Until 1932 BMW manages to sell very well its air-cooled radial engine thanks to its excellent power to weight ratio. They also win the 6000 mile Alpine Rally through four countries.
A new car model from BMW is launched in 1932. It is called the 3/20PS. The powerplant was a 782cc 4 cylinder unit which featured suspended valves and a double chain driving the camshafts, producing 20 horsepower at 3500 rpm and providing the saloon with a 50 mph top speed. It is the first model to be developed entirely by BMW in Munich also known as the BMW AM 4 (Ausfuhrung Munchen 4 Gange - Munich Version 4 Speeds). With this car BMW wins the Concours d'Elegance in Baden-Baden.
The next year, 1933, marked the introduction of the 303 saloon and the first BMW inline-six cylinder power unit, a configuration that will remain even to the contemporary BMW cars. Designed by Fritz Fiedler, the 303 engine had a chain driven camshaft, with pushrods and rocker arms to vertical overhead valves. The crankshaft of the new BMW 303 6-cylinder engine was designed by Rudolph Schleicher. The 303 was also the first BMW to use the twin-kidney shaped radiator grilles, another current trademark. Using a welded tubular steel frame, independent front suspension and rack and pinion steering, the 303 was a benchmark in technological achievements. Its 1173cc engine provided 30 horsepower and a top speed of 56 mph (90 km/h).
Based on Pratt&Whitney design, BMW makes the air-cooled radial engine in 1934. Three of these engines power the famous JU52 airplane, who served both civilian and military service during the 1930s and 1940s.
It's the year when the 315/1 roadster appears on the market. It had a beautiful sleek design for it's time with low cut doors. The engine was a 1.5 liter, in-line 6 cylinder developing 40bhp. The top speed was around 125km/h making the 315/1 one of the most competitive sports car of the era winning the international Alpine Trials. It was also a clear winner in the 2000km race across Germany.
1935 marks another innovation from BMW in the motorcycle industry. The K12 is the first motorcycle with a hydraulically damped telescopic front wheel fork. It replaced the old leaf spring fork. The 315 roadster becomes the undisputed champion in the 1.5 liter sports car category.
The successor of the 315 was the 326. The development of this car began in late 1934 by Fritz Fiedler and chief designer Alfred Böning. The design was Peter Schimanowski's work. The engine had an output of 50bhp. It featured also some advanced technical innovations for that time like hydraulic braking system and rack and pinion steering. The 326 was available as a saloon, a two-door or four-door convertible.
BMW comes up with the amazing 328 roadster in 1936. This car is a legend in the racing history, one of the best and one of the most beautiful cars that BMW has ever created. As recognition, the 328 roadster was nominated for the Car of the Century. The car makes its competition debut at the famed Nürburgring racetrack in June 1936, and proved unbeatable in international sportscar races in the two-liter class. The beautiful lines, like the integrated headlamps set a trend which was to survive well into the fifties. In 1940 it wins the famous Mille Miglia race. The engine was a 2 liter, in-line 6 cylinder with 80bhp.
Although the numbers are not in a regular succession, the 327 appeared on the market in 1937, one year after the 328. The styling had the same signature, Peter Schimanowski, which meant that it looked stunning with two-tone paintwork. It came with a coupé or cabriolet body. The 327 had a short version of the 326's chassis. The top engine developed 80bhp. A total of 1396 cars were made.
A new world speed record is set by BMW in 1937. Ernst Henne becomes the fastest man on two wheels riding a 500 ccm compressor machine developing 108bhp. This bike had an aerodynamic body to better pierce through the air at high speeds. On the Frankfurt-Darmstadt motorway, Henne attends 173.686mph (279.508 km/h), a record that will stand for the next 14 years.
1938 sees more motorsport wins for the 328 roadster.
George Meier is the first foreigner to win the Isle of Man Senior TT in 1939 - the world's toughest motorcycle competition of its day. Shortly before the outbreak of the Second World War, BMW takes over the Brandenburgische Motorenwerke in Berlin-Spandau and factories in Basdorf and Zühlsdorf near Berlin.