A device for mounting a tread ring onto a tire carcass, the device comprising: a tread ring expansion assembly having: a tread ring-receiving cavity configured to receive a tread ring and a tire carcass receiving cavity configured to receive a tire carcass, the tire carcass-receiving cavity arranged radially inward the tread ring-receiving cavity; a plurality of tread expanding members having tread receiving surfaces, the tread expanding members being arranged in an annular arrangement radially outward the tread ring-receiving cavity and configured to translate outward in a radial direction relative to the tread ring-receiving cavity while the tread ring is under vacuum pressure from a tread engaging arrangement to a tread expanding arrangement, the tread receiving surfaces being configured to contact the tread in the tread engaging arrangement prior to translation to the tread expanding arrangement and the tread receiving surfaces being further arranged in fluid communication with a vacuum pressure source in both the tread engaging and the tread expanding arrangements; a first side wall and a second side wall arranged annularly on opposing sides of the plurality of tread expanding members and the tread ring-receiving cavity, the side walls (34, 36) extending radially relative to the tread ring-receiving cavity and being configured to engage the side edges of a tread ring when arranged within the tread ring-receiving cavity and to maintain engagement with the side edges of the tread ring during tread ring expansion; and means for translating the plurality of tread expanding members between the tread engaging and tread expanding arrangements. a tread ring-receiving cavity configured to receive a tread ring and a tire carcass receiving cavity configured to receive a tire carcass, the tire carcass-receiving cavity arranged radially inward the tread ring-receiving cavity; a plurality of tread expanding members having tread receiving surfaces, the tread expanding members being arranged in an annular arrangement radially outward the tread ring-receiving cavity and configured to translate outward in a radial direction relative to the tread ring-receiving cavity while the tread ring is under vacuum pressure from a tread engaging arrangement to a tread expanding arrangement, the tread receiving surfaces being configured to contact the tread in the tread engaging arrangement prior to translation to the tread expanding arrangement and the tread receiving surfaces being further arranged in fluid communication with a vacuum pressure source in both the tread engaging and the tread expanding arrangements; a first side wall and a second side wall arranged annularly on opposing sides of the plurality of tread expanding members and the tread ring-receiving cavity, the side walls (34, 36) extending radially relative to the tread ring-receiving cavity and being configured to engage the side edges of a tread ring when arranged within the tread ring-receiving cavity and to maintain engagement with the side edges of the tread ring during tread ring expansion; and means for translating the plurality of tread expanding members between the tread engaging and tread expanding arrangements.