Already in 1926, engineers in the newly-create Daimler-Benz AG built a further vehicle into which flowed the know-how in construction of off-road capable vehicles. The G 1 (W 103 series) was produced in response to a competition announced by the Reichswehrministerium (Ministry of the German Realm Defence), which required a manoeuvrable vehicle for battlefield operations. Other companies taking part were Horch and Selve. While the G 1 was an off-road vehicle, it did not have all-wheel drive: there were three axles of which the two, twin-tyre rear axles were driven (6x4 drive principle). The competition was won by the Horch 8 – designed by Paul Daimler, who was that company’ s Technical Director from 1923 to 1928.

Daimler-Benz continued its development work, producing the G 3 (1928) and G 3a (1929) trucks as derivatives of the G 1, though with a considerably longer wheelbase than the G 1 (647 and 847 millimetres respectively between the front and first rear axle, depending on the version). The ground clearance was increased to 265 millimetres. Both G 3 vehicles likewise featured two driven rear axles (6x4), which were also equipped with differential locks. This gave them a very good off-road performance (climbing ability 25 per cent); however they were not all-wheel-drive vehicles.

1934 saw the introduction of the mighty, six-wheeled G 4 passenger vehicle (W 31 series), which was built at the Untertürkheim plant. It was initially conceived for hard military use, but with a kerb weight of around 3.7 tonnes it proved too heavy for this purpose. However, heads of state and high-ranking officers soon came to appreciate it as a highly prestigious off-roader. Power was transferred to the two rigid rear axles by a prop shaft, while two locking differentials ensured good off-road capabilities (climbing ability when fully laden: 43 per cent). A vacuum brake servo system was available as an option – no doubt a welcome addition in view of the vehicle’s weight. A total of 57 units in all engine variants were built prior to 1939.

The first series (1934 to 1936) was powered by a model M 24, 5.0-litre eight-cylinder engine developing 100 hp (74 kW) at 3400 rpm. For the second series (1937 to 1938) the engine was enlarged to around 5.3 litres, with an output of 115 hp (85 kW), increasing to 110 hp (81 kW) and 5.4 litres in the third series. Although more would have been feasible, the G 4 was only certified for a maximum speed of 67 km/h owing to its great weight and the technical limitations of tyres at the time. The G 4 had an immense thirst, with a fuel consumption of 28 litres per 100 km on the road and 38 litres off-road. No wonder some vehicles were fitted with a 140-litre tank.

Only very few G 4s survived the turmoil of the Second World War – only three absolutely authentic examples are known to exist. One of these, built in 1939 and owned by the Spanish royal family, was sent to the Mercedes-Benz Classic Centre in Fellbach for partial restoration in 2001. The brief for this work was to overhaul all the technical features and restore them to full working order if necessary, but to leave the patina of this rare vehicle untouched. Its condition has been preserved.

In the 1930s, Mercedes-Benz designed a number of all-wheel-drive vehicles, mainly for use by the German armed forces, although the customer ultimately decided otherwise. These included model 160 HM (W 133 II series) in 1935/36 and model 160 VL (1936, W 139). In 1935 the company also produced the 170 VG Kübelwagen (W 133 III series) with a selectable front-axle drive. In 1936 this was followed by the 170 VL (W 139) with permanent all-wheel drive as a precursor to the G 5 still equipped with a 1.7-litre engine. For greater manoeuvrability this also featured selectable four-wheel steering, which reduced the turning circle from eleven metres to seven metres. Roughly 100 vehicles of the two models together were delivered in total.