Polyurethane tread on cast lron wheels Axle Bore :1/2", Hub Length: 2-7/16", Bearing Size: ¾”Roller Bearing Wheel Diameter Ranges: 4"/5"/6"/8", Wheel Tread Width: 2” Durometer: 75 Shore A (+/-5), Temp Range: -40F to 180F Weight capacity ranges : 4"wheel: 800 lbs. 5"wheel: 1000 lbs. 6"wheel: 1200lbs. 8"wheel: 1500lbs. Size: 8"x2" Number of Wheels: 1