2013 Mercedes-Benz G63 AMG 6×6 Concept

Independent and neutral: the chassis

The chassis is largely based on the current production configuration, the only difference being that the helical springs and dampers have been adjusted to take account of the changed characteristics of the three-axle model. For the springs, too, the engineers were able to draw on the comprehensive array of “G” parts, which includes no less than 15 different spring rates. While the front axle takes over the reinforced springs from an armoured special-protection variant, the first rear axle has been given a significantly harder spring rate and the second rear axle a softer one. This set-up, together with the rally-proven, adjustable gas-pressure shock absorbers, results in a perfect symbiosis of sporty dynamism and composed comfort, on or off the road.

Macho outside – S-Class inside

Visually, the G63 AMG 6×6 pickup leaves no room for any doubt as to its true calling. The large tyres on the three axles, the huge ground clearance, the height of almost 2.30 metres and the width of some 2.10 metres as well as the clean-cut lines of the pickup immediately inspire respect. Like the G63 AMG and G65 AMG models before it, the super off-roader with its 5.87-metre-long body has the characteristic AMG brand face with the “twin blade” radiator grille. Other visual highlights include the use of elegant carbon fibre for the integrated LED light strips above the windscreen as well as for the large flared wheel arches while the rear load area section has a distinctive stainless-steel roll-over bar. The load area, which is lined with particularly tough and durable bamboo, can be accessed by means of a tailboard.

Sporty luxury, the hallmark of AMG, is the defining characteristic of the interior. The G63 AMG 6×6 welcomes its occupants aboard with an exclusive ambience of classic red or light brown designo leather with contrasting topstitching and attractive diamond-pattern quilting. The four electrically adjustable individual seats are heated and ventilated. The rear compartment is equipped with a special centre console while the roof liner and pillars are finished in an Alcantara® covering.The rear panel is trimmed in leather.

Graz is the centre of the “G” world

The two G63 AMG 6×6 vehicles which have been built to date were developed with Mercedes-Benz at the helm. The Graz-based Mercedes-Benz G-Class development department is the centre of competence for all “G” projects and is responsible for development and series support of the legendary cross-country vehicle. Furthermore, Graz in Austria has been the production site for all civilian and commercial G-Class vehicles since 1979. The response to the near-series show vehicle will determine if and when the Mercedes-Benz G63 AMG 6×6 enters small-series production.

6×6 Drive technology: Ideal partnership: Off-road high-performance technology and AMG power

A look at the key data of the Mercedes-Benz G63 AMG 6×6 makes it clear that this model’s off-road world begins at a point where anything less than a vehicle with caterpillar tracks would have to capitulate. Six driven wheels, an off-road low-range ratio in the transfer case, portal axles and five differential locks which can be engaged on the move are features which one seeks in vain in conventional off-road vehicles. Together, they ensure that the G63 AMG 6×6 has driving dynamics which are more than a match for the toughest terrain. As a result, the show vehicle is able to storm up the highest sand dunes with ease while sand tracks hold no fears thanks to its unshakable directional stability. Rocky terrain is negotiated with all the agility of a mountain goat; fording a river becomes almost child’s play thanks to the impressive fording capability. And anyone exploring the on-road performance is certain to be impressed by the catapult-like acceleration of this 3.85-tonne pickup.

Despite its unique drive technology, the show vehicle does not actually represent a new development in terms of technology. After 34 years of G-Class production, there is such a large array of “G” parts to draw on that the G63 AMG 6×6 uses almost exclusively series-production components under the skin. A case in point is the drive train: the AMG V8 engine, the AMG SPEEDSHIFT PLUS 7G-TRONIC automatic transmission and the front drive system have been taken over from the G63 AMG while the transfer case with low-range ratio has been matched with a rear twin drive train from a 6×6 version which has already proven its reliability in service with users such as the Australian army.

Technical highlight: the portal axles

Newly developed for a wide variety of applications, the portal axles which have been added to the Mercedes-Benz off-road portfolio are the real technical highlight of the show vehicle. Unlike conventional rigid axles, where the wheels are centred on the axis of the shaft, the wheels of the portal axle are significantly lower thanks to the portal gears on the axle heads. As a result, the ground clearance of the G63 AMG 6×6 is increased to 460 millimetres (series-production G-Class: 210 millimetres) and the fording depth – or maybe it would be more accurate to say diving depth – is increased to 1000 millimetres (series-production: 600 millimetres).

