Abstract: The invention relates to an improved carbon black for tire tread rubber. More particularly, the invention relates to a carbon black which imparts upon tire tread rubber improved treadwear, lower rolling resistance, lower heat buildup and improved tear resistance. The improved carbon black is in the N100 series and, when in rubber, combines the long tread wear and low heat buildup advantages N121 carbon black with the high tear resistance properties of N115 or N110. The improved carbon black has particular application to truck and bus steel cord radial tire treads, especially for use in on/off highway conditions, and for high performance passenger car tires.

Abstract: A method of improving balance of properties, such as increased reinforcement and reduced rolling resistance of a rubber compound, comprising mixing the rubber compound with a carbon black and a silane coupling agent for a period of between about 10 seconds and 20 minutes at a temperature of between about 160.degree. C. and 180.degree. C. such as a styrene butadiene rubber compound, is disclosed. The method involves mixing the rubber compound "in situ" with a carbon black and Bis(3-triethoxysilylpropyl)-tetrasulfane at ambient temperature.