Patent ID: 9545823
Date: 2017-01-17
CPC Classifications: B60C

Claim:
1. A tire is provided having a circumferential rubber tread composed of a cap/base configuration comprised of an outer tread cap rubber layer with a lug and groove configuration with the outer portions of the tread lugs providing the running surface of the tread, and a tread base rubber layer underlying the outer tread cap rubber layer; wherein the outer tread cap rubber layer is composed of three circumferential load bearing zones comprised of an intermedial tread zone rubber layer positioned between and extending beneath two lateral tread zone rubber layers to thereby underlie the lateral tread zone rubber layers and overlay the tread base rubber layer to therefore stratify the lateral tread zone rubber layers as being separated from each other and from the tread base rubber layer; wherein outer surfaces of the tread lugs of the intermedial tread zone rubber layer and lateral stratified tread zone rubber layers comprise the running surface of the tread; wherein a peripheral rubber layer of the tread is provided which is comprised of a radial extension of a tire sidewall rubber layer containing at least about 40 phr of rubber reinforcing carbon black which extends radially outward from the tire sidewall to form a peripheral rubber layer of the tread which extends to and includes a portion of the running surface of the tire; wherein rubber composition of the intermedial tread zone rubber layer has a 100° C. hot rebound property greater than the 100° C. hot rebound property of the rubber composition of the stratified tread rubber layers; wherein the stratified lateral tread zone rubber layer composition has an at least 20 percent greater tear resistance property than the intermedial tread zone rubber layer composition and where the intermedial and stratified lateral tread zones are configured with lugs and intervening grooves with each stratified tread zone containing at least one tread groove; and wherein the rubber composition of the intermedial zone rubber layer and/or stratified lateral tread zone rubber layers are silica-rich in a sense of containing at least 40 phr of precipitated silica and a maximum of 30 phr of rubber reinforcing carbon black and thereby presenting a significant degree of insulative electrical resistance for the intermedial and/or lateral rubber layer zones so long as the 100° C. hot rebound property of the of the intermedial tread zone rubber layer is greater than the 100° C. hot rebound property of the rubber stratified tread zone rubber layers, wherein the peripheral carbon black-rich rubber sidewall extension provides a path of least electrical resistance between the tire carcass and tread running surface.