Pneumatic tire with tread having protrusions on bottom of grooves

A pneumatic tire having a tread area, the tread area being divided into a plurality of lands by virtue of a plurality of grooves extending in a tire circumferential direction and a plurality of grooves extending in a lateral direction, and each circumferentially extending groove having a bottom and a plurality of walls connecting the bottom of the circumferentially extending groove to the lands, the pneumatic tire comprising:

• a plurality of protrusions formed on the bottom of each of the circumferentially extending grooves and spaced from walls of the circumferentially extending groove, a height of the protrusion from the bottom of the circumferentially extending groove in a profile of the protrusion in a circumference direction of the pneumatic tire being variable, the protrusion including at least one peak portion that protrudes away from a center of the pneumatic tire;
• and
• each protrusion being directly connected to only one adjacent wall of the circumferentially extending groove by a connection member, the connection member having a first end connected to the adjacent wall and a second end connected to the peak portion,
• wherein a height of the first end from the bottom of the circumferentially extending groove is larger than a height of the second end from the bottom of the circumferentially extending groove, and a distance of the first end from the adjacent wall is smaller than a distance of the second end from the adjacent wall, and
• a location of each connection member in the circumferentially extending groove corresponds to a location of an intersection of the circumferentially extending groove and the laterally extending groove such that the connection member extends from the adjacent wall toward the laterally extending groove.