BIKER CHIC: Rebecca Minkoff is taking it to the bike line. The designer has teamed up with Bloomingdale’s on an exclusive bag, the Bike Share backpack. A portion of proceeds from all bag sales will go to charities dedicated to making streets safe for bikers in four designated cities: New York, Chicago, San Francisco and Washington, D.C. The charities are, respectively, the Safe Streets Fund, the Active Transportation Alliance, the San Francisco Bicycle Coalition and Silicon Valley Bicycle Coalition, and the Washington Area Bicyclists Association. The bag itself, done in nylon with leather trim, is designed with bikers in mind, and features a water bottle holder, built in cardholder, and a key clip. Retailing at $195, the backpack will be available at Bloomingdale’s beginning June 15. Additionally, Minkoff herself will be on hand at the store’s 59th Street flagship on June 19 to fete the collaboration and correlating window display.