Abstract: A heavy duty radial tire improved in bead durability and airtightness, which comprises a pair of axially spaced bead portions having a bead base to fit with a 15.degree. tapered bead seat of its regular rim, and a bead core disposed in each of the bead portions, the bead core having a polygonal cross sectional shape having an axially inner vertex point (Q1) and an axially outer vertex point (Q2) and a side (L1) extending between the points (Q1 and Q2), the side (L1) being adjacent to and substantially parallel with the bead base, the maximum section width (CW) of the bead core in the direction parallel with the side (L1) being in the range of 0.063 to 0.105 times the rim width (RW) between the bead heel points (P), the axial distance (A) of the axially inner point (Q1) from the bead heel point (P) being 0.073 to 0.125 times the rim width (RW).

Abstract: A heavy duty radial tire and rim assembly comprising a pair of bead cores, a carcass, a belt, and a pair of bead apexes, wherein in at least one of the bead portions, when the tire is mounted on a normal rim specified for the tire and inflated to a normal pressure, a thickness center line of a carcass turnup portion between two points is cured and located axially inward of a straight line drawn between the two points, the quotient (X/HR) of the axial distance (X) of the inner end (Q2) of the bead core from a bead heel point (Q1), to the height (HR) of a flange of the normal rim is in a range of 0.8 to 1.05, wherein the bead heel point (Q1) is defined as in intersection of an extension of the outer surface of the bead portion with an extension of the bead base, and the quotient (Y/HR) of the radial distance (Y) from the radially outer end (Q3) of the flange of the rim to the radially outer end (Q4) of the bead core, to the height (HR) of the flange of the rim is in a range of 0 to 0.3.

Abstract: A pneumatic tire is provided with at least one radially disposed ply of steel cord fabric turned-up around each bead core to terminate axially outwardly thereof and has a chafer strip disposed adjacent to and axially outwardly of each turn-up. The chafer strip comprises a folded strip of steel cord fabric which fabric is less rigid than the fabric of the carcass ply. The folded portion of the chafer strip is disposed radially outwardly of the ends thereof and is positioned to cover the edge of the turned-up end of the carcass ply.