CASTER/WHEEL TERMINOLOGY
Anatomy of a Caster
The top plate is a flat plate atop the caster meant to be used to mount the caster to a piece of equipment.
The swivel head is a housing for the bearings to allow the caster to swivel.
The caster legs are two pieces of metal welded at a 90* angle to the swivel section to allow a wheel to be attached.
The axle is a bolt which passes through the caster and wheel to affix the two together.
The wheel is the part of the caster which comes into contact with the floor.
The overall height is measured from the top of the plate to the bottom of the wheel.
Anatomy of a Wheel
The tread is the outermost part of the wheel which comes into contact with the floor. Type of tread is important when choosing the right wheel for the job. Softer treads typically roll more quietly, but harder treads typically roll with less effort. The tread width is usually how a wheel's width is measured.
The core is the interior of the wheel. Some wheels are the same material between core and tread, others are two materials bonded together.
The hub is the center of the wheel which is typically reinforced and is normally wider than the tread. A bearing is usually inserted here. The hub length is a critical measurement needed in order to ensure a wheel will correctly fit into a caster.
The bore of the wheel is the hollow center through which an axle passes.
The wheel diameter is the measurement of the wheel from one side of the other in a straight line across the bore.