This design has further important benefits which do away with the need for elaborate adaptation measures. As the position of the axles relative to the chassis remains unchanged, so too do the suspension anchorage points, the steering connection and the position of the propshafts. Furthermore, the portal gear reduction ratio compensates for the huge rolling circumference of the 37-inch tyres so that the gear ratios, speedometer drive and ABS sensors also remain unchanged. An additional benefit of the reduction ratio applied by the portal gears is that the drive torque is only applied to the wheels themselves with the result that the mechanical loads on the drive train – especially the drive shafts – are reduced.

Through-drive: the centre differential

A technically sophisticated solution provides the 6×6 drive system with the necessary through-drive through the differential of the first rear axle to the rear one. The arrangement which has been developed is extremely compact and requires little more space than a conventional differential housing. An extra shaft with an integrated lock situated on the side above the differential takes the drive torque to the rear axle. A chain provides the necessary power take-off for the differential of the first rear axle.

Precisely coordinated logic governs operation of five differential locks

With a total of five mechanical 100-percent differential locks available, drivers would certainly lose track of the settings now and again if they could be engaged separately. This is why the engineers have developed a special locking logic which ensures the best possible traction is available in every situation. The whole system is controlled electrically with the usual three differential lock switches in the centre console which are to be found in all G models. Preselected and engaged locks are indicated by yellow and red lights respectively.

• Stage 1: the two inter-axle differential locks in the transfer case and in thethrough-drive through the centre differential are active
• Stage 2: the interwheel differential locks in the tworear axle differentials are additionally activated
• Stage 3: with the front axle differential locked, allfive differential locks are now active

All lock stages can be selected regardless of whether the low-range ratio in the transfer case is selected.

It is clear that, with a wheelbase of some 4.20 metres, the G63 AMG 6×6 is not predestined for virtuoso cornering. Nevertheless, in order to ensure impressive agility with corresponding dynamism about the vertical axis of the vehicle, the engineers have varied the torque distribution. The drive torque is therefore split 30 to 40 to 30 percent between the front axle and the two rear axles.

V8 biturbo from power specialists Mercedes AMG

Much of the credit for the superior performance of the Mercedes-Benz G63 AMG 6×6 is due to the AMG V8 engine and the AMG SPEEDSHIFT PLUS 7G-TRONIC automatic transmission. The AMG 5.5-litre V8 biturbo engine develops a peak output of 400 kW (544 hp) and 760 newton metres of torque. Known in-house by the designation M 157, the engine impresses with its technological highlights. The greater thermodynamic efficiency which results from the combination of twin turbochargers, direct petrol injection and spray-guided combustion allows better fuel economy and leads to lower exhaust emissions. Fast and precise piezo-electric injectors spray the fuel into the combustion chambers, ensuring a particularly fine distribution throughout the air in the combustion chamber. An electric low-pressure pump delivers the fuel from the tank to a high-pressure pump in the engine compartment at a pressure of six bar. The fuel pressure in the high-pressure rail is controlled between 100 and 200 bar on a fully variable and demand-related basis, ensuring an agile response in any driving situation. Further highlights of the innovative and unique eight-cylinder powerplant from AMG in Affalterbach include an all-aluminium crankcase, four valves per cylinder with camshaft adjustment, air/water intercooling and alternator management.

Any doubts about the show vehicle’s ability to speak directly to the emotions are quickly dispelled by a look at the AMG sports exhaust system: twin tailpipes ahead of the rear wheels on both sides put out the hallmark AMG eight-cylinder sound.

