Abstract:
The invention relates to a tire having a rubber tread comprised of cap/base construction where the tread cap layer provides the running surface of the tread and the tread base layer underlies the tread cap layer and thereby provides a transition between the tread cap layer and the tire carcass. For this invention, the tread cap layer is comprised of a plurality of individual circumferential load-bearing zones of rubber compositions, which exhibit graduated physical properties, and which extend from the outer running surface of the tread cap layer radially inward to said tread base layer. In one aspect, the zoned rubber tread cap layer and rubber tread base layer are co-extruded together to form a unit as an integral tread rubber composite.
Abstract:
The invention relates to a tire having a circumferential tread of a cap/base configuration composed of an outer tread rubber cap layer with a running surface of the tread and an underlying tread rubber base layer, wherein said tread cap layer is composed of two longitudinal adjacent zones, namely a primary tread cap zone and a minor lateral outboard control element (zone). The primary tread cap zone and the lateral outboard tread cap element provide a significant gradation of cold dynamic storage moduli (G′) at −25° C. and hot tan delta values at 100° C., yet similar warm dynamic storage moduli (G′) at 60° C. The primary tread cap zone and lateral outboard control tread cap element are load bearing in the sense of extending from the running surface of the tread radially inward to the unitary (non-zoned) tread base rubber layer. The zoned rubber tread cap layer and unitary rubber tread base layer are an integral tread composite in a sense of being co-extruded. In one aspect of the invention, the primary tread cap zone rubber composition is silica-rich and the lateral, outboard element rubber composition is carbon black-rich and which furthermore provide a gradation of filler reinforcement content; provide a gradation of silica to carbon black ratio and provide a gradation of cis 1,4-polybutadiene rubber content.
Abstract:
A pneumatic run-flat tire has a bead configuration wherein the axially inner end is radially inward of the axially outer end of the bead. The sidewall of the tire, from the bead region to the upper sidewall is reinforced to form a pillar support in the sidewall. The bead configuration and the pillar reinforcement enable the tire to lock itself onto a tire rim during low pressure operation and be self-supporting.