15.5" Diameter, 8" Flat Free Wheelbarrow Tire, 4.80/4.00, Knobby Tread Great For Extra Traction, 6" Hub, 5/8" Ball Bearings, Solid, Lightweight Polyurethane Foam Tire Mounted On Steel Rim, Provides The Bounce & Feel Of Air Tires With The Benefit Of No Flats.