Faster shifting with the AMG SPEEDSHIFT PLUS 7G-TRONIC

Featuring three drive modes and an automatic double-declutching function for downshifting, the AMG SPEEDSHIFT PLUS 7G-TRONIC automatic transmission delivers the drive to the transfer case with low-range ratio by means of a propshaft. “Controlled Efficiency” (C) mode calls up engine and drive control strategies designed to deliver a driving style which is as economical as possible. In the Sport (S) and Manual (M) driving modes, the engine-transmission combination displays considerably greater agility. Here, a brief and exactly defined retardation of ignition and injection during upshifting at full load provides for shorter shift times. Furthermore, in “M” mode, the G63 AMG 6×6 maintains the gear selected by the driver to the extent that this is permitted by the engine rev limits – a particularly useful feature when negotiating challenging climbs.

The efficiency of the AMG SPEEDSHIFT PLUS 7G-TRONIC automatic transmission system is further enhanced with a new fuel economy converter with centrifugal pendulum, friction-reducing bearings and transmission oil thermal management.

It makes sense to provide an ample fuel supply for vehicles which are designed to be used in remote areas. This is why the standard production tank with a capacity of 96 litres has been complemented by a 63-litre auxiliary tank. The total tank capacity therefore amounts to 159 litres.

Chassis and wheels: Automotive declaration of independence

As already described, the chassis is largely based on the current production configuration, the only difference being that the helical springs and dampers have been adjusted to take account of the changed characteristics of the three-axle model. For the springs, too, the engineers were able to draw on the comprehensive array of “G” parts, which includes no less than 15 different spring rates. Both the front axle and the first rear axle have substantially harder springs from the special-protection variant while the second rear axle has a softer spring rate.

With all three rigid axles able to move independently, the Mercedes-Benz G63 AMG 6×6 has independent axle suspension rather than independent wheel suspension. The axles articulate independently of each other, thereby ensuring the best possible frictional connection with the ground at all times. Although the two rear axles are only 1100 millimetres apart (the overall wheelbase is 4220 millimetres), they are able to assume dramatically opposing articulation angles and so make effective use of every opportunity to gain traction, even in extremely rough terrain.

Only a “G” can improve on a “G”

The adjustable and rally-proven gas-pressure shock absorbers are supplied by an external partner. Working in concert with the voluminous tyres, the chassis set-up impresses with its outstanding ride comfort combined with high driving dynamics and driving safety under all conditions, on and off the road.

If, despite all the driver’s efforts and the outstanding ground clearance, the chassis should accidentally come into contact with the ground, the developers have had the foresight to equip the vehicle with a robust, three-part underguard in stainless steel. This ensures that the most important assemblies at the front and rear as well as those in the underbody area between the front and rear axles are well protected from impacts and hefty knocks.

“…and major variations in air pressure are expected to occur rapidly…”

The design of the tyre pressure control system is in keeping with the high technical standard of the G63 AMG 6×6. A system that is a familiar feature of many trucks is being used in a passenger car for the first time. From inside the vehicle, it is possible for the driver to adjust the tyre pressure on the front axle and both rear axles independently at any time by means of switches on a special overhead console. Pressure gauges allow the pressures to be monitored. This means that the occupants are spared the usual laborious process of getting out and adjusting the pressures manually. Thanks to a powerful compressor and four 20-litre compressed air reservoirs fitted at the sides in the rear wheel arches, the tyre pressure can be adjusted in possibly world-record time. For example, although there are six voluminous tyres with a diameter of one metre each, it takes the system under 20 seconds to increase the sand-friendly tyre pressure of 0.5 bar to the 1.8 bar required for on-road use. Conventional systems take around ten minutes to achieve such a change in tyre pressure.

The design of the portal axles also has a very positive effect where the tyre pressure control system is concerned. Unlike the situation found where conventional rigid axles are fitted, the inner faces of the wheel hubs are exposed and the installation space is not blocked by the drive shaft. This means that the tyre pressure adjustment can be carried out directly by means of a central channel in the wheel hub. The wheels also have an air channel and are connected to the hub via a compressed air hose with a quick-release coupling to enable a wheel change, if necessary. A strong, bolted hub cover protects the hose connector from damage in off-road terrain.

