off-road trail our prototype 2020 Mercedes-Benz GLE 450 was crawling over. We’ll get to that, but suffice to say, the GLE handled it fine. My concern was that I couldn’t find anything wrong with the GLE, even this camo’d-up development mule.
Times like these are when my journalism professors start haunting me. Am I not being critical enough? Not paying close enough attention? No car is perfect, and very few come close. Was this one of them, or was I missing something? I focus harder, looking, listening, and feeling for faults.
I come up empty-handed.
The new GLE-Class really is that good, even in prototype form.
It starts with an all-new platform called Mercedes High Architecture, or MHA, but not necessarily all-new ideas. Indeed, the big party trick was born out of the road-only S-Class. Mercedes is calling it E-Active Body Control, and it takes the S-Class technology a big step further. On the S, a forward-looking camera scans the roads for bumps, holes, wavy pavement, and more and adjusts the damping so that when the car arrives at the obstacle it can waft over the imperfection without disturbing the passengers. It does so using hydraulics to lift the wheels up to pop over a bump or push them down into a hole, then put them back where they belong as you come off the bump or out of the hole. In practice, it allows you to drive over a speed bump at 35 mph (56 km/h) and barely notice it.
The new GLE advances this idea by replacing the S-Class’ central hydraulic system with individual, independent hydraulic systems at each wheel, allowing the computer to control each wheel separately from the other three and fine-tune the damping on a level even the mighty S can’t touch. Donut-shaped hydraulic accumulators fit around the dampers, and high-powered servos adjust the preload and rebound constantly to iron out the road. As an added bonus, the system is powerful enough that Mercedes engineers were able to get rid of the physical anti-roll bars and rely instead on the hydraulics.
Our well-appointed prototypes were fitted with both the fancy dampers and the optional air suspension (steel springs and fixed dampers are standard), which in most cases would’ve been handicapped by the also-fitted sport package with enormous 21-inch wheels staggered 275 and 315 front/rear in Pirelli P Zero SUV performance tires with skinny 45- and 40-section sidewalls. Instead, this big SUV rode like, well, an S-Class. Undulating pavement ceased to exist as the system kept the ride perfectly flat, while potholes and railroad tracks were reduced to small bumps, more noise than impact.
To truly appreciate how well it rode, though, I had to get out and ride in a current-generation GLE 43 AMG Coupe that was tailing us. Suddenly, the highways and byways around Birmingham, Alabama’s Barber Motorsports Park felt coarse, wavy, and seemed to have much bigger expansion joints, potholes, and bumps. The GLE prototype had simply been erasing them all.
I mentioned that E-Active Body Control does away with physical anti-roll bars, and it’s more than a technical curiosity. Among other things, it allowed the GLE engineers to crib another high-end Benz trick: Curve Control. Originally designed for the SL-Class, Curve Control lifts the suspension on the side of the car opposite the direction of the curve it’s taking (you turn left, it raises the right side of the car). This helps reduce some of the lateral g force on the passengers as you corner. On the SL, the system felt very abrupt, like the sudden banking of a roller coaster. As you turned, there was a push from the side of the car and you were jacked up on an angle.
The GLE engineers have thoughtfully refined the system to the point where it’s effectively invisible in normal driving. There’s still a hint of that abruptness in its maximum setting (Lean Level 3) at low speeds, but now that you can adjust the amount of lean, you can dial it back to your liking. Or you can simply choose another driving mode like Comfort or Sport if you don’t care for it or don’t need it. In especially sharp corners or emergency maneuvers, the computer temporarily and automatically cancels Curve Control until things settle down.
Road scanning is only active in Comfort and Curve Control driving modes, but don’t think everything goes to pot if you select one of the sport or off-road modes. The computer simply relies on individual wheel sensors, yaw sensors, steering angle, throttle/brake position, and more to continuously vary the damping rate for the conditions.
The sport modes are where E-Active Body Control’s virtual anti-roll bars really shine. Keeping any vehicle’s body flat in a corner is a task, and it only gets harder as the vehicle gets taller and heavier and the center of gravity rises. Make no mistake, the new GLE is a big SUV, but it corners flatter than your average sporty sedan. When a typical vehicle goes around a corner quickly, there’s both a lateral and vertical component to the body roll. Depending on which side of the car you’re on, you move slightly up or down as the vehicle leans in addition to feeling pulled to the side. The GLE eliminates that vertical motion, so all you feel is the sideways pull. At most, there’s a slight dip at the corner with the most weight on it, the outside front then rear as you enter and exit a curve.
