24 define lateral grooves 10 which have a bottom surface indicated at 25 in accordance with the invention as shown particularly in fig2 tie bars 16 and 17 both of which extend circumferentially between adjacent tread blocks 9 in their respective ribs 3 have tapered top surfaces 27 and 28 respectively which are sloped in opposite directions with respect to each other top surfaces 27 and 28 preferably will be smooth continuous surfaces but could vary without effecting the invention tie bars 16 and 17 are similar to each other with the exception of the opposite direction of sloped top surfaces each tie bar includes spaced preferably parallel side surfaces 29 and 30 which preferably extend generally radially inward from the sloped top surface each tie bar is molded integrally with the adjacent tread block and bottom surface 25 of groove 10 during the molding of the tire tread thus molding of the tire requires only minor modifications to the mold such as removing material from the mold for forming the tie bars fig2 and 4 show one configuration of tie bars 16 and 17 wherein top surfaces 27 and 28 extend at equal angle of generally 45 u00b0 with respect to bottom groove surfaces 25 and only partially across the axial width of the adjacent.