Tire having tread with tread groove-containing rubber block joining the tire carcass and extending through a tread base into a tread cap

A pneumatic rubber tire having a circumferential tread of a cap/base construction comprised of an outer tread cap rubber layer containing a plurality of ribs containing tread running surfaces, with intervening grooves between the ribs, together with an underlying a tread base rubber layer;

• wherein said tire tread further includes at least one circumferential tread rubber block which contains at least a portion of at least one of said tread grooves including the bottom of the contained groove;
• wherein said tread groove containing rubber block joins the said tire carcass and extends radially outward through said tread base rubber layer and into said tread cap rubber layer, and contains the bottom and at least a portion of the walls of at least one of said grooves where said groove-containing rubber block:
• (A) extends within said outer tread cap rubber layer to include a portion of the outer tread running surface of at least one rib of said tread cap rubber layer, or
• (B) extends within said outer tread cap rubber layer without extending to a running surface of the tire tread;
• wherein the rubber compositions of the tread cap rubber layer, tread base rubber layer tire groove containing rubber block are comprised of individual sulfur cured diene elastomer-containing rubber compositions;
• wherein the rubber composition of the groove-containing tread rubber lock has a cut growth rate of at least 24 millimeters/minute less than the cut growth rate of the tread cap rubber layer which contains the encasement according to ASTM test D813 at 23° C.