An agricultural combine for supporting an agricultural header and carrying that agricultural header to a field to harvest a crop. The combine includes a chassis, front and rear drive wheels, a hydraulic motor, a device for sensing and a controller. The front and rear drive wheels support the chassis. The hydraulic motor is drivingly coupled to the front wheels. The device for sensing senses a presence of a header mounted to the combine. The controller is configured to monitor the device for sensing and to change the specific displacement of the hydraulic motor dependent upon the presence of the agricultural header.