The feet of modern bed frames often have pre-drilled holes in the bottom that allow one to attach a wheel or roller known as a caster. Bed frame casters are round or barrel-shaped wheels with a stem on top that fits in the hole in a bed frame's foot. These casters allow one to move a bed by rolling it instead of dragging or lifting it. Casters make moving the bed easier and also raise the bed 1 inch (2.56 centimeters) or more, depending on the size of the caster used.
The size of bed frame casters generally is more important than their shape. Casters must support the weight of the bed's occupants, the frame, a mattress and box springs, when used. Casters that a manufacturer provides with a purchased bed frame normally are the correct size for the bed and frame they accompany. When replacing casters, one needs to buy the same size or larger to ensure that the casters can bear the weight of the bed.
Molded plastic is the most common material used for casters. This material choice creates a strong caster that is less likely to shatter under the weight of the bed and frame. Plastic also is durable and glides easily on floors.
Plastic casters also are a potential source of damage to floors and carpeting. Dust, lint and small dirt particles that the casters pick up while in use can gouge the surface of a smooth hard floor when one moves the bed. Casters also make dents or impressions on carpets and padding, because they push down carpet fibers.
One disadvantage of having casters on a bed frame is that they can cause the bed to move when one accidentally pushes it. Bed frame casters also might make the bed move when occupied and while one is getting in or out of bed. Buying locking casters is a popular solution for this problem.
Hardware and home improvement stores sell caster cups that help one reduce the potential damage to hard floors and carpet caused by bed frame casters. Caster cups designed for carpeting are plastic squares with slightly raised edges that keep the caster inside the cup. For hardwood and smooth floors such as tile, one typically uses rubber cups with a raised edge and ridges inside the cup. Both cup styles also decrease accidental shifting of the bed once inserted under the bed frame casters.