Truck racing tire

Abstract

The invention is directed to a pneumatic radial ply truck tire having a tread with a tread depth D, at least two circumferential grooves dividing the tread into at least a first shoulder circumferential rib, an intermediary circumferential rib, and a second shoulder circumferential rib, the tire being characterized by the tread having a base region disposed at depth D and a cap region over the base region, the base region and the cap region adjoining along a boundary, the cap region comprising a cap rubber composition having properties measured at 23° C. of: elongation of 400 to 500%, true tensile of 77 to 83 MPa, 300% modulus of 9 to 11 MPa, tensile strength of 14 to 15 MPa, shore A hardness of 63 to 68, rebound of 20 to 25%; and the base region comprising a base rubber composition having properties measured at 23° C. of: elongation of 470 to 520%, true tensile of 135 to 150 MPa, 300% modulus of 13 to 15.5 MPa, tensile strength of 22 to 25 MPa, shore A hardness of 63 to 67, rebound 50 to 55%.

1 . A pneumatic radial ply truck tire having a tread with a tread depth D, at least two circumferential grooves dividing the tread into at least a first shoulder circumferential rib, an intermediary circumferential rib, and a second shoulder circumferential rib, the tire being characterized by: the tread having a base region disposed at depth D and a cap region over the base region, the base region and the cap region adjoining along a boundary, the cap region comprising a cap rubber composition having properties measured at 23° C. of: elongation of 400 to 500%, true tensile of 77 to 83 MPa, 300% modulus of 9 to 11 MPa, tensile strength of 14 to 15 MPa, shore A hardness of 63 to 68, rebound of 20 to 25%; and the base region comprising a base rubber composition having properties measured at 23° C. of: elongation of 470 to 520%, true tensile of 135 to 150 MPa, 300% modulus of 13 to 15.5 MPa, tensile strength of 22 to 25 MPa, shore A hardness of 63 to 67, rebound 50 to 55%.  
     
     
         2 . A tire according to  claim 1  further characterized in that at least one groove has a wear indicator formed therein at a preselected depth.  
     
     
         3 . A tire according to  claim 2  further characterized in that the boundary between the base region and the cap region is substantially at the preselected wear indicator depth within the one groove.  
     
     
         4 . A tire according to  claim 3  further characterized in that at least one tread region has at least one notch formed therein extending to the preselected wear indicator depth.  
     
     
         5 . A tire according to  claim 1  further characterized by at least one belt reinforcement structure located radially from the tread, the belt reinforcement structure comprising three belts.  
     
     
         6 . A tire according to  claim 5  wherein the nominal distance between the tread and an uppermost belt ranges between 2 and 5 mm.  
     
     
         7 . A tire according to  claim 1  wherein further characterized by a plurality of elongate notches formed to extend into the tread first shoulder rib, second shoulder rib, and intermediary rib in respective circumferential patterns.  
     
     
         8 . A tire according to  claim 7 , wherein further characterized by the circumferential patterns of first shoulder rib, the second shoulder rib, and the intermediary rib are mutually distinctive.  
     
     
         9 . A tire according to  claim 7  wherein the notches in the second shoulder rib extend at an oblique angle relatively to the equatorial plane of the tire.  
     
     
         10 . A tire according to  claim 7  wherein the notches in the first shoulder rib extend substantially normal to the equatorial plane of the tire.  
     
     
         11 . A tire according to  claim 7  wherein a plurality of notches extend to the boundary depth D of the tread.  
     
     
         12 . An asymmetric pneumatic radial ply truck tire having a tread with a tread depth D, at least two circumferential grooves dividing the tread into at least a first shoulder circumferential rib, an intermediary circumferential rib, and a second shoulder circumferential rib, the tire being characterized by 
 the first shoulder rib having width wider than the second shoulder rib and a substantially rounded upper surface across an outer edge region;    the second shoulder rib having a substantially flat upper surface across an outer edge region; and    the tread having a first wear indicator disposed within at least one circumferential groove and a second wear indicator disposed within a rib for confirmation of tread wear.    
     
     
         13 . A tire according to  claim 12 , wherein further characterized by the second wear indicator comprising a tread base region disposed at depth D constructed from relatively harder material and a cap region over the base region constructed from relatively softer material, the base region and the cap region adjoining along a boundary.  
     
     
         14 . A tire according to  claim 13 , wherein the first wear indicator within the at least one groove is at the depth of the boundary between the base region and the cap region.  
     
     
         15 . A tire according to  claim 12 , wherein further characterized by the second wear indicator comprising at least one notch formed to extend into at least one rib to a depth substantially corresponding to the depth of the first wear indicator.  
     
     
         16 . A tire according to  claim 12 , wherein further characterized by at least one belt reinforcement structure located radially from the tread, the belt reinforcement structure comprising three belts.  
     
     
         17 . A tire according to  claim 12 , wherein further characterized by the first shoulder rib having a substantially rounded upper surface across an outer edge region and the second shoulder rib having a substantially flat upper surface across an outer edge region.  
     
     
         18 . A tire according to  claim 12 , wherein further characterized by a plurality of elongate discrete notches formed to extend into the tread first shoulder rib, second shoulder rib, and intermediary rib in respective circumferential patterns.  
     
     
         19 . A tire according to  claim 18 , wherein further characterized by at least one notch in each circumferential pattern extends to a depth corresponding with the depth of the first wear indicator within the at least one circumferential groove.  
     
     
         20 . A tire according to  claim 1  further characterized in that the first shoulder rib has a width wider than the second shoulder rib and a substantially rounded upper surface across an outer edge region; and the second shoulder rib has a substantially flat upper surface across an outer edge region.