Pneumatic tire with tread having center land and assistant grooves

A pneumatic tire having a tread surface,

• a first main groove extending in a circumferential direction of the tire being provided on each of right and left sides of an equatorial line of the tire in the tread surface, a second main groove extending in the circumferential direction of the tire being disposed on an outer side of the first main grooves in a widthwise direction of the tire, a center land being formed between the first main grooves, middle lands being formed between the first main grooves and the second main grooves, shoulder lands being formed outward of the second main grooves in the widthwise direction of the tire, sipes extending in the widthwise direction of the tire being disposed in each of the lands at prescribed intervals in the circumferential direction of the tire, lateral grooves extending in the widthwise direction of the tire being provided in the tread surface at prescribed intervals in the circumferential direction of the tire;
• wherein the middle lands each have an assistant groove less in width than the first and second main grooves, the assistant groove extending in the circumferential direction of the tire;
• the lateral grooves comprise right and left first lateral grooves and right and left second lateral grooves disposed on the right and left sides of the equatorial line of the tire, the right and left first lateral grooves extending from the center land outward in the widthwise direction of the tire beyond ground contact ends of the tire, the right and left second lateral grooves extending from the middle lands outward in the widthwise direction of the tire beyond the ground contact ends of the tire, the right and left first lateral grooves and the right and left second lateral grooves being alternately disposed in the circumferential direction of the tire;
• the right and left first lateral grooves have inner terminal ends which are disposed so as to be apart from each other in the center land, the right and left second lateral grooves having inner terminal ends which are located within the middle lands;
• and
• the tread surface has a ground contact surface region located between the right and left ground contact ends of the tire, the ground contact surface region having a center region portion on a center side thereof and side region portions located on opposite sides of the center region portion, a groove area percentage in the entire ground contact surface region being in a range of 18% to 33%, a groove area percentage in the center region portion being less than the groove area percentage in the entire ground contact surface region.