Cargo or sport utility bikes are an emerging category. These two-wheeled pickup trucks feature oversized, reinforced racks and an extended wheel base for strength and stability. “Cargo bikes allow you to carry heavy loads without starting your car,” says Benjamin Sarazin, founder of Yuba Bikes in Sausalito, Calif. The fledgling company sold out its first shipment of 100 Mundo utility bikes in three weeks; buyers included a gardener, a baker and a campground in Maine.