A tire comprising: a tread portion comprising a tread edge (Te) and a tire equator (C), the tread portion being provided with a circumferentially and continuously extending main groove arranged between the tread edge (Te) and the tire equator (C) to define a first land portion between the main groove and the tread edge (Te); the main groove comprising a groove bottom having a deepest depth, an outer groove wall extending radially outwardly and inclined toward the tread edge (Te), and an inner groove wall extending radially outwardly and inclined toward the tire equator (C); the groove bottom extending in a zigzag manner in a tire circumferential direction in such a manner as to alternate between a first location where the groove bottom is located nearest to the tire equator (C) and a second location where the groove bottom is located nearest to the tread edge (Te); an angle θ2b with respect to a tire normal line of the outer groove wall in a groove cross-section at the second location being greater than an angle θ1a with respect to a tire normal line of the inner groove wall in a groove cross-section at the first location , and characterized in that the main groove comprises a pair of groove edges extending parallel with the tire circumferential direction, and the groove bottom extends oscillating in a tire axial direction with an amplitude (L2) of from 0.15 to 0.40 time a groove width of the main groove, wherein the amplitude (L2) refers to an axial distance of the oscillating groove bottom between the first location and the second location . a tread portion comprising a tread edge (Te) and a tire equator (C), the tread portion being provided with a circumferentially and continuously extending main groove arranged between the tread edge (Te) and the tire equator (C) to define a first land portion between the main groove and the tread edge (Te); the main groove comprising a groove bottom having a deepest depth, an outer groove wall extending radially outwardly and inclined toward the tread edge (Te), and an inner groove wall extending radially outwardly and inclined toward the tire equator (C); a groove bottom having a deepest depth, an outer groove wall extending radially outwardly and inclined toward the tread edge (Te), and an inner groove wall extending radially outwardly and inclined toward the tire equator (C); the groove bottom extending in a zigzag manner in a tire circumferential direction in such a manner as to alternate between a first location where the groove bottom is located nearest to the tire equator (C) and a second location where the groove bottom is located nearest to the tread edge (Te); an angle θ2b with respect to a tire normal line of the outer groove wall in a groove cross-section at the second location being greater than an angle θ1a with respect to a tire normal line of the inner groove wall in a groove cross-section at the first location , and the main groove comprises a pair of groove edges extending parallel with the tire circumferential direction, and the groove bottom extends oscillating in a tire axial direction with an amplitude (L2) of from 0.15 to 0.40 time a groove width of the main groove, wherein the amplitude (L2) refers to an axial distance of the oscillating groove bottom between the first location and the second location . <EOS>