Marathon Industries 16 Knobby Flat Free Wheelbarrow Tire Type: Wheels & Tires Features: Perfect for contractor wheelbarrows Black in color, knobby tread 500-Pound load capacity Not for highway use; mounted on a steel rim with a 6-inch centered hub and 5/8-inch ball bearings Most common tire for 6 cubic foot wheelbarrows 15.5-inch tire diameter; weighs 7 pounds