The Mercedes-Benz W31 typ G4 was a German three-axle off-road vehicle first produced by Mercedes-Benz as a staff/command car for the Wehrmacht in 1934. The cars were designed as a seven-seater touring car or closed saloon and were mainly used by upper echelons of the Nazi regime in parades and inspections as they were deemed too expensive for general Army use.
The G4 was a development of the G1, launched in 1926. In the first three years of production they had an 8-cylinder inline engine of 5018 cc displacement delivering 100 PS (74 kW). An unsynchronized four-speed transmission transferred the power to all four rear wheels, or optionally to all six wheels. The rear wheels were attached to two rigid axles 950 mm apart, which were suspended in joint semi-elliptic leaf springs. The front axle was rigid with semi-elliptic springs. All six wheels had hydraulic brakes with servo assistance. The top speed was only 67 km/h (42 mph), limited by the type of all-terrain tyres. Only 11 of these vehicles were delivered to the Wehrmacht. The car used an elongated box-section frame that allowed for generous interior room with comfortable seating for up to 7. Seating was provided by two benches (front and rear) and one middle-placed row of seats with separate arm rests.
From 1937 a more powerful engine of 5252 cc and 115 PS (85 kW) was used. The performance remained the same. Between 1937 and 1938 16 cars were built.
From 1938 a larger motor of 5401 cc and 110 PS (81 kW) was used. Vehicles of this model were used by Adolf Hitler and his staff in parades marking the occupation of Austria and the annexation of the so-called residual Czech Republic. The last year of production was 1939. 30 cars of this model were built.
Of the 57 cars produced at least 3 exist in original form. A car used during the annexation of Czechoslovakia and Austria in the early stages of the war is preserved at the Sinsheim Auto & Technik Museum. After World War II, this vehicle was first converted to a fire engine, before finally being restored and donated to the museum. Another G4, originally a gift from Hitler to General Franco, is in the car collection of the Spanish royal family. Another is in Hollywood. In the TV series "Hogan's Heroes" it appears in the credits and some scenes of the series. This vehicle has also appeared in other Hollywood films, mainly in war movies.
In 2009 in the U.S., a classic car collector offered three W31s for sale for $9 million. With unproven claims of use by Adolf Hitler, they included a blue convertible and a grey Wehrmacht W 31 with a closed cab. A special feature of the convertible was that the front passenger seat could be folded up, so it was possible to stand upright in the car.