Abstract: A centrifugal clutch for mechanical transmission which includes a two-part casing and an internal rotor with a pseudo-fluid, material between the casing and rotor, wherein a face of the rotor opposite a face of the casing has a succession of grooves or waves which are substantially sinu-soidally shaped in a peripheral direction, and wherein each internal face of the casing has a succession of concave pockets, which are substantially egg-shaped, as formed by an internal section of an egg-shell cut lengthwise through the egg, with the wider end of the egg cut off to a radius which will conform to the inside diameter of the casing, and with the narrower end of the egg cut off to a radius which will conform to the outside diameter of an internal boss within the casing.The two parts of the casing are joined together to form an annulus and the areas separating the pockets are chamfered adjacent the edges of the pockets and are flat or convex between the chamfered portions.