Abstract: An improved envelope seal for a tire assembly (10) is provided to protect the bonding surfaces of a tire casing (12) and tread material (14) from exposure to steam and other elements within a pressure chamber (126) during curing. A two piece road curing rim (26) is provided with rim members (36, 38) which extend adjacent the sidewalls (56) of the tire (16). Annular seals (37, 39) are secured about the peripheral edges of the rim members (36, 38) and define first annular sealing faces (86, 88) and second annular sealing faces (90, 92). A flexible envelope (18) covers the bonding surfaces of the tire and extends radially inward adjacent the sidewalls of the tire. The envelope has lips (68, 70) extending laterally outward from the outer surface thereof and having annular sealing faces (94, 96) defined thereon. The envelope (18) is inflated to align the first annular sealing faces (86, 88) and annular sealing faces of the envelope lips (94, 96).