Abstract: A pneumatic tire including a carcass containing a ply of cords defining the innermost reinforcing cord layer extending between bead portions, and an airtight layer disposed inside the cords of the carcass ply along the inner surface of the tire, covering substantially the entire inner surface of the tire, wherein the airtight layer is made of air-impermeable rubber including at least 10 weight % of halogenated butyl rubber and/or halogenated isobutylene-paramethyl styrene copolymer in its rubber base, and the thickness of the airtight layer measured from the inner surface of the tire to the cords of the carcass ply is in a range of from 0.2 to 0.7 mm.

Abstract: A pneumatic tire comprising a carcass comprising a ply of cords defining the innermost reinforcing cord layer extending between bead portions, and an airtight layer disposed inside the cords of the carcass ply along the inner surface of the tire, covering the substantially entire inner surface of the tire, wherein the airtight layer is made of air-impermeable rubber including at least 10 weight % of halogenated butyl rubber and/or halogenated isobutylene-paramethyl styrene copolymer in its rubber base, and a thickness of the airtight layer measured from the inner surface of the tire to the cords of the carcass ply is in a range of from 0.2 to 0.7 mm.

Abstract: A pneumatic radial tire comprising an annular tread, a pair of sidewalls, an annular bead, a carcass, and an annular belt, when mounted on a standard rim to specifications and inflated with a standard pressure, staisfies the following condition:.theta.1.ltoreq.30 degrees and .theta.2.ltoreq.30 degrees, wherein .theta.1 and .theta.2 are the acute angles formed by lines P1 and P2, respectively, with respect to an imaginary straight line D which extends radially from the axial outer end point (62) of a rim flange (61) in a plane containing the rotating axis of the tire, the lines P1 and P2 being tangential to the outer surface profile (22) of either sidewall at points E1 and E2 where the outer surface profile (22) intersects with the straight line D.

Abstract: The invention relates to a pneumatic radial tire that has a tread of straight grooves of broad and narrow widths and which is adapted to insure sufficient rigidity in the tread to provide better steering stability. Tie bars are provided in straight sub-grooves of narrow width one of which is located between an inner middle block and an outer middle block, thereby reinforcing the acute-angled portions of the inner and outer middle blocks. Each tie bar consists of an inner tie bar with length L.sub.1 that extends in contact with the land angle of .alpha..sub.1 of the inner middle block and an outer tie bar with length L.sub.2 that extends in contact with the land angle .alpha..sub.2 of the outer middle block.

Abstract: A radial ply tire with a steel belt, which comprises a carcass ply turned up around bead cores from the axially inside to the outside thereof and a belt comprising two plies of parallel steel cords disposed radially outside the carcass ply in a tread portion of the tire, wherein the amount of steel included in the radially innermost belt ply per an axial unit width and a circumferential unit length there is less than that in the radially outer belt ply disposed on the radially outside of the innermost belt ply.