Pneumatic tire with tread having three dimensional sipes

A pneumatic tire comprising

• a tread portion having a plurality of blocks comprising a first block and a second block, said first block having a top face provided with a first three-dimensional sipe, said second block having a top face provided with a second three dimensional sipe,
• each of said first and second three-dimensional sipes extending along its longitudinal direction having an angle α in a range of from 0 to 45 degrees with respect to an axial direction of the tire,
• each of said three dimensional sipes having a first opening configuration that extends in a wavy manner having amplitude W and a cycle a1 in a cross sectional view of said block being parallel to the top face,
• each of said first and second three dimensional sipes having a second opening configuration that extends in a wavy manner having amplitude W and a cycle a2 in a cross sectional view of said block being perpendicular to the longitudinal direction, and
• each of said first and second three dimensional sipes satisfying the following relation in a rectangular coordinate system of x, y, z axes in which the x-axis corresponds to the longitudinal direction of each sipe, the z-axis corresponds to a depth direction of each sipe, and the y-axis is perpendicular to the x and y axes:
• y=W·sin {(2π·x/a1)+(2π·z/a2)},
• wherein said first block has a maximum axial block width in said blocks and said second block has a minimum axial block width in said blocks,
• the first three dimensional sipe of the first block has the cycle a2 larger than the cycle a2 of the second three dimensional sipe of the second block,
• the first and second three dimensional sipes differ from each other with respect to the cycle a2, and
• the first and second three dimensional sipes have the same cycle a1 and amplitude W.