After the end of the war, NSU, like most other factories, lived off the remaining stocks. But already in 1920/21 the first newly manufactured vehicles came out. Mainly bicycles and motorbikes were built, especially the proven army machine. Demand also began to grow in the accessories sector, and freewheel hubs were soon produced, one every 30 seconds.

At the celebration of the company’s 50th anniversary, which took place only on 12 April 1924, one could even look back on an astonishing factory expansion, especially for the inflation years. The factory now had its own telephone exchange, laboratories and even its own photo studio. In the same year, work also began on the construction of a branch factory in Heilbronn, which, however, was not completed until 1927/28. In the course of the concentration tendencies in German motor vehicle manufacturing, NSU merged with Schebera AG, a Berlin-based coachbuilding company belonging to the Schapiro Group.

The new name from November 1926 was NSU Vereinigte Fahrzeugwerke AG, Neckarsulm. While production continued at the company‘s headquarters, the former Schebera became involved in sales and took over the taxi business in Berlin in particular. NSU cars were frequently seen on the streets of the Reich capital as rental cars. However, when, as a result of the overcrowding in the trade, the earnings of the individual cab owners here became increasingly slim and they were no longer able to pay their instalments to the factory, NSU hit the skids in 1926. Necessary renovations dragged on until 1928 and resulted in the Italian automobile giant Fiat buying the Heilbronn plant for passenger car production. From then on, Fiat bought chassis from NSU, on which they built their own bodies. This was the end of car manufacturing in Neckarsulm. Until 1932, Fiat built only NSU cars in Heilbronn and marketed them under the name NSU Fiat. This brand name was retained even when only Italians such as the Fiat types 500, 1000 and 1100 came off the production line in Heilbronn.

In 1927/1928, the NSU branch factory in Heilbronn was ready for occupation. Shortly after completion, however, it was taken over by Fiat. The Italian automobile company manufactured automobiles in Heilbronn, such as the Type 7/34 PS shown here, which were marketed under the name NSU.On 1 January 1930, Fritz von Falkenhayn was appointed sales manager at NSU, two years later a member of the board of directors and six years later chairman of the company‘s board of directors. He began to build up a powerful sales organisation. A customer service centre was set up, and a showroom always offered the complete programme for viewing. However, a sales alliance with the Wanderer Werke in Chemnitz, founded in 1929, hardly came to fruition, as the Saxons gave up all motorbike manufacturing shortly afterwards.

A new attempt in this direction – coordination and unification of production and sales with Deutsche Industriewerke AG in Berlin (D-Rad) – led (1932) temporarily to the company name NSU

D-Rad-Vereinigte Fahrzeugwerke AG Neckarsulm. In 1936, NSU took over Opel‘s entire bicycle production. Shortly afterwards, however, there were no more D-wheels, and so this addition disappeared from the name again in 1938.