The present invention relates to a radial tire and a radial tire-rim assembly. The radial tire (1) has a pair of beads (2), each bead having a bead core (3) and a bead apex (5), a carcass (4), with both edges thereof folded back around said bead core and fastened to said bead core, a tread (6), a belt layer (7), and an aspect ratio smaller than 60%. The tread is wider (in the axial direction) than the maximum width of said carcass and the edges of said tread are positioned within a range of 50-100% of the height of the cross-section of the carcass. This structure provides the tire side with rigidity and permits the tread to deform so that is supports the weight of the car and runs safely even when the tire pressure is decreased. The radial tire-rim assembly is characterized in that the bead of the radial tire has a toe (9) extending inward (in the radial direction of the tire) and is further provided with a hump groove (10) corresponding paramently,, the rim (20 ) has an annular groove (22) and hump (23) which fit into the toe and groove, respectively. These arrangements prevent the bead from separating from the rim when the tire pressure is decreased or at a time of sharp cornering.