‘Skunkworks’ co-op with AMG improved G-Class breed
BY BYRON MATHIOUDAKIS | 7th May 2018
Developed over just four years, a “near-record” according to Daimler AG G-Class development head, Oliver Metzger, the new ‘Geländewagen’ was overseen by about 250 people based at Magna Steyr in Austria.
There are usually more than 4000 people who normally look after Mercedes-Benz vehicle development at Sindelfingen. Magna, which also builds E-Class 4Matic all-wheel drive, has built all G-Classes since the series was released in 1979.
“A big challenge was that we have such a small team working on the Geländewagen,” Mr Metzger gold GoAuto at the international launch in France late last month. “But there is lots of passion among us all and everybody had a very clear vision of what we wanted to have.” With more than 300,000km of “high fatigue” off-road testing, prototypes underwent extensive and punishing hot-weather shake downs in Death Valley in the US, Spain and Morocco, as well as winter tests in Sweden and Germany.
Mercedes-AMG was instrumental in pushing for double wishbone suspension up front and a five-link solid rear axle – replacing the outgoing model’s MacPherson struts and leaf spring set-up – to meet performance and dynamic targets.
While a three-link design for the rear was originally confirmed until sometime into its development, the team realised that the rear could not match the front suspension’s on-road performance capabilities.
Mr Metzger also revealed that a number of other suspension systems – including air suspension – were also discussed, but were dropped on cost or complexity grounds.
“Air suspension was briefly considered but the idea was discarded,” he said. “For it to even approach our off-road goals the airbags had to be inflated to a very hard level, which was not comfortable enough,” he said.
The newcomer’s centre of gravity is a little higher than before, given the rear end has been raised slightly for greater ground clearance, now rated at 270mm.
Off-road benchmarks included the Toyota HiLux and Volkswagen Amarok, while the Bentley Bentayga and Infiniti QX80/Nissan Patrol served as the surprising yardsticks for on-road comfort and control. Also name checked was the Range Rover and new Land Rover Discovery for premium interior feel, quality and overall presentation.
Also new to the G-Class is an electromechanical rack and pinion steering system, which has a far lower ratio than the previous hydraulic recirculating ball item. It is shared with the upcoming next-generation GLE SUV out next year.
Mr Metzger said that as Daimler management insisted on retaining a mudguard-sited indicator position, his team had to develop a way that these could pass pedestrian impact legislation, as they can pose threats of serious injury.
The solution is a novel breakaway system that disintegrates on that sort of impact but keeps its integrity in the rough and tumble of everyday situations such as car washes.
Another challenge was the desired, distinctive ‘clang’ when the doors shut – an easy enough thing to achieve with the previous steel items, but something of “a headache” with the switch to the lighter aluminium items (as part of a 170kg weight reduction).
“It took many months of development to achieve the desired sound,” Mr Metzger admitted. “But it is seen as very important to sound like the original G-Class… this is what the research has shown.” As with the preceding version, about 100 are set to be made each day, and while the manufacturing process has eased with advances such as a single-piece rather than three- piece side panel stamping (which has the benefit of also adding stiffness and cutting noise path transmission as well as controlling quality), much of the vehicle still takes the same amount of time to put together. There are no robots on the Graz production line.
Triple seals now feature around some of the door and tailgate apertures, although not on all as originally intended due to cost and complexity constraints, after it was discovered that the singles and doubles met noise targets where applied.
The G-Class’ 170kg cull also came from a substantial increase in the use of high and ultra-high strength steels, however Daimler management’s originally stated target of “an unreasonable” 400kg weight drop was seen as achievable but at too much of a compromise to the quality, off-road ability and refinement benchmarks, considering the capability bandwidth demanded by the new model.
To save cost and speed up development, the current E-Class’ electrical platform was adopted for the G-Class, so while it features the large luxury sedan’s advanced multimedia system, it misses out on the next-generation MBUX touchscreen intuitive interface that debuts with the all-new A-Class, also out from July in Australia.
“MBUX is only workable on the MFA (Modular Front-Drive Architecture) vehicles,” Mr Metzger explained, adding that he would have liked to see the latest technology in the company’s SUV flagship.
Another parts-bin saving was using the X-Class utility’s transfer case, which the Mercedes veteran engineer insists is the only item that the G-Class shares with the pick-up truck, despite similar wheelbase and track dimensions that suggest the two models are related.
With an impressive 55 per cent rise in overall rigidity allowing the latest G-Class to achieve hitherto unachievable on-road noise, vibration and harshness (NVH) targets as well as off-road prowess for the series, it did come at a small packaging cost.
While the rear seat area now offers nine positions, a proposed sliding bench was nixed as it would have compromised the desired level of stiffness in the rear half of the body.
The Mercedes adopts an eight-point mounting system for the body on frame that further cuts NVH, while the B, C and D pillars have a bracing ring for additional torsional reinforcement. There are also other bracing elements in the rear floor to further boost the lower body area integrity, especially off road, but this has meant that the floor is not flat for easier cargo carrying.
“We had to at least match the old G-Class’ famous 4x4 reputation,” Mr Metzger explained.
Among a host of little battles that were won, Mr Metzger highlighted how the reversing camera was relocated to under the spare wheel as part of the cover since the tailgate-mounted spare of old all but blocked the view.
Another involved the new 4.0-litre bi-turbo’s air intake, which is susceptible to water egress during river fording a sensor closes a flap when required and so air is diverted from behind the headlights.
“It was our small team’s passion for the G-Class that came up with answers to problems like these,” Mr Metzger beamed.
That said, he is most proud of delivering a thoroughly modern SUV underneath a retro exterior, even though compromises like wind noise from the upright pillars and exterior mirrors (also cribbed from the next-gen GLE) result due to the much-loved design. It was felt that streamlining the silhouette would have diluted the newcomer’s appeal considerably.
“Considering the level of advanced technology that the G-Class achieves, this is the biggest achievement,” Mr Metzger said. “It was not easy at all to keep the iconic shape in some aspects. We had to ask ourselves, ‘Is it good for the icon that is a Geländewagen?’”
