| 摘要 |
PROBLEM TO BE SOLVED: To improve bead durability by making bead compression between a rim and a tire suitable, to improve the mounting performance of the rim while keeping a fitting force necessary for the rim J, to reduce weight, and to improve accuracy and workability in making bead apexes. SOLUTION: A bead core 5 made by winding a bead wire in the peripheral direction has a projection 10 projecting inward in the radial direction at the center of the direction of the width of the inner surface Si in the radial direction in the cross section and a depression 11 depressed inward in the radial direction at the center of the direction of the width of the outer surface So in the radial direction. The projection 10 has a smooth curved contour and the radius of curvature R of an arc curve which joins both ends 10e of the projection 10 in the direction of the width to a projecting end 10c in the radial direction is made W×0.35 to 2.0, where W is the width in the axial direction of the tire.
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