Abstract: A heavy duty radial tire has a carcass including a carcass ply made of cords arranged at an inclination angle of 70 to 90 degrees with respect to the tire equator, the carcass ply including a main portion extending from a tread portion to a bead core in a bead portion and integrally provided with a turnup portion turned up from the axially inside to the outside at the bead core, a bead apex disposed between the main portion and turnup portion of the carcass ply, wherein the turnup portion extends radially outwardly along the axially outer surface of the bead apex and has a portion extending substantially parallel with and adjacent to the carcass ply main portion from the radially outer end of the bead apex, and the length L of the parallel portion is 1.0 to 8.0 times the maximum section width CW of the bead core.

Abstract: A pneumatic tire comprises a carcass ply extending between bead portions and is turned up around a bead core in each bead portion to form two turnup portions and a main portion therebetween; each of the turnup portions extends radially outwardly and adjoins the main portion from a certain height above the bead core; a space is surrounded by the carcass ply main portion, and each turnup portion and the bead core is filled with a small size bead apex rubber or a gas; and the bead portion is provided between the carcass ply and the bead core with a bead core cover for preventing the carcass cords from direct contacting with the bead core.

Abstract: A pneumatic tire comprises a breaker disposed radially outside a carcass and having a cord angle of not less than 10 degrees, and a band disposed between the carcass and the breaker and having a cord angle of less than 10 degrees, the breaker having a double-layered cord structure comprising a radially outer layer and a radially inner layer between which the cord inclination is reversed, the band being made of spiral windings of at least one cord; and the breaker is preferably formed by continuously winding at least one cord zigzag around the radially outside of the band plural times, in each turn the tape being bent at the axial edges of the breaker.

Abstract: A heavy duty radial tire is to be mounted on a 15 degree drop center rim. In a mounted state that the tire is mounted on the rim and inflated to 0.5 ksc but not loaded, the inside diameter BC of the bead cores at the radially innermost point thereof is set to being not more than the diameter BT at the heel point of the bead portions. In a demounted state that the tire is demounted from a rim, the bead bottom is tapered towards the axial inside of the tire at an angle .theta. of from 1.0 to 1.9 times the angle .alpha. of the tapered bead seat of the rim. In the mounted state, the bead core has a radially inner surface tapered at the substantially same angle as the bead seat, and the axial distance BP of the axially inner end of this tapered inner surface from the bead heel point is set in the range of from 1.3 to 2.1 times the maximum width BW of the bead core measured in the direction parallel to the bead seat.

Abstract: A snow tire which has tread blocks provided with slits extending between the side edges of the block, and the slit comprises: the first part extending axially of the tire from one side edge toward the other side edge of the block; the second part extending axially of the tire from the said other side edge toward said one side edge of the block; and the third part extending obliquely with respect to the tire axial direction to connect the first part with the second part, wherein the depth of the slit is varied in the tire axial direction to form a shallow portion and a deep portion, the axial length of the first part is more than 0.25 times and less than 0.48 times the total axial length of the slit, the axial length of the second part is more than 0.25 times and less than 0.48 times the total axial length of the slit, the ratio between the axial length of the first part to the axial length of the second part is more than 0.8 and less than 1.2, the axial length of the third part is more than 0.

Abstract: A radial tire provided with a circumferentially extending narrow groove in a boundary region between a tread portion and a buttress portion, and the narrow groove is inclined axially inward at the bottom by an angle of 0 to 5 degrees to the normal direction to the tread face, whereby the occurrence of vehicle wandering is effectively prevented without producing uneven wear in the tread shoulder regions.