You will notice that these gears have a Hypoid shape cut into them. They are not like the M-22 gears which are often misnamed as straight cut gears. In all truthfullness they have less curve cut into them. Basically when you add a curve to a gear it has more area and makes less noise. M-22 Gear sets are notorious for damage deep in the root of the tooth from Cavitation and Vibration
