The Isetta chassis was lengthened to create the BMW 600, since BMW knew that it needed a larger four-seat family car to keep up with the rising wealth and expectations of the German people, but could not afford to develop a new model from scratch. The rear-mounted engine was increased in size from and the 600's rear suspension was BMW's first use of the semi-trailing arm system that would be used on their sedans and coupes until the 1990s. Released in 1957, the 600 could not compete against the larger, more powerful Volkswagen Beetle. Production ended in 1959 after fewer than 35,000 were built.