A skid steer machine having separate left and right hydraulic propulsion units includes an operating ratio change system by which the ratio of the propulsion speed of at least one of the hydraulic propulsion units versus the hydraulic flow directed to the propulsion units can be changed from at least a first ratio to a second ratio and inversely. The operating ratio change system includes an operating ratio change ECU which controls an operating ratio change device to operate in at least a first ratio configuration or a second ratio configuration, and the operating ratio change system operates in an automatic operating mode where the operating ratio change ECU selects the operating ratio according to machine parameters received by the operating ratio change ECU.