| 摘要 |
PURPOSE:To improve snow, noise and safe operation performances, by trisecting a tread portion with specific intervals by means of a pair of circumferential main grooves whose groove widths are predetermined, and forming a main groove as a continuation of a groove portion which is shifted in a tread width direction by a predetermined shift quantity. CONSTITUTION:A tread surface 2 is trisected by means of main grooves 3, 3 which are provided in parallel at an interval GD which is at the range of 0.2TW<=GD<=0.5TW against TW that is the maximum width of a tire. And, the groove width GW of each main groove 3 is set at the range of 0.02 TW<=GW<=0.07TW against TW that is the maximum width of the tire. In addition, each main groove 3 is formed as a continued groove having a zigzag quantity D that is smaller than the groove width GW, and its tread width direction shift quantity JW=GW-D is set at 0.5mm<=JW<=GW. As a result, snow, noise and safe operation performances can be improved. |
