A tread for a heavy truck tire, comprising: an upper surface that is configured for engaging ground, wherein the tread has a radial direction , an axial direction , and a circumferential direction , wherein the tread is directional such that the tread is configured for having a rolling direction that extends in the circumferential direction; a J shaped sipe , comprising: a trailing edge , a leading edge , wherein the trailing edge is forward of the leading edge in the rolling direction; a main portion that extends from the upper surface, wherein the main portion has an opening at the upper surface and a bottom end opposite the opening in the radial direction; and a curved portion that extends from the bottom end of the main portion wherein the curved portion has a bottom curved wall that has a radius r 1 , wherein the curved portion extends from the bottom end of the main portion forward in the rolling direction, wherein the curved portion has a curved portion end , wherein the curved portion has a top curved wall that faces the bottom curved wall wherein the curved portion has a curved portion thickness t2 that is a distance from the top curved wall to the bottom curved wall and is less than or equal to 1 millimeter, characterized in that the curved portion has different cross-sectional sizes at different points along an axial width of the J shaped sipe such that the curved portion has at least one curved thicker gapped zone and at least one curved thinner gapped zone . an upper surface that is configured for engaging ground, wherein the tread has a radial direction , an axial direction , and a circumferential direction , wherein the tread is directional such that the tread is configured for having a rolling direction that extends in the circumferential direction; a J shaped sipe , comprising: a trailing edge , a leading edge , wherein the trailing edge is forward of the leading edge in the rolling direction; a main portion that extends from the upper surface, wherein the main portion has an opening at the upper surface and a bottom end opposite the opening in the radial direction; and a curved portion that extends from the bottom end of the main portion a trailing edge , a leading edge , wherein the trailing edge is forward of the leading edge in the rolling direction; a main portion that extends from the upper surface, wherein the main portion has an opening at the upper surface and a bottom end opposite the opening in the radial direction; and a curved portion that extends from the bottom end of the main portion wherein the curved portion has a bottom curved wall that has a radius r 1 , wherein the curved portion extends from the bottom end of the main portion forward in the rolling direction, wherein the curved portion has a curved portion end , wherein the curved portion has a top curved wall that faces the bottom curved wall wherein the curved portion has a curved portion thickness t2 that is a distance from the top curved wall to the bottom curved wall and is less than or equal to 1 millimeter, characterized in that the curved portion has different cross-sectional sizes at different points along an axial width of the J shaped sipe such that the curved portion has at least one curved thicker gapped zone and at least one curved thinner gapped zone . <EOS>