The inception of the company resulted from the merger of two companies, Grondona Comi & C and Miani Silvestri & C in 1899. Originally, OM manufactured railway stock. Car production started in 1918, using the plant of the former Brixia-Zust, just after OM took over Zust car company of Brescia, Northern Italy. The first OM car, Tipo S305, primarily an old Zust model, appeared in 1918 with a 4712 cc four-cylinder side-valve in-line engine.
Further models were Tipo 465 in 1919, Tipo 467 and Tipo 469 in 1921. 1923 saw an all new model, Tipo 665 'Superba' with a 2-litre six-cylinder engine. This model was extremely successful in racing, winning top five positions in the 2-litre class in 1925 and 1926 at the Le Mans but its greatest achievement was the victory in the first Mille Miglia race in 1927 where Ferdinando Minoia and Giuseppe Morandi led home an O.M. '123' at an average speed of for 21 hours 4 minutes 48 seconds. Some cars were equipped with Roots superchargers. In 1925 OM began to build trucks and buses, using licensed Swiss Saurer engines and other mechanical components. Ties with Saurer persisted through all of OM's history.
OM was taken over by the Fiat Group in 1938 and in the following year passenger car production ceased, and OM became a commercial vehicle and train part manufacturer. Main new product in the WWII post-war era was the Leoncino a light truck in the 2.0 to 2.5 tons range, which was an immediate success. It became the forefather of several series of heavier but structurally similar models, namely Tigrotto, Tigre, Lupetto, Cerbiatto and Daino, launched between 1957 and 1964. Bus chassis versions of several of these models were also available. In the 60s and 70s the light and medium-weight OM truck ranges were sold in Switzerland as Saurer-OM or Berna-OM, in Austria as Steyr-OM, in France as Unic-OM, and in Germany as Büssing-OM.
The end of OM
In 1968 OM was definitively merged into the Fiat Group as a brand belonging to the Commercial Vehicles division, which also included Fiat and Unic. In 1975 it was absorbed into IVECO and the OM brand disappeared from the truck and bus markets, although it still survives as an independent forklift manufacturer.
