Japanese Patent JPS6351882

B2

PURPOSE:To stabilize straight running performance by constituting a carcass cord of a radial tire of a lower layer wound up around a bead wire and an upper layer which is divided into a right and left portion and extends to the bead portion, and setting a width of overlap between the upper layer of the carcass cord and a belt reinforcing layer and an angle of a reinforcement cord to a predetermined value. CONSTITUTION:A carcass cord layer is constituted of a lower layer 4d continuously extending in a transverse direction and wound up around a bead wire and an upper layer 4u divided into a right and left portion and having a height from a bead toe to its end of not more than 0.3 times a height of a tire in section, wherein the upper layer 4u is disposed apart from the bead wire and is overlapped with a belt reinforcing layer 5 in the width of not less than 10mm.. Further, cord angles alpha1 and alpha2 of the carcass cord layers 4d and 4u forming a reinforcement cord for the belt reinforcing layer 5, which angles are measured from an acute angle side of a tire circumferential angle, are set to the range of 95 to 120 deg. at an average, and the difference be tween alpha1 and alpha2 is set to the range of 10 to 60 deg.. With this constitution, a ply stair may be reduced without deteriorating characteristics of the radial tire, thereby improving straight run ning performance and lightening tire weight.

KABE KAZUYUKI
MORIKAWA YASUO

JP9625382A

October 17, 1988

June 07, 1982

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YOKOHAMA RUBBER CO LTD

B60C9/08; B60C9/09

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