This paper presents a study on the surface load bearing capacities of WN (SymMarC and Haseg SymMarC) and involute gears. A method for calculating contact stress of WN gear teeth in mesh, which was developed by the authors, was indicated. The contact stresses of WN and involute gear teeth with various dimensions were calculated under different applied loads. The relations between the applied load and maximum contact stress and the surface load bearing capacities of WN and involute gears were determined. The maximum contact stresses of WN gears were found to be relatively larger than those of involute gears for smaller applied load, but to become relatively smaller than the latter for larger applied load. WN gears are considered to be better to use than involute gears for the case of larger module and applied load and smaller helix angle and number of teeth
