NSU Motorenwerke possible that in 1955, NSU became the biggest motorcycle producer in the world. NSU also holds four world records for speed: 1951, 1953, 1954, and 1955. In August 1956, Wilhelm Herz at the Bonneville Salt Flats, Utah, became the first man to ride a motorcycle faster than . In 1957, NSU re-entered the car market with the new Prinz (Prince), a small car with a doubled NSU Max engine, an air-cooled two-cylinder engine of and . Motorbike production continued until 1968. NSU's last production motorcycle was the Quick 50. In 1964, NSU offered the world's first Wankel engined car: the
Land speed record a speed of 91 mph (146.25 km/h) and receiving the sobriquet the "Fastest Girl on Earth". She drove a six-cylinder Napier motorcar, a 100 hp (74.6 kW) development of the K5, in a speed trial in Blackpool. A subsequent record was held by Lee Breedlove, the wife of Craig Breedlove, who piloted her husband's "Spirit of America - Sonic 1" to a record of in 1965, making her the fastest woman alive, . According to author Rachel Kushner, Craig Breedlove had talked Lee into taking the car out for a record attempt in order to monopolize the salt flats for