1958 BMW Isetta 300

Its name meaning 'little Iso,' the Isetta was designed and first manufactured by the same Italian firm that later produced the exotic Iso Rivolta, Iso Fidia and Iso Grifo. The Isetta was also built under license by both Velam in France and BMW in Germany and is credited as being the car that saved BMW. While exported to America, their small size, poor performance and unusual appearance made them an unpopular alternative to other economy cars and few were sold. Other cars that competed against the BMW in the 'micro-car' market segment included the German Messerschmitt, Italian Fiat Bianchina, and the French Mochet Velocar.

It was produced during/after World War II as an alternative to the Volkswagen bug. This vehicle was produced from April of 1955 through 1962.

The BMW Isetta 25 was powered by a one-cylinder, four-stroke, 247cc motorcycle (BMW R25/3) engine that generated 12 horsepower (9 kW). It used a Bing sliding throttle side draft motorcycle carburetor, and cast iron was used to form the cylinder and crankcase, and aluminum for the cylinder head. Unlike the motorcycle engine, the head was rotated by 180-degrees. The Isetta and BMW unit used different twin-bearing crankshaft, with the BMW unit being larger and with reinforced bearings. The BMW Isetta used a four-speed gearbox.

Many of the major elements remained true to the initial design of the Italian firm Iso SpA, however, BMW re-engineered much of the car. The 'bubble window' styling remained true to its Italian heritage but distinguished via the BMW badges and the headlamps which were now fixed to the sides of the bodywork.

Due to its small stature, the Isetta 250 could be driven in Germany with a motorcycle license. This changed in 1956 when the government of the Federal Republic of Germany changed the regulations for motor vehicles. From that point forward, Class IV licenses could only be used to operate small motorcycles and no longer applied to motor vehicles with engine capacities less than 250cc. At the same time, the maximum capacity allowed for the Isetta's tax category was 300 cc. Individuals who had received Class IV licenses before the change in regulations were grandfathered and permissible.

BMW responded to this change by introducing a 300cc engine in February of 1956. The single cylinder's engine displacement was given a 72mm bore and 783mm stroke, resulting in a 298cc size. The compression ratio was increased from 6.8 to 7.0:1 and power rose to 13 horsepower at 5,200 RPM. The torque also increased to 13.6 ft-lb at 4,600 RPM. The top speed, however, remained the same at 53 mph (85 km/h).

Between 1956 and 1962, a total of 161,360 examples of the BMW Isetta 300 were built.

A more conventional four-wheel version arrived in mid-1957 and remained in production through November of 1959, with a total of 34,813 examples built. Known as the BMW 600, this was BMW's first postwar four-seater economy car. The front-engine styling remained nearly unchanged from its three-wheeled Isetta siblings, but its wheelbase had been stretched and a conventional rear axle had been added to accommodate four seats. Mounted at the rear was a 582cc flat-twin engine from the R67 motorcycle. It offered 19.5 horsepower at 4,500 RPM and was backed by a four-speed manual gearbox. A Saxomat semi-automatic transmission was available as optional equipment.

The BMW 600 had a wheelbase size of 66.9-inches, a length of 114.2-inches, and a width of 55-inches. The front track was 67 inches while the rear track was much shorter at 46 inches. It used a new perimeter frame with box-section side members and straight tube cross-members. The rear suspension used an independent semi-trailing arm setup.