JP2544553B

PURPOSE:To improve rim touch resistance without hurting durability, riding comfortableness, operating stability, and the like by specifying the outer skin sectional form of a tire. CONSTITUTION:In the meridian cross section of a tire in the normal internal pressure state, the ratio F/h is to be 0.092 or less, where F is the bead thickness at a bead inner surface point Pi where the tire radial reference line X passing a bead heel point PO intersects the inner surface of a bead part, and (h) is the tire radial distance from the rim flange upper end to a tire equator point C where the tread part outer surface intersects the tire equator face. The ratio R/h is to be 0.77 or more, wherein R is the radius of curvature of a circular arc L passing the thickness middle point Q1 of the bead thickness F, the thickness middle point Q2 of the tread thickness H at a tread inner surface point P2 where the reference line X intersects the tread part inner surface, and the thickness middle point Q3 of the side wall part thickness in the maximum width position of the tire.