In 1927 Alfa Romeo entered the medium to low power range segment with the 6C 1500 designed by Vittorio Jano in 1927. The 1.5-litre 6-cylinder engine delivered 44 hp on the road, 54 hp in the S version and 60 hp in the SS version. There were also two variants with a compressor engine, either 76 hp or 84 hp. Low weight, easy handling and good stability were the distinguishing features of the trolley. In 1929 followed the 6C 1750, which had a higher engine power as well as an improved chassis and up to 100 hp.
The body for the racing version was developed by Alfa Romeo from Zagato. The white “Flying Star” with 102 hp, designed by Bianchi Anderloni, is considered the most beautiful model of the series. From the 1750s, Italian automakers produced 2579 vehicles. This was followed in 1933 by the 1900s, of which 197 were built, and in 1934 by the 2300s, the first model to be fitted with a cast-iron crankcase, six cylinder liners and a single-disc clutch. The Turismo, Pescara and Gran Turismo variants were the first single-wheel suspension vehicles in Europe.
The newly developed cylinder heads made of light metal were used for all models from 1933 onwards.
The last pre-war model, the 2500, was built in 1935 and Alfa Romeo offered various body shapes for this series. After the Second World War, from 1946 onwards, the company resumed production with the 2500 series, which had already been redesigned in 1939, and produced 1830 vehicles until 1951. The advanced 6-cylinder engine was based on the 2300, but had a stronger engine and more displacement. In 1950 the Alfa Romeo 1900 finally replaced the 6C.