Pneumatic tire having a rubber component containing a block styrene butadiene copolymer

A pneumatic tire having a rubber component comprising a sulfur cured rubber composition composed of, based on 100 parts by weight of rubber (phr):

• (a) 99 to 50 parts by weight of a first rubber containing olefinic unsaturation;
• and
• (b) 1 to 50 parts by weight of a second rubber which is different from said first rubber and which is an elastomeric block copolymer of
• (1) from 15 to 65 percent by weight, based on the total block copolymer, of butadiene, and
• (2) from 35 to 85 percent by weight, based on the total block copolymer, of styrene, which block copolymer has:
• (a) at least two blocks A which have polymerized units of styrene, a glass transition temperature Tg above 25° C. and forms a rigid phase, and
• (b) at least one elastomeric block which is composed of about 25 to 70 percent by weight of butadiene and 75 to 30 percent by weight of styrene, and which has polymerized B/A units of styrene and butadiene in a random structure;
• a glass transition temperature Tg from −50° C. to 25° C., and is located between two blocks A and forms a flexible phase, and the amount of the rigid phase accounts for 5 to 40 percent by volume;
• said rubber composition further comprising from 0.5 to 20 phr of a sulfur containing organosilicon compound of the formula:
• Z-Alk-Sn-Alk-Z (15)
• in which Z is selected from the group consisting of
• where R1 is an alkyl group of 1 to 4 carbon atoms, cyclohexyl or phenyl;
• R2 is alkoxy of 1 to 8 carbon atoms, or cycloalkoxy of 5 to 8 carbon atoms;
• Alk is a divalent hydrocarbon of 1 to 18 carbon atoms and n is an integer of 2 to 8.