Radial tyre

A radial tyre having sidewalls (3) which are bulged-out under a normally inflated state of the tyre so as to satisfy the following conditions: the total (HA+HC) of a height (HA) and a height (HC) is not less than 0.818 times the total (HA+HB+HC) of the height (HA), the height (HB) and a height (HC); and a distance (HE) is not more than 0.575 times a distance (HD), wherein (HA) is the radial distance between points (C and P1), (HB) is the radial distance between the point (P1) and a point (P2), (HC) is the radial distance between the point (P2) and a point (P3), (HD) is the radial distance between the point (P3) and a point (P4), and (HE) is the axial distance between the points (P3 and P4), the points (C and P1) are on the outer surface of the tyre tread portion (2), the points (P2, P3 and P4) are on the inner surface of the tyre at the tread portion (2), the bead portion (4) and the sidewalls (3), respectively, the points (P1, P2 and P3) are at the same axial distance from the tyre equator (CO) as the bead heel point (PO), the point (P4) is the axially outermost point of the tyre inner surface.