A base (1) is provided for a ski boot (2) and comprises a sole (4) and an outsole element (8, 9) that is positioned in a predetermined position relative to a longitudinal axis (L). The outsole element (8, 9) is positioned on the sole (4) by using two projections (25, 26) that are carried by one or other of the sole (4) and the outsole element (8, 9) and that locate in holes or cavities (22, 23) defined by the other. Preferably, the projections (25, 26) are carried by the outsole element (8, 9) and locate in holes or cavities (22, 23) defined by the sole (4). The projections (25, 26) may be integrally formed with the outsole element (8, 9) or the sole (4). Alternatively, they may be formed by injected pins, rivets, fasteners, t-nuts, or screws.