Patent ID: 6408908
Filing Date: 2002-06-25
Classification: B60C,Y10S

Abstract:
A pneumatic radial tire combination for four-wheeled automobile or light truck vehicles having a pair of front steer position tires and a pair of rear position tires, each tire having an axis of rotation and a casing, the casing having a carcass and a belt reinforcing structure radially outward of the carcass, a tread being radially outward of the belt structure, the tread having a pair of lateral edges, a tread arc extending between the lateral edges and a centerplane CP passing midway between the lateral edges and perpendicular to the axis of rotation, the tire combination hasa first tread arc for the front position tires and a second tread arc for the rear position tires, the tread arcs defined by a radially outer surface of the treads when the tires are normally inflated but unloaded, the first tread arc having on at least one-half of the tread at least three radii of curvature R1, R2, R3 decreasing in size as the curvature extends from the centerplane CP to the lateral edge, the radius R1 being a maximum radius at the centerplane of the tire and R2 and R3 being closer to the lateral edge than R1, characterized by at an intersection of the lateral edge and the tread arc a straight line drawn between the intersection of the tread arc curvature and the centerline CP is inclined at an angle &thgr;F relative to tangent line L, L being tangent to the tread arc at the centerline CP and parallel to the rotation, R1 being about 600 mm and greater than twice R3, R3 being greater than 200 mm and the lateral width of the tread of each front tire defined by a radius R1, radius R2 and radius R3 being less than 60% of said arc width, greater than 20% of said arc width and greater than 20% of said arc width, respectively; the second arc tread has a curvature of maximum radius R1 at the centerplane CP of the tire and has an angle &thgr;R of less than&thgr;F, &thgr;R being less than 5Â° relative to a tangent line L, L being tangent to the second tread arc curvature at the centerplane CP and parallel to the axis of rotation.