A gyratory crusher outer crushing shell (106). The outer shell comprises three regions along its axial length including: an inlet region (121) that tapers radially inward from an uppermost first end (124); a crushing region (123) that extends radially inward from a second lowermost end (125) and; a radially innermost shoulder region (122) that is positioned axially between the inlet and crushing regions. An angle of inclination (a,b) of a radially inward facing surface at the inlet and shoulder regions and the axial length (C) of the crushing surface are designed to optimise crushing capacity in addition to maximising reduction.
