To the untrained eye, the new G-Class looks much the same as its predecessors. But don't be fooled by the newcomer's iconic silhouette: Mercedes-Benz has reinvented its mightiest off-roader. Our UK correspondent, Richard Lane, has driven the Mercedes-AMG G63 version of the G-Class (traditionally the range's top-selling derivative) and boldly declares ita "proper Range Rover rival".

Gunnar Guthenke, the head of Mercedes-Benz's G-Class division, suggests the people who buy this car fall into 3 categories. There are "true off-roaders", who, for either professional or recreational reasons, require a device capable of forging a path many would consider too challenging to undertake on foot. Then there are the aesthetes, who feel they can’t get a machine of such bravura anywhere else. The kindest way to describe the last group is "the new money"… this is the buying demographic that craves the most extravagant, bombastic creation to wear the Three-pointed Star. It’s a role that’s been comfortably filled since AMG began fettling the G-Class in 1999.

The car’s history goes back rather a lot further in time than that, of course. Having been introduced in 1979, the Graz-built G-Class is Mercedes’ longest-serving model, and it’s also the only one to have no specified "end of production" in the diary. What you see here represents the most significant upgrade the G-Class has undergone – one that aims to keep all 3 of the aforementioned cliques happy – and it’s no stretch to call it a "reinvention".

The G-Class is one of the most instantly recognisable vehicles on the road, underneath its aluminium sheetmetal, Benz has rung the changes.

However, the biggest problem in reinventing an icon lies in knowing what to keep and what to change. In this case, Mercedes has improved almost everything underneath the aluminium skin, but left the car’s demeanour well alone. It must have been tempting to increase the rake of the windscreen – less wind noise, more space for the vast digital dials embedded in the dashboard – but the change amounts to less than a single degree and so the fantastically elevated, abrupt view from the front seats remains.

Still looks old school – on purpose

Similarly, the hinges of the doors remain visible, and much of the opening and closing mechanism has been carried over so owners can continue to enjoy that richly mechanical crunch. That’s precisely the sort of thing that matters to so many of those prepared to hand over the best part of R1.7 million to get their hands on a new G-Class, let alone the AMG version. No surprise, then, that the bonnet-mounted indicators also remain, despite costing 5 times as much to develop as originally planned.

Although the G-Class interior is as luxurious as any premium SUV's, the driving position remains bolt-upright and on-top-of-the-dashboard.

Mercedes has safety regulations to thank for that. They stipulate that the housing must be deformable from any angle and the light emitted be visible from road level less than a metre from the front of the car. The front passengerstill has the convenience of a dash-mounted grab handle, although, this being 2018, it looks much smarter.

All occupants will also benefit from substantially more leg and shoulder room than before. Step from the oldW463-generation car into the new one and the growth spurt is palpable. In fact, the new car has grown inevery dimension, being 53 mm longer, 64 mm wider and 15 mm taller than before.

The new G-Class' increased dimensions makeits occupants feel less cramped. The quilted leather adds to a bespoke-cabin ambience.

The other fundamental change to the G-Class is found within the interior. The architecture retains an old-school feel, with its squared-off panels, but that’s juxtaposed against a pair of adjacent 12.3-inch displays. Various parts are borrowed from the E-Class but, for a hand-built car, it feels suitably opulent, not to mention comfortable.

There is little here to upset the design junkies, then (moreover, this car looks far more convincing in the metal than in the pictures), although it is the driver who stands to gain most from the wholesale changes Mercedes-Benz has wrought… With the help of a new brace that links the front suspension turrets, the torsional rigidity of the ladderframe and bodyshell has increased by more than half.

The fascia of the G-Class' cabin is a far cry from the '80s original; the milled metal finishes feel grand and look positively futuristic.

The G-Class has historically been guided by a low-geared recirculating ball set-up so infamously indirect that having only just turned the nose of the car in you’d need to begin unwinding the lock simply to avoid runningwide on the exit. Owners have long complained about this, so there’s now electromechanical rack and pinion steering.

New double-wishbone front suspension

Laying the foundations for such a change, Benz relinquished a rugged solid front axle in favour of using double wishbones mounted directly to the ladder frame. It has not been an easy job: to maintain the G-Class’tremendous ground clearance, the engineers had to position the lower wishboneattachment point as high as possible, fighting for every millimetre. Incidentally, ground clearance between the axles has increased by 6 mmto 241 mm (it continues to better that of a ToyotaLand Cruiser 200).

Even though the G-Class' on-road performance shows tremendous improvement, its off-road prowess is, incredibly, better too.

You could fill a book with this car’s off-road vital statistics – breakover angles, wading depth and so on – but suffice it to say that when going gets tough, the new G-Class is superior to its predecessor in every measurable way, if only by a small margin.

The 'brick' handles much better

By contrast, out on the road,it is quickly apparent that this car now possesses an attribute that has for decades evaded it entirely: handling. In addition to the modernised front axle, there’s a new rigid rear axle that’s placed by four trailing arms with the continued use of a Panhard rod to prevent any undesirable lateral movement.

The redesigned suspension and adaptive damping have made the G-Class much more sure-footed, body roll is well under control.

There is body roll and it can be substantial if you’re really working the Goodyear Eagle F1 rubber fitted to AMG models, but the roll rate is suitably commensurate with steering inputs, allowing you to work the contact points. Likewise, with such a high centre of gravity to fight against, it’s not long before the front tyres are chirping with understeer, but the remarkable thing is that you can accurately predict when that point will arrive and drive accordingly.

Play by its rules – be patient on corner entry – and you can get the G63 to adopt a satisfying rear-led balance as you knead more torque into the road surface. It’s old-fashioned (if slightly cantankerous) fun. This car is farcically quick; the decision to adjust the torque split from 50/50 to a rear-biased 60/40 hasn’t hurt the dynamics.

A "bewildering" 850 Nm is enough to create a mini sandstorm when applying full throttle in the loose stuff…

Adaptive suspension now standard

The ride quality has dramatically improved too. All G-Class models will use adaptive suspension, and although there’s still a consistent low-frequency jostle, it’s subtle enough that you might just consider this car as a long-range rival for a Range Rover or Porsche Cayenne. Barring the odd clunk from a differential and the wind noise at speed, usability and refinement are now a significant part of the G-Class package.

But let’s return to the subject of torque, because it’s remarkable that it has taken so long to get to the heart of the matter. In the case of the G63, that heart is Mercedes-AMG’s M178 4.0-litre twin-turbo V8. Tuned for duties in a 2.5-tonne off-roader, it develops 430 kW at 6 000 rpm and a bewildering 850 Nm at 2 500-3 500 rpm, making it more potent even than its dry-sumped sibling in the Mercedes-AMG GT R supercar. Top speed is 240 kph, but it is a 0-100 kphof 4.5sec that widens the eyes.

Again, the side-opening rear door is an anachronism in contemporary SUVs, but at least you can stack goods completely vertically.

The engine operates through a Mercedes 9G-Tronic torque-converter transmission with quite outstanding aural pomposity, and while not quite as serrated as the 5.5-litre M157 unit, its more hulking tone matches its predecessor for sheer volume. Cruise anywhere remotely near a parallel structure and there’s no doubt the exhausts exit to the sides, so for all itssophistication, this (at least in AMG guise) is still a machine those of a retiring disposition will tire of quickly.

Summary

With so much to take in, a full road test of this G-Class is certainly warranted, and we're unlikely to get a chance before the 4th quarter of 2018 (its South African launch is confirmed for late in Q3). What’s clear is that it’s a machine that has comprehensively redefined its bandwidth, while richly retaining its core character.

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