Abstract: A heavy duty radial tire includes a pair of shoulder portions tapered at an angle &agr; of from 40 to 50 degrees, a pair of zigzag main grooves extending circumferentially to form a pair of shoulder ribs, the shoulder ribs provided with lug grooves each having an axially inner end P1 terminated in the rib and an axially outer end opened at the tread edge TE, the bottom Ys of the lug grooves extending from the radially outer surface to the axially outer surface of the shoulder rib while inclining at an angle &bgr;, the height H1 of the tapered shoulder portion being in the range of from 50 to 67% of the depth Hg of the zigzag main grooves, the angle &agr; at the tread edge TE being larger than the angle &bgr; at the axially inner end P1, the distance LA between the axially inner end P1 and the zigzag main groove being in the range of from 0.95 to 1.

Abstract: A heavy duty radial tire has an aspect ratio of not more than 80% and comprises a radial carcass; a belt comprising a first ply, a second ply and a third ply disposed in this order from the radially inside to the outside; the second ply being widest and the axial width BW thereof being in the range of from 1.00 to 2.00 times the section height H of the tire; a first rubber thickness d1 measured from the first belt ply's edge to the carcass being in the range of from 1.0 to 5.0 mm; a second rubber thickness d2 measured from the third belt ply's edge to the second belt ply being more than the first rubber thickness d1; an axial distance W1 of the first belt ply's edge from the second belt ply's edge and an axial distance W2 of the third belt ply's edge from the second belt ply's edge satisfying the following condition: 0<=W1-W2<=5.

Abstract: A heavy duty radial tire comprises a radial carcass ply turned up around bead cores from the axially inside to outside of the tire, and a steel cord bead reinforcing ply disposed along the axially outer surface of the carcass ply turnup portion. The height of the carcass ply turnup portions is 1.5 to 3.5 times the rim flange height. The bead reinforcing ply extends so that the radially inner end is disposed on the radially inside of a straight line drawn between the axially inner extreme end and the axially outer extreme end of a bead core, and the radially outer end is spaced apart from the radially outer end of the turnup portion by a radial distance of from 5 to 20 mm. The radially outer ends of the turnup portions and the radially outer ends of the bead reinforcing plies are each covered with a cap made of hard rubber having a JIS-A hardness of 75 to 85 degrees.

Abstract: A heavy duty pneumatic tire having improved resistance to uneven tread wear includes a tread portion provided with an axially outer longitudinal main groove and an axially inner longitudinal narrow groove, each extending circumferentially about the tire to define a narrow rib therebetween, the axially inner edge of the narrow rib being chamfered by a slope. In the tire meridian section, the slope is straight or concave. The axial width of the axially inner longitudinal narrow groove is in the range of from 0.5 to 2.5 mm. The axial width (W3) of the slope measured between the upper and lower edges thereof is in the range of from 0.3 to 0.8 times the axial width (W2) of the narrow rib, and the radial height (H2) of the slope measured between the upper and lower edges is in the range of from 0.3 to 0.8 times the depth (H1) of the axially inner longitudinal narrow groove.

Abstract: A pneumatic tire comprises a bead core disposed in each of a pair of bead portions and a carcass ply turned up around the bead cores, wherein the bead cores are provided in the radially inner surface with a swell having a radius of curvature in the range of from 0.35 to 2.0 times the width of the bead core. The swell preferably extends all over the width of the bead core whereby no rubber layer is formed between the carcass ply and the radially inner surface of the bead core, and the contact pressure between the tire and rim is optimized.

Abstract: A pneumatic tire for a heavy load is provided which prevents irregular abrasion generated at the edge of land portions of the tire tread. An irregular abrasion preventing land portion is thus formed at the edge of a land portion, inside the shoulder edge of the tire, whereby the irregular abrasion generated at this portion is prevented.

Abstract: A pneumatic tire for a heavy load is provided which prevents irregular abrasion generated at the edge of land portions of the tire tread. An irregular abrasion preventing land portion is thus formed at the edge of a land portion, inside the shoulder edge of the tire, whereby the irregular abrasion generated at this portion is prevented.

Abstract: A heavy duty pneumatic tire, in which uneven tread wear is controlled, has a tread portion provided with a pair of main circumferential grooves so as to divide the tread portion into a pair of shoulder lands between tread edges and the main circumferential grooves and an axially inner land between the main circumferential grooves, each main circumferential groove having a width of from 4 to 12% of the tread width TW, a narrow circumferential groove extending circumferentially of the tire along one of the main circumferential grooves so as to divide the axially inner land into an axially outer narrow land part and an axially inner major land part, the axial width W1 of the narrow land part being in the range of from 0.1 to 0.2 times the axial width W2 of the major land part, the narrow circumferential groove having a width of 0.5 to 2.

Abstract: A radial tire is comprised of a belt, disposed between a carcass and a tread, having metal cord plies including a first belt ply, a second belt ply, a third belt ply and a fourth belt ply which are arranged radially outwardly in that order, wherein the second belt ply has a curvature concentric with the curvature of a radially outer surface of the tread and a width (B2) of at least 93% of the tread width (W), and the third belt ply has a width (B3) smaller than the width (B2) and is provided at both ends with spaced parts 1.5 to 4.5 mm distance apart from the second belt ply, the third belt ply, in a central part having a width (CR) of 60 to 70% of the width (B3) and both end parts each having a width (b) of 5 to 15% of the width, the third belt ply having a curvature concentric with the curvature of the radially outer surface of the tread.

Abstract: A heavy duty pneumatic tire having a tread provided on its outer surface with at least one circumferential groove. On the groove wall multiple projecting blocks are provided at an interval between the adjoining projecting blocks in the circumferential direction corresponding to 10-50% of the circumferential length of the projecting block and between the projecting blocks on the opposite groove walls a narrower groove is formed circumferentially having the open groove width corresponding to 5-50% of the open groove width of the above mentioned wider circumferential groove.