⑤Types of Casters & Wheel Guide

Grainger Editorial Staff

Frequently Asked Questions

Q: What's the difference between caster brakes and caster locks?

A: Caster brakes and locks help control the mobility of the wheel in different ways:

        · A caster brake prevents the wheel from turning,          helping to keep the equipment in place. Caster            brakes are not designed to stop moving equipment 

          and are not intended to be used on ramps or              inclines.

        · A directional lock, also called a swivel lock,     prevents the caster wheel from swiveling while still       allowing it to roll, which is helpful for straight-line         travel.

        · A total lock prevents the caster wheel from                  swiveling and rolling, helping to immobilize the            equipment.

Q: What's the difference between pneumatic, semi-pneumatic and flat-free casters?

A: Pneumatic, semi-pneumatic and flat-free casters provide different levels of cushioning against shocks and vibration, and they also differ in their susceptibility to damage and their maintenance requirements:

         · A pneumatic caster wheel has a rubber tire filled        with pressurized air, making it more cushioned and      quieter, but also susceptible to punctures and flats.      Typically pneumatic wheels are used for low-speed      human-powered applications.

        · A semi-pneumatic caster wheel has a rubber tire         with thick walls around a non-pressurized pocket of     air, providing cushioning without the possibility of       going flat.

        · A flat-free caster wheel has a solid rubber or               polyurethane wheel that still provides some                 cushioning.

Q: Are forged wheels stronger than cast wheels?

A: To make cast iron wheels, the metal is heated until molten and poured into a mold to give it shape. To make forged steel wheels, the metal is heated until it is flexible but not molten, then shaped under intense pressure, cooled and machined into their final shape. Although cast metal wheels are very strong and durable, forged wheels are typically even stronger and more durable.

Q: What's the difference between starting resistance and rolling resistance?

A: When a cart is at rest and you want to get it moving, you are working against its starting resistance. When a cart is in motion and you want to keep it going, you are working against its rolling resistance. It's usually better for starting resistance and rolling resistance to be low because that means it take less effort to move the wheeled equipment around. In general, wheels that are larger and harder have lower starting and rolling resistance.

Q: What is a caster's swivel radius?

A: The swivel radius is a measurement indicating much space a caster needs for the wheel to fully swivel. To measure the swivel radius, start at the center of the kingpin or swiveling raceway, and measure the horizontal distance (in other words, parallel to the floor) between that point and the wheel's farthest edge.

（The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.）