PURPOSE: To improve bead durability by making sectional height of a folded part, sectional height of an inside rising part on a steel enforce, sectional height to the tire maximum width and sectional height of a rising part on abrasion rubber in a specified dimensional proportion.
CONSTITUTION: When sectional height of an end edge 10A of a folded part 10 on a radial carcass 9 is specified as A, sectional height of an inside rising part 11A on a steel enforce 11 as B, sectional height to the tire maximum width to be a bending point as C and sectional height of a rising part 7 on abrasion rubber 8 as D, C B A D is satisfied. A/C is made to be 40%-50%, and B/C is made to be 50%-60%. Consequently, even when a force from a road surface works on the end edge 10A of the folded part 10 on the carcass 9 as shear force, damage in the neighbourhood of the end edge 10A is certainly prevented and durability is improved.
MINEKAWA HIROSHI
ITO KUNIAKI
