Method for assembling a roller bearing comprising an outer ring and an inner ring each provided with an annular raceway (1a, 2a) between which are arranged taper roller bearings in such a way as to allow for the relative rotation of said rings about an axis, with each one of said raceways having an axial support (4, 5) whereon the taper roller bearings are bearing against by the intermediary of the tapered periphery thereof, said axial supports extending each one between an outside edge and an inside edge by having a tapered geometry, with the outer ring provided with a collar having a radial bearing support whereon the taper roller bearings are bearing against by the intermediary of a lateral face, said bearing comprising a retaining cage that has an outer crown, an inner crown and a plurality of bridges extending between said crowns in such a way as to form between two adjacent bridges and a segment (11a, 12a) of each one of said crowns a peripheral frame whereon a bearing is retained by being able to rotate about its own axis Y, with the segments able to be deformed from a configuration with an arrangement of the bearings on the peripheral frames to a configuration of retaining said bearings on said peripheral frames, with said method providing, after the arrangement of the bearings inside the raceway of the outer ring, to arrange each bearing on a peripheral frame by deforming the retaining cage, with the inner ring then being mounted in the outer ring by arranging the bearings on the inside raceway, with the arrangement of each bearing on a peripheral frame comprising a relative axial translation of the retaining cage with respect to the outer ring, with at least the segments of the inner crown being reversibly deformed by bearing on the bearings during the translation in order to have a stressed state having an outer diameter that is sufficiently reduced to allow for the arrangement of each bearing on a peripheral frame, each segment of the inner crown having an internal face which is arranged axially facing the lateral face of a bearing, said method characterised in that the deformation is carried out during the relative axial translation of the retaining cage in relation to the outer ring so that, after deformation and via elastic return of said segments after the bearing course thereof: - at least the central zone of the segments of the inner crown is inscribed in a maximum diameter D max which is separated from the diameter D of the inside edge of the inside axial support by a dimension C which is such that C ≤ 20% D, with the internal face having an outside edge having, at least on the central zone thereof, the maximum diameter D max; - an inside edge of the internal face has, at least on the central zone thereof, a minimum diameter D min which is greater than or equal to said diameter D. - at least the central zone of the segments of the inner crown is inscribed in a maximum diameter D max which is separated from the diameter D of the inside edge of the inside axial support by a dimension C which is such that C ≤ 20% D, with the internal face having an outside edge having, at least on the central zone thereof, the maximum diameter D max; - an inside edge of the internal face has, at least on the central zone thereof, a minimum diameter D min which is greater than or equal to said diameter D.