In the expanding U.S. commercial mowing market the zero turning radius mowers (ZTR) are gaining popularity. They offer exceptional maneuverability and productivity over conventional riding mowers.The ZTR function is generally accomplished by rotating one wheel forward and the other wheel backward with two hydraulic pumps and two hydraulic motors. The rear axle is equipped with caster wheels. Common to most ZTR mower designs; the travel speed and direction are controlled by two vertical levers located in front of operator's seat. This occupies the operator's hands all the times. Moreover, these two wheel drive designs have limited slope climbing capabilities.KUBOTA introduced a four wheel drive front mower in 1986, which greatly improved operation on slopes.This paper details the design concept and the unique mechanical drive system of a new 4WD front mower which provides the ZTR feature utilizing a conventional steering wheel.