Abstract: A pneumatic tire having nominal rim size less than 762 mm (30 inches), flatness ratio less than 80% and a tread pattern including a plurality of lugs separated each other by a groove, said lugs comprising slanting portions which inclines relative to the equatorial line of the tire and extends from each side edge of the tread toward the each 1/4 position of the tread width and transverse portions which turns toward the equatorial line and terminates in the opposite area across the equatorial line, the transverse portion of the left-hand lug alternating with the transverse portion of the right-hand lug and overlapping each other in the circumferential direction of the tire, the groove edges being curved with the radius of curvature not exceeding 1 mm, overlapped ratio eP/Tw of the lugs being within the range of 0.30 to 0.38, the ratio Lt/2.times.Tw being 0.25 to 0.45, the coefficient of the projective length of the groove edges being 25 to 32, the ratio Ss/Sq of the sectional areas of the grooves being 1.