The subject invention discloses the use of syndiotactic-1,2-polybutadiene in the supporting carcass and/or innerliner of a tire. The incorporation of syndiotactic-1,2-polybutadiene into rubber compositions which are utilized in the supporting carcass or innerliner of tires greatly improves the green strength of those compositions. The incorporation of syndiotactic-1,2-polybutadiene into halogenated butyl rubbers which are utilized as innerliner compositions also greatly improves the scorch safety of such compositions. The subject invention more specifically discloses a pneumatic rubber tire which comprises a circumferential rubber tread, a supporting carcass therefor, two spaced beads, two rubber sidewalls connecting said beads and an innerliner; wherein said supporting carcass is comprised of from 1 to 25 phr of syndiotactic-1,2-polybutadiene having a melting point which is within the range of 120.degree. C. to 190.degree. C. and at least one rubber selected from the group consisting of polyisoprene, styrene-butadiene rubber, and polybutadiene rubber.