Despite a kerb weight of 3850 kg: Ground pressure distribution as low as a human footprint

With the usual wheel/tyre combinations it is impossible to reduce the tyre pressure to 0.5 bar for driving in sand. 1.0 bar is normally the lowest possible pressure, below which tyres may come off their rims during steering manoeuvres and sand can enter the sealing surface between tyre and rim, resulting in a slow puncture. There are no such problems with the G63 AMG 6×6 which is equipped with special, two-part 45.7 cm (18-inch) beadlock wheels. When a tyre is fitted to this type of wheel, it is clamped between the wheel (formed by the two halves of the rim) and an internal beadlock ring so securely that, even in the event of a complete loss of pressure, it cannot slip off the rim and sand cannot enter.

The extremely low tyre pressures increase the contact patches of the 37 x 12.5 x 18 inch all-terrain tyres and provide considerable support when it comes to making progress on loose surfaces. Two processes contribute to this. First, the increased contact patches reduce the ground pressure and thus the tendency of the tyres to sink or dig into the ground. A look at the figures brings this home: reducing the tyre pressure to 0.5 bar increases the contact patch threefold. As a result, the ground pressure of the G63 AMG 6×6 with a ready-to-drive kerb weight of 3850 kilograms is equal to that of the footprint of a person of average weight.

Second, on muddy and similar surfaces offering better contact, the low tyre pressure supports the self-cleaning process which prevents clogging of the tread pattern and so ensures that the best possible traction is always available.

Body, equipment and interior: Typical AMG: A full range of exclusive equipment and appointments

Visually, the Mercedes-Benz G63 AMG 6×6 leaves no room for any doubt as to its true calling. The large tyres on the three axles, the huge ground clearance, the inside height of almost 2.30 metres and the width of some 2.10 metres as well as the clean-cut lines of the pickup immediately inspire respect. Like the G63 AMG and G65 AMG models before it, the super off-roader with its 5.87-metre-long body has the characteristic AMG brand face: the “twin blade” radiator grille with its chrome-plated twin louvre and chrome-plated grille ensure that, like its series-production stablemates, the G63 AMG 6×6 is immediately identifiable as an AMG model. The design of the grille takes account of the classic G-Class form and fits into the overall look with its interpretation of the off-road character of the vehicle. The typical three large air intakes in the front AMG bumper allow the airflow to reach the cooling modules. Vertical stainless-steel inserts in high-gloss chrome underline the masculine look.

The side view shows that, up to the two rear doors, the body corresponds to the current production configuration of the four-wheel model. But that is as far as the common features go, as the side view also reveals the differences – from the significantly greater ride height to the carbon fibre of the integrated LED light strips above the windscreen to the flared wheel arches – also in carbon fibre – with the stainless-steel running boards. The series-production part of the body is extended harmoniously by a third side window and the pickup section with the stainless-steel roll-over bar as well as the rear, twin flared wheel arches in carbon fibre. The load area, which is lined with particularly tough and durable bamboo, can be accessed by means of a tailboard.

Off-road comfort with four individual seats

As well as featuring the series-production facelift measures, such as the new dashboard with the central colour screen, the G63 AMG 6×6 offers an AMG instrument cluster with a colour TFT screen, the AMG main menu and a separate gear indicator as well as AMG door sill panels illuminated in white at all doors. The high-quality E-SELECT lever with the embossed AMG emblem is familiar from vehicles such as the SLS AMG. An exclusive ambience is created by the designo leather appointments – in classic red or light brown – comprising not just the upholstery of the four individual seats, but also the entire lining of the front and rear doors. Contrasting topstitching and attractive diamond-pattern quilting provide the perfect complement to the appointments. Furthermore, the entire dashboard is finished in leather and also features the exclusive contrasting topstitching. AMG carbon fibre trim and the Alcantara® covering on the roof liner and pillars complete the luxurious and welcoming interior.The rear panel is trimmed in leather.

In addition to the full array of characteristic AMG luxury features from the Mercedes-Benz G63 AMG 6×6 and the comprehensive designo leather appointments with four individual seats, the show vehicle is provided with a package of exclusive extras. These include a set of special features for the rear of the occupant compartment: electrically adjustable, heated and ventilated individual seats, a separate centre console – also finished in designo leather with contrasting topstitching – and the Rear Seat Entertainment System with two colour screens on the back of the front head restraints. Diamond-pattern floor mats complete the line-up.

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