Heavy truck tire with shoulder rib sipe arrangement

A heavy truck tire tread having a longitudinal direction, a lateral direction and a thickness direction, said tread comprising:

• a shoulder edge;
• a shoulder groove;
• a shoulder rib defined between the shoulder edge and the shoulder groove, wherein the shoulder rib does not have any grooves;
• a plurality of sipes in the shoulder rib that extend from the shoulder edge to the shoulder groove, wherein the sipes are oriented in the shoulder rib so that either:
• (A) an average sipe line drawn from the intersection of the sipe and the shoulder edge to the intersection of the sipe and the shoulder groove is at an average sipe line angle to the lateral direction that is less than 20 degrees, or
• (B) an average sipe line drawn from a point of the sipe 8 millimeters inboard in the lateral direction from the shoulder edge to a point of the sipe 8 millimeters outboard in the lateral direction from the circumferential groove is at the average sipe line angle to the lateral direction that is less than 20 degrees;
• wherein the plurality of sipes has spacing in the longitudinal direction between successive sipes that is 5 to 18 millimeters, and wherein the plurality of sipes is provided such that every fourth sipe in sequence in the longitudinal direction extends a greater distance into the tread in the thickness direction than does the previous three successive sipes.

A heavy truck tire tread having a longitudinal direction, a lateral direction and a thickness direction, said tread comprising:

• a shoulder edge;
• a shoulder groove;
• a shoulder rib defined between the shoulder edge and the shoulder groove, wherein the shoulder rib does not have any grooves;
• a plurality of sipes in the shoulder rib that extend from the shoulder edge to the shoulder groove, wherein the sipes are oriented in the shoulder rib so that either:
• (A) an average sipe line drawn from the intersection of the sipe and the shoulder edge to the intersection of the sipe and the shoulder groove is at an average sipe line angle to the lateral direction that is less than 20 degrees, or
• (B) an average sipe line drawn from a point of the sipe 8 millimeters inboard in the lateral direction from the shoulder edge to a point of the sipe 8 millimeters outboard in the lateral direction from the circumferential groove is at the average sipe line angle to the lateral direction that is less than 20 degrees;
• wherein the sipe has a sipe bottom, wherein a reference plane lies in the longitudinal direction, wherein a sipe bottom point is located in the reference plane at the sipe bottom, wherein a sipe top point is located in the reference plane at the average sipe line, wherein a sipe inclination line extends from the sipe bottom point to the sipe top point, wherein a reference line extends in the thickness direction through the sipe bottom point and does not have a component in the longitudinal direction or the lateral direction, wherein the sipe inclination line is at a sipe inclination angle to the reference line, wherein the sipe inclination angle is greater than 0 degrees, wherein the sipe bottom point is configured to approach a contact patch before the sipe top point upon forward motion;
• wherein the plurality of sipes is provided such that every second sipe in sequence in the longitudinal direction extends a greater distance into the tread in the thickness direction than does the previous successive sipe.