Tire with tread lugs extending in the sidewall made of rubber containing carbon black, starch and silica

This invention relates to a pneumatic rubber tire (1) having a circumferential rubber tread (2) of a lug (4) and groove (5) configuration which extends to a substantial portion an adjacent rubber sidewall (6) and is designed to be ground-contacting. Said lug and groove configured portion of said sidewall is of a rubber composition comprised of a blend of cis 1,4-polyisoprene natural rubber and cis 1,4-polybutadiene rubber which contains reinforcement as carbon black, starch/plasticizer composite and aggregates of participated silica together with a coupling agent. Said circumferential rubber tread (2) is of a rubber composition comprised of at least one diene-based rubber together with carbon black reinforcement and is exclusive of starch and precipitated silica.