Patent ID: 6142200
Filing Date: 2000-11-07
Classification: B60C,Y10S

Abstract:
A pneumatic radial ply truck tire for use on steering axles of trucks, the tire having a tread, the tread having a tread non-skid depth, four circumferential grooves including two centerline grooves and two shoulder grooves, the four circumferential grooves dividing the tread into five rib parts, the tread also having lateral grooves extending across the five rib parts of the tread to form five rows of circumferentially-separated block elements including two shoulder rows, two riding rows and a center row, the tire being characterized by:the two centerline grooves and the two shoulder grooves each having top, middle and bottom portions,the top portions having straight sides each angled at a top angle with respect to one of radial lines extending from the edges of the grooves at the maximum groove width,the middle portions having straight sides each angled at a middle angle with respect to one of the radial lines extending from the edges of the grooves at the maximum groove width, the middle angles being greater than the top angles,the bottom portions being U-shaped with a bottom depth that is less than 15% of the tread non-skid depth, the U-shaped bottom portions of the two centerline grooves and the two shoulder grooves each having a bottom width and a bottom depth less than 2.0 mm;the lateral grooves extending across the two riding rows and the center row having top and bottom portions, the top portions having a first width and a first depth that extends to less than 20% of the tread non-skid depth, the bottom portions having a second width and a second depth that extends to at least 50% of the tread non-skid depth, the second width being less than 30% of the first width; and,the lateral grooves extending across the two shoulder rows having inside ends comprising top and bottom portions, the top portions having a first width and a first depth that extends to less than 20% of the tread non-skid depth, the bottom portions having a second width and a second depth that extends to at least 50% of the tread non-skid depth, the remaining parts of the lateral grooves extending across the two shoulder rows having a width equal to the first width of the top portions and a depth equal to the first depth of the top portions.