With that kind of body control and an impressive level of grip afforded by the steamroller-spec Pirellis, our GLE prototypes handled shockingly well considering both their size and mass and the fact they weren’t AMG products but simple GLE 450s with a sport package. In most corners, it’s just grip and go. You can’t really attack sharp corners without getting a moderate understeer, but that’s to be expected. What’s unexpected is the amount of rotation the stability control allows in Sport+ mode when you power out of the corners. It’s like the GLE engineers knew there was nothing they could do about the front end but wanted to make up for it by loosening the reins on the rear end just a little. It does all this by stiffening the virtual rear anti-roll bar during sporty driving, though it will go back to stiffening the virtual front bar when speeds get high to promote stability.
Helping achieve all this is Mercedes’ new 3.0-liter turbocharged inline-six with assistance from an electric motor between it and the transmission. In addition to the natural smoothness of an I-6, this engine boasts seamless torque thanks to the electric assist and a unique and pleasing growl that’s throatier than your typical I-6. It’s matched to a nine-speed automatic and a standard 4Matic all-wheel-drive system that utilizes a new electronically controlled wet-clutch center differential that can send 100 percent of power to the rear and up to 65 percent of power to the front on pavement. Left-to-right torque distribution is handled by the brakes as both differentials are open.
Off-road, though, is where the real surprises show up. Here, the Benz engineers pull out the entire bag of tricks. On the dirt, the air suspension can raise to the highest of its six settings, 3.1 inches higher than normal ride height (it can also drop 1.6 inches below normal for easy entry and exit), the center differential can fully lock and send 100 percent of the power to the front axle if it needs to, and the optional two-speed transfer case can be dropped into its crawl ratio.
Don’t think the system gets dumb, though. Every sensor but the road-scanning camera is still active, and the damping is being adjusted constantly to deal with the terrain. To keep you out of trouble, low range and maximum ride height are a package deal and come with an electronic speed limiter of just 12 mph (19 km/h). The center diff, meanwhile, is constantly varying the front-rear torque split and fully unlocks when you’ve got the steering wheel turned to the stops to improve the turning radius.
With a set of optional Pirelli Scorpion ATR A/T M+S in a square 275/50R20 fitted on all corners and steel plates fitted under the engine and transmission/transfer case, the big GLE becomes a rounder, plusher G-Wagen off-road. On a moderately difficult trail, the GLE crawled over decent-sized rocks, forded deep water, dropped into crevasses, and climbed up and down very steep hills without missing a beat or dragging a bumper. I saw an indicated 45 degrees of downward pitch and 28 degrees of roll on various obstacles. We even backed up that 45-degree slope, just for fun.
You might think those open differentials would be a deal-breaker off-road, but like many modern SUVs, the GLE gets away with using the brakes as a limited-slip differential. Unlike many others I’ve tested, though, the GLE’s computer clamped down on a tractionless wheel in less than half a rotation and sent power to the other side, where others would’ve let the wheel spin a bit before realizing it had no grip.
What’s really remarkable about the GLE’s off-road performance isn’t the kind of situations it can get itself into and out of; it’s how easy it feels from inside. Coincidentally, I’d pre-run a Jeep trail the previous weekend in our long-term F-150 Lariat FX4 and the difference in passenger comfort was shocking. In the pickup, I was constantly being thrown violently from side to side in the front passenger seat as we traversed rocks, roots, bumps, and holes. In the GLE, in the same seat on a more difficult trail, I spent the entire ride taking notes on my phone and never once reached for a grab handle. The level of body control on the Benz is that good.
Then there’s the fun stuff. Dig deep enough into the off-road menus, and you’ll find a screen that allows you to control the height of each wheel independently with sliders. Ever watched a video of lowriders dancing on their hydraulics? It’s basically like that, if a bit less dramatic. Then there’s Free Driving Mode. It’s meant to keep you from getting stuck in deep sand, and it does that by making the car hop straight up and down surprisingly hard. The idea is to unload the tires slightly and let the sand get under them rather than pile up in front and cause you to dig a hole. I guarantee both of these features will be used to show off on pavement at some point.
I’d like to tell you even more about the new GLE if you’re still reading, but the terms of my access to these prototypes forbid it. What I can tell you about is what you can see if you look closely enough at the photos. Right away you’ll see the new car adopts Mercedes’ twin-eyebrow LED daytime running lights. Look closer and you can see that beneath the camo the dramatically sloping C-pillar—a calling card going back to the first ML-Class from which the GLE-Class came—is still there. Cast your eye down to the wheel arches, especially at the rear, and you’ll see the GLE has very wide hips to accommodate its massive tires. In all, it looks like a tall, beefcake E-Class wagon with a shorter rear overhang. Step back and you appreciate how well Mercedes’ designers and engineers have nailed the proportions.
Given its performance on-road and off, it should be easy to see why I was second-guessing myself. You just don’t expect this breadth of capability from a luxury SUV, or even a mainstream one. Few modern SUVs do this much, period, and fewer do it this well. I’m sure it’s got faults somewhere, and I’m looking forward to trying to find them when production models hit the road in the first half of next year as 2020 models.