Asymmetrical involute spur gears have different pressure angles on the drive side and coast side. A rational design of the tooth profile of such gears can lead to an increase in gear load capacity, a reduction in noise and vibration levels and a significant enhancement in bending strength. The authors have developed tooth profile equations for the above mentioned spur gears and relevant computer programs with calculation examples being given. In addition, a three dimensional solid model of the spur gears...