Mercedes G 63 AMG 6x6 in Dubai 2013 84 Photos Zoom

Mercedes G 63 AMG 6x6: The monster, in detail

The brutal Benz is the world's most expensive series-produced off-road car. We explain the technology behind the huge, three-axle pick-up in detail.

This Mercedes G makes an impression. Beside the more than two metres tall and almost six metres long 6x6 monster a standard G looks as if it has been washed on too hot a setting. Anyone who can afford the three-axle monster will get one. Of course, it is not a matter of mere pocket money: the Swabians add more than 300,000 Euros to the base price of the G 63 AMG (138,635 Euros).

The invoice will come to 451,010 Euro when a handmade Mercedes G 63 AMG 6x6 is delivered. A this price, the three-axle monster replaces the previous record-holder as the most expensive Benz in the range: the SLS AMG Electric Drive costs "just" 416,500 Euros.

Mercedes G 63 AMG 6x6 – modular system

You can tell from our road test how brutish the 537 HP three-axle monster feels. At this point we want to have a look behind the scenes, explain the technology and delve a little deeper into the material than was actually possible in the road test.

With the G 63 AMG 6x6 Mercedes is in the fortunate position of practically being able to simply lift a design off the shelf. Of course, prior to the presentation of the prototypes, a huge amount of testing and tuning work had to be performed. But those who know their stuff will no that this is only a matter of bringing together what has belonged together for a long time.

Put simply, the Mercedes G 63 AMG 6x6 is the symbiosis of a military chassis, with the structure of the civilian 463 series, finished with parts from the accessories collection. The three-axle chassis originates from an order placed by the Australian army, requesting 2,000 Military G in the 6x6 design. Once the development was complete, Mercedes swiftly completed the "child's play" of releasing a left-hand drive 6x6-G, which also appeals to other military organisations.

This chassis from the 461 utility vehicle series serves as the backbone for the Mercedes G 63 AMG 6x6. It was combined with the civilian drive technology from the most recent model: the 5.5-litre biturbo V8 from in-house tuning division AMG, mounted onto the AMG Speedshift 7-G Tronic automatic transmission.

Specially manufactured body

It wasn't quite so simple to clothe the six-wheel drive powerhouse. The military version with its wide vegetable truck flatbed doesn't offer much in terms of "luxury", while the civilian 463 series has no pickup. Here the bodywork technicians had to work overtime to conjure a dual cab pickup from the long G-Class with its C-pillar support. The result is thoroughly harmonious. The loading surface continues the body shape of the long Mercedes G Station down to the bottom half of the vehicle, as if cast from a single die. 

G 63 AMG 6x6: more air!

In off-road vehicles there is generally only way to achieve greater ground clearance beneath the axles: bigger tyres. The raising of the chassis or body lift kits for ladder-frame vehicles do raise the frame and therefore the body, but do nothing to alter the clearance of the differential – the lowest point on the vehicle in the case of rigid-axle vehicles – from the ground. Portal axles, on the other hand, are a rare, but extremely technically interesting variant. This refers to axles whereby wheel transmission mechanisms are mounted to the axle casings. Military vehicles, for example from Volvo or Hummer, used this technology, however, portal axles have been used in civilian vehicles for decades, in the Unimog.

In the G 63 AMG 6x6 Mercedes combined both raising methods. So-called bolt-on portals are used: these are wheel transmission mechanisms that are flange-mounted onto standard rigid axles. Upgradable portal transmissions such as this are available from tuners for various vehicles , for example for Land Rovers, Toyotas or Jeeps. The hugely expensive wheel transmission mechanism fitting kits cost between 10-20,000 Euros on the open market – and as well as providing a structural increase in ground clearance, they also provide another positive effect: by redirecting the drive via the integrated gear drive, the axle ratio is shortened, by a factor of 1:1.27 in the case of the portals used by Mercedes. As a result of this shorter ratio, the considerably larger roll circumference of the huge tyres – Pro-Comp Extreme A/T in the 37x12.5R18 size are used - is by and large compensated for.

Springs from the G tank

Another advantage of the portal axles: the connection point of the axles, the chassis geometry and the angle of articulation of the cardan shaft are unchanged from the series model, which, in contrast with traditional raised chassis' offers advantages with regard to wear, handling and drive safety. In total, the portals and the huge tyres increase the ground clearance beneath the differential from the standard 21 to a very generous 46 centimetres. As a result of the huge height increase, the slope angles to the front and back are also dramatically improved (52/54 degrees) compared to the series version of the Mercedes G. And the Mercedes G 63 AMG 6x6 can also dive like a truck: it is approved for a wading depth of one metre.

For the chassis, Mercedes reached to the shelf holding the springs for the heavy, armoured special protection versions of the G-Class. The bullet-proof G-models are in a similar weight class to the Mercedes G 63 AMG 6x6, which weighs in at an unladen weight of 3.85 tonnes. The damping is taken care of by Öhlins dampers with external reservoirs, originally designed for use in motor sports.

To make this work in a car that appeals primarily to rich desert dwellers, the developers also dedicated themselves tirelessly to ensuring the Mercedes G 63 AMG 6x6's ability to drive on sand. In order to be able to switch quickly between the normal road-use tyre pressure and the extremely low pressure for journeys on deep sand, a tyre pressure system is installed as commonly found in Rally Raid. There are supply lines to the rims integrated into the axle portals, and while driving, a compressor fills a total of four 20-litre reserve tanks with compressed air. This not only means that the tyre pressure can be reduced at the touch of a button, but pumped up again to road-use level in record time. The driver has to do nothing, except press on two buttons in the cockpit. Manometers display the pressure in each case.

Mercedes G 63 AMG 6x6 – desert king

In order to drive in the sand with the lowest of air pressure, which creates a greater contact area, the tyres of the Mercedes G 63 AMG 6x6 are mounted onto Beadlock rims. With this rim design, the sides of the tyres are pressed against the actual rim by a screwed supporting ring and therefore cannot turn on the rim, even with the lowest air pressure. This makes it possible to drive on extremely deep sand, even with tyre pressures of just 0.2 bar.

The drive for the third axle of the Mercedes G 63 AMG 6x6 is cleverly realised. In the differential of the foremost rear axle, a chain controlled down thrust system from the differential housing is integrated, to which the second rear axle is flange-mounted by means of a cardan shaft. The Mercedes G 63 AMG 6x6 features a total of five locks, which, in accordance with the standard Mercedes G operating logic, is actuated via three toggle switches: with the first switch, the locks of the distributor transmission and the down thrust at the second rear axle are applied. Switch two locks the pair of differentials at the rear axles, and finally, the front axle can also be locked. As a result, the forward thrust is very similar to that of a track vehicle.

The fact that the 537 HP, with a live weight of around four tonnes are not without a price should be clear. Erring on the side of caution, Mercedes declines to provide a specification. It certainly won't manage any less than 30 litres per 100 kilometres, which is also demonstrated in the fact that it is equipped with a reserve tank. Together with the standard tank, the Mercedes G 63 AMG 6x6 has a fuel reservoir with a capacity of around 160 litres. Given the consumption during off-road use, in particular when driving on deep sand, normal citizens comparing the prices at German fuelling stations down to the last cent will be passing out anyway.

Autorenbild Torsten Seibt





10 April 2015
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