In the midst of an economic crisis, the year 1932 was not an auspicious time for motor sport activities in Germany. Even the racing department at Mercedes-Benz, whose supercharged model K, S, SS, SSK, and SSKL touring cars had dominated the European motor sport scene in the late 1920s and the start of the 1930s, was closed.
Yet there was hope for the future. In autumn 1932, the motor sport authority AIACR (Association Internationale des Automobile Clubs Reconnus) announced a new formula for Grand Prix racing that would apply from 1934. Cars were permitted to weigh a maximum of 750 kilograms without fuel, oil, coolant, and tyres, but there were no other design restrictions. In 1933, Mercedes-Benz decided to develop a completely new racing car for the new formula. The racing team for 1934 was to include Manfred von Brauchitsch, Rudolf Caracciola, Luigi Fagioli, Hanns Geier, and Ernst Henne.
The intention of the AIACR’s 750-kilogram formula was to limit the speed of racing cars compared to the previous generation: the rule makers assuming that only small engines with a low power output could be installed in lightweight racing cars. However, they underestimated the technical advances that had meanwhile been made. The W 25 developed in Stuttgart for the new formula was an extremely powerful racing car and, during the period of the 750-kilogram formula up to 1937 alone, the engine output of Mercedes-Benz racing cars would almost double up to a maximum of 475 kW (646 hp) thanks to continuous development.
A Powerful Winner
The designers at Mercedes-Benz opted for a classic vehicle architecture – a front mounted engine driving the rear wheels via a transmission on the rear axle – which appeared relatively conservative compared to its mid-engine rival from Auto Union. The in-line eight-cylinder engine originally had a displacement of 3.4 litres and featured supercharging technology that had already fully proven its worth in racing. The displacement was later increased to a maximum of 4,740 cubic centimetres and, depending on the version, engine output was between 260 kW (354 hp) and 363 kW (494 hp): allowing a top speed of up to 300 km/h. The combination of such a powerful engine with a slim body and independent suspension proved an instant winner.
For the W 25, Mercedes-Benz opted for a silver finish for the first time. How the racing car acquired this livery, which would later give rise to the name of the ‘Silver Arrows’, is one of the great stories from 120 years of motor sport at Mercedes-Benz. Legend suggests that the night before its first deployment in the International Eifel Race, while painted in the traditional German racing livery colour of white, the W 25 weighed in at the Nürburgring just a single kilogram over the limit.
During the evening before the race, racing manager Alfred Neubauer had a brainwave: that the traditional white paintwork should to be removed to produce the necessary weight saving. In his memoirs, published in 1958, Neubauer described the overnight scene in the pits: “Throughout that long night, the mechanics scrubbed the beautiful white paintwork from our Silver Arrows. When they were put on the scales again next morning they weighed precisely 750 kilos.”
With Manfred von Brauchitsch at the wheel the W 25 won the race, founding the unique success story of the Silver Arrows. The car raced between 1934 and 1936 and was continuously developed and enhanced during this time. In 1935, it carried Rudolf Caracciola to the European Championship title, with two further Grand Prix victories in 1936: Tunis (Algeria) and Monaco.