Hypoid bevel gears are a type of spiral bevel gears where the axes of the two gears do not intersect. The shape of a hypoid gear is a hyperboloid of revolution, i.e. the pitch surface of a hypoid gear is a hyperbolic surface, as opposed to a spiral bevel gear which is normally conical. The hypoid gear configuration places the pinion gear off-axis relative to the ring gear, which allows the pinion gear to be larger in diameter with more contact area. In hypoid gear design, the pinion and ring gears are always of opposite hands, and the spiral angle of the pinion gear is usually larger than that of the ring gear.