Thrashin'

Thrashin' is a movie starring Josh Brolin, Robert Rusler, and Pamela Gidley. Two skateboarding gangs battle each other for supremacy, and a member of one gang falls in love with the sister of his rival.
Corey and his band of skater buddies sometimes make mischief, but they're more interested in girls and having fun on their boards than in getting into any real trouble. Notorious enemy crew the Daggers, led by Tommy Hook, get their kicks terrorizing the locals at Venice Beach. When Corey starts dating Tommy's kid sister Chrissy, the Daggers are furious. The boys then take their beef to the "L.A. Massacre," a deadly skate race down a canyon road.