4 Inch Casters

Four-inch casters are standard on mobile workbenches, die carts, heavy-duty utility carts, welding tables, tool cribs, bin racks, and medium-weight manufacturing equipment. They are also popular in warehouse environments on order-picking carts and material staging racks. Any application in the 200-800 lb per caster range on typical industrial flooring is a strong candidate for 4 inch wheels.

Traditional kingpin casters use a single bolt to connect the swivel raceway to the top plate. Kingpinless casters eliminate this single point of failure by using an enclosed raceway design where the top plate and swivel are integrated. Kingpinless models resist impact damage, last significantly longer under heavy use, and resist swivel flutter in tow-line applications. They cost more upfront but reduce replacement frequency in demanding environments.

Individual 4 inch casters range from approximately 200 to 800 pounds of rated capacity depending on wheel material, bearing type, and fork construction. A set of four casters rated at 600 lbs each provides a gross equipment capacity of around 1,800 lbs after applying a standard 25% safety factor. For loads near the upper end, choose forged steel forks and precision bearings for maximum reliability.

Polyurethane-on-iron or polyurethane-on-aluminum wheels are the top choice for concrete floors. The polyurethane tread protects the floor surface, absorbs vibration, and resists flat-spotting under static loads, while the rigid core provides high load capacity and low rolling resistance. For wet environments, look for non-marking polyurethane or Mold-On rubber treads that maintain traction on damp concrete.