Abstract: A truck steer tire 10 has a wide decoupling groove 24 that extends inwardly from the tread in a circumferentially continuous fashion. The decoupling groove 24 extends between the tread surface 26 and the belt reinforcing structure 15. The decoupling groove 24 has a width in the range of 4 to 7 mm and a groove bottom having a full radius of curvature RG, RG being at least 2.5 mm. The decoupling groove 24 has a point C, C being centered on the bottom of the full radius of curvature RG, a line K drawn through the center C and the axially outermost end of the belt layers measures at least 10 mm and each axially outer end of the remaining belt layers is spaced greater than 10 mm from the center C.