A heavy truck tire tread (12) is provided that has a partially hidden longitudinal groove (22) with an undersurface channel (24) engaged by a longitudinal sipe (26). The partially hidden longitudinal groove (22) has a surface opening (28) that extends from a surface of the tread to the undersurface channel (24). The tread (12) has at least one of two features. The first feature is that the surface opening (28) extends from the surface to the undersurface channel (24) at an angle to the thickness direction such that the surface opening (28) at the surface is forward of the surface opening (28) at the undersurface channel (24) in the rolling direction (20). The second feature is that a lateral sipe (32) engages the surface opening (28) so that the first end is at the surface opening (28), and the second end is forward of the first end in the rolling direction (20).