The Isetta had to be redesigned for BMW’s version of its 250cc single cylinder motorcycle engine. With the changes to the engine done, it made 12 BHP and could reach a top speed of 85 km/h.
It was the world’s first mass produced car to reach a fuel consumption figure of 3L per 100 km and was the top-selling single cylinder car of that time.
In 1956 Germany implemented a law stating that cars were not allowed to use an engine with a displacement of 250cc and below. As a result, BMW increased the engine displacement of the Isetta to 298cc as 300cc was the maximum displacement allowed for the tax category that it was placed in.