| 摘要 |
PURPOSE:To improve drainage property by providing a plural number of thin grooves along the peripheral direction of tire in the region of the predetermined ratio of wall face of a main groove in the peripheral direction which is formed on tread face. CONSTITUTION:A plural number of thin grooves 8 are formed along the peripheral direction of tire in the region of 80% or more of wall face of a main groove 7 in the peripheral direction which is formed on tread face of tire. The shape of cross section of the thin groove 8 is not limited particularly, but sine curve is preferable. Drainage effect is improved when it is formed in spiral shape so that it approaches the bottom of the main groove 7 gradually in the reverse direction to the direction of rotation of tire T. And, the effect is improved when the angle alpha which normal line H of the thin groove 8 forms for radial direction R is set to approximately 0 deg. to 10 deg.. |
