PNEUMATIC RADIAL TIRE SUITABLE TO HIGH-SPEED DRIVING

PURPOSE:To improve high-speed durability without deteriorating maneuvering stability and partial wear resistance by positioning a central land part of a tread at a separate position within a particular range in the inside in the diametrical direction of a tire. CONSTITUTION:The tread of a pneumatic radial tire is blocked into two respective vertical block groups 6a, 6b and 7a, 7b on both sides toward tread edges T, and a rib 8 which forms a central part of the tread from peripheral grooves 1a, 1b and 2a, 2b which are mated on both sides of an equator O, a number of horizontal grooves 3a, 3b, 4a, 4b, and 5a, 5b whose tapered ends extend toward the equator O. With this constitution, in forming a tread pattern, the surface of the rib 8 is positioned more inwardly than the surfaces of the other land parts, that is, the surfaces of the vertical block grooves 6a, 6b and 7a, 7b in the diametrical direction of the tire. Namely, the rib 8 is formed so that its surface may be positioned more inwardly than the virtual outline L of the tread which connects the vertical block group 7a and 7b on both the sides, getting over the rib 8, so as to separate within the range of a distance h: 0.1-1.5 mm inwardly in the diametrical direction of the tire.