Heavy duty pneumatic tire

A heavy duty pneumatic tire comprising a tread portion provided with only three circumferentially continuous grooves, which are:

• a circumferentially continuous crown main groove extending zigzag along the tire equator and
• a circumferentially continuous shoulder main groove extending zigzag and disposed on each side of the crown main groove
• so that a pair of crown land portions are formed between the crown main groove and the shoulder main grooves, and a pair of shoulder land portions are formed axially outside the shoulder main grooves, respectively,
• wherein
• each of the crown land portions is only provided with wider crown lateral grooves and narrower crown auxiliary grooves,
• each of the shoulder land portions is only provided with shoulder lateral grooves,
• the crown lateral grooves in each of the crown land portions extend between the crown main groove and the shoulder main groove so that the crown land portion is divided into circumferentially arranged crown blocks,
• wherein
• the crown lateral grooves in each said crown land portion extend from alternate axially inside zigzag vertices of the shoulder main groove to zigzag vertices of the crown main groove, while inclining with respect to the tire circumferential direction,
• each said crown block is provided with one of the crown auxiliary grooves so as to extend to one of the zigzag vertices of the crown main groove to which none of the crown lateral grooves are connected, from one of the inside zigzag vertices of the shoulder main groove, while inclining with respect to the tire axial direction,
• the crown auxiliary grooves are narrower in width than the crown main groove,
• the shoulder lateral grooves in each of the shoulder land portions extend axially inward from a tread edge and terminate within the shoulder land portion,
• the crown lateral grooves each have a substantially constant width,
• the crown auxiliary grooves each have a substantially constant width, and
• a circumferential length of the crown auxiliary groove is more than a circumferential length of the crown lateral groove.