This change in regulations encouraged BMW to revise their Isetta microcars. In February 1956 a 300cc engine was introduced. The engineers enlarged the single cylinder to a bore and stroke, which gave a displacement of exactly 298 cc; at the same time, they raised the compression ratio from 6.8 to 7.0:1. As a result, the engine power output rose to at 5200 rpm, and the torque rose to at 4600 rpm. The maximum speed remained at , yet there was a marked increase in flexibility, chiefly noticeable on gradients.