Abstract: A pneumatic tire wherein a plurality of righthand oblique groove groups each group of which has a plurality of righthand oblique grooves as extending obliquely to a reverse tire turning direction from a tread center portion to a righthand shoulder end and a plurality of lefthand oblique groove groups each group of which has a plurality of lefthand oblique grooves extending obliquely to the reverse tire turning direction from the tread center portion to a lefthand shoulder end are disposed alternately in a tire circumferential direction on a tread surface which has a tire turning direction designated in one direction in such a manner that one main rib is defined in a zigzag shape in the tire circumferential direction by starting end portions of the righthand oblique groove groups and by starting end portions of the lefthand oblique groove groups and lefthand and righthand sub ribs are branched from the main rib along the righthand oblique groove groups and the lefthand oblique groove groups, respectively.

Abstract: A pneumatic tire to be fitted on a wheel wherein a position, in which a disc is connected to a rim, is offset from the cneter of width of the rim toward the outer surface of the wheel, characterized in that a ratio (Ho/Hi) of an attenuation coefficient Ho (=Go.times.tan.delta.o) determined on the basis of an average thickness Go of an outer side wall of the tire on the outer side of the wheel and a loss factor tan.delta.o of the rubber of this side wall to that Hi (=Gi.times.tan.delta.i) determined on the basis of an average thickness Gi of an inner side wall of the tire on the inner side of the wheel and a loss factor tan.delta.i of the rubber of this side wall is set in the range of 1.2-6.5.

Abstract: In a pneumatic tire which is to be fitted to a wheel of the type in which connecting position of a disc to a rim is offsetted to a wheel outer side from a center of a rim width, and which has a plurality of blocks on a tread thereof, a pneumatic tire wherein a total contact area C.sub.2 of shoulder blocks on the tire outer side disposed on the offset side of the disc and a total contact area C.sub.1 of shoulder blocks on the tire inner side disposed on the opposite side to the offset side of the disc satisfy the relation, C.sub.1 /C.sub.2 =1.2 to 2.0.

Abstract: A pneumatic radial tire to be fitted on a wheel in which a position wherein a disc is joined to a rim is offset from the center of the width of the rim toward the outer surface of said wheel, characterized in that the tire comprises an asymmetric structure in which a belt layer is provided between a tread and a carcass layer, an outer circumferential portion of the belt layer being covered with at least one belt covering layer, the at least one belt covering layer being disposed so that an average position of the center(s) of the width(s) thereof from the equator of the tire is deviated toward the opposite side of the offset side of the disc, a ratio e/w of the deviating distance e to the width w of a ground contacting portion of the tread being set to 0.05-0.13.

Abstract: A pneumatic radial tire characterized in that at least two belt layers reinforced with cords of a high elastic modulus extending at an angle of 14.degree.-33.degree. with respect to the circumferential direction of the tire are arranged between a tread and a carcass, at least one of these belt layers being folded back at both end portions thereof toward the equator of the tire so as to wrap both end portions of any remaining belt layers, at least one reinforcing layer which is reinforced with thermally contractible organic fiber cords which extend at substantially 0.degree. with respect to the circumferential direction of the tire being inserted inside of each of the folded portions of the at least one folded belt layer, the width of the reinforcing layers being set to 10-70% of that of each of the folded portions.