1939: Double victory of 1.5-litre racing cars in Tripoli
After winning six races, the W 154 was systematically developed for the 1939 season. In its further improved chassis, the V12 now developed 480 hp. It proved to be another exiting season with numerous Mercedes-Benz victories, culminating in three titles: Hermann Lang won the European and German Hill-Climb Championships while Rudolf Caracciola became 1939 German Road Race Champion.
Participation in the Tripoli Grand Prix, won by Mercedes-Benz in 1935, 1937 and 1938, was, to everyone's surprise, limited to 1.5-litre racing cars in 1939. It was rumoured that organisers wanted to give the Italian manufacturers a better chance of victory; the marked dominance of Auto Union and Daimler-Benz in the three-litre formula races is likely to have played a role here.
However, in the unbelievably short time of only eight months, the Stuttgart team developed the 1.5 litre W 165 car for this race. Its supercharged V8 engine developed a remarkable 254 hp. After just a single test a few days before the competition, race organiser Alfred Neubauer's team sent out Rudolf Caracciola and Hermann Lang to race against a superior line-up of 28 Italian and British racing cars. Daimler-Benz demonstrated its excellence with a famous double victory when Lang won the race ahead of Caracciola. The third-ranking Alfa Romeo was one lap behind when it crossed the finishing line. The W 165 was not entered in any other races in 1939. The view was held that frequent participation would devalue the regular three-litre formula for Grand Prix cars.
All racing activities were discontinued at the end of 1939 after World War II began.