A rotorcraft rotor with hinged blades, includes: a hub; a plurality of blades hinged to flap relative to the hub; bottom abutments of the hub, and bottom abutments of the blades suitable for co-operating with the bottom abutments of the hub; and top abutments of the hub, and top abutments of the blades suitable for co-operating with the top abutments of the hub; the top abutments of the hub being movable between a deployed position in which they extend facing the top abutments of the blades, and a retracted position in which they are offset angularly away from the top abutments of the blades. The rotor also includes elements for locking the top abutments of the hub in the deployed position, and inertial means for releasing the top abutments of the hub and for deactivating the locking means.