A tire having a circumferential tread comprising: two shoulder ribs (112a,b); and at least one main rib (114a,b,c), wherein the two shoulder ribs (112a,b) and the at least one main rib (114a,b,c) form at least two shoulder grooves (108a,b), and wherein the two shoulder grooves (108a,b) each have a plurality of outboard walls, each disposed at a substantially constant angle from a base of the shoulder groove to a shoulder rib surface, and wherein the two shoulder grooves (108a,b) each have a plurality of inboard walls, including a first set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a first angle (β 1) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to a main rib surface and a second set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a second angle (β 2) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to the main rib surface different from the first angle (β 1), wherein each curved lateral groove divides a rib (114a, 114c) into circumferentially spaced-apart blocks, wherein each partial lateral groove divides a block into a first portion and a second portion.. two shoulder ribs (112a,b); and at least one main rib (114a,b,c), wherein the two shoulder ribs (112a,b) and the at least one main rib (114a,b,c) form at least two shoulder grooves (108a,b), and wherein the two shoulder grooves (108a,b) each have a plurality of outboard walls, each disposed at a substantially constant angle from a base of the shoulder groove to a shoulder rib surface, and wherein the two shoulder grooves (108a,b) each have a plurality of inboard walls, including a first set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a first angle (β 1) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to a main rib surface and a second set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a second angle (β 2) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to the main rib surface different from the first angle (β 1), wherein each curved lateral groove divides a rib (114a, 114c) into circumferentially spaced-apart blocks, wherein each partial lateral groove divides a block into a first portion and a second portion.. wherein the two shoulder grooves (108a,b) each have a plurality of outboard walls, each disposed at a substantially constant angle from a base of the shoulder groove to a shoulder rib surface, and wherein the two shoulder grooves (108a,b) each have a plurality of inboard walls, including a first set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a first angle (β 1) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to a main rib surface and a second set of inboard walls extending circumferentially between a curved lateral groove and a partial lateral groove and disposed at a second angle (β 2) relative to a plane parallel to the equatorial plane from the base of the shoulder groove to the main rib surface different from the first angle (β 1), wherein each curved lateral groove divides a rib (114a, 114c) into circumferentially spaced-apart blocks, wherein each partial lateral groove divides a block into a first portion and a second portion..