Pneumatic radial tire for winter season

摘要

PURPOSE: A pneumatic radial tire for the winter season is provided to secure braking force and driving force on a snowy road without inserting a spike pin, prevent partial side wear during traveling on a common road, and improve the life span of the tire. CONSTITUTION: In a pneumatic radial tire for the winter season, main grooves(G1,G2,G3) are circumferentially formed to a tread of the tire and lateral grooves(G4,G5,G6) are laterally formed, to constitute blocks(B1,B2,B3). A sipe(K) is inserted in each block. In inserting the sipe in the block, if the insertion depth is y and the depth of the main grooves is x, the pneumatic radial tire satisfies a formula where 0.4x is less than or equal to y and y is less than or equal to 0.8x.