Casters, heavy duty and light duty often have a common problem with vehicles that have caster wheels and is a type of instability that occurs most often when a vehicle is turning. Most of us have experienced caster flutter in the grocery store when we select a cart with a loose or loud wheel, or one that is difficult to steer. The problem occurs when the caster wheel starts to wobble and causes the shopping cart to shake.

Mechanically, caster flutter is caused by the caster angle changing as the wheel turns, which causes the wheel to oscillate. Caster flutter not only affects the steering of a vehicle, in a warehouse or industrial setting it is dangerous because it can cause the wheel to lose contact with the ground, which can lead to a loss of control. It can also be costly, because the instability of the vehicle caused by caster flutter may break or seriously damage fragile and expensive equipment being transported.

What Causes Caster Flutter

Caster flutter often occurs when a caster is subject to high loads and/or speeds. When this happens, the caster will start to sway back and forth, which can lead to instability and eventually failure. There are several specific causes of caster flutter, but the most common are loose caster wheels, casters mounted incorrectly, bent caster legs, and improper caster design. The good news is that there are ways to correct each of these problems.

Loose Caster Swivels

Uncontrollable fluttering can occur if the caster is too loose. The swivel should be tight enough so the caster (whether it is a light duty or heavy duty caster) will not move when the load is removed, but loose enough so the caster can turn smoothly. A swivel that is too tight will cause excessive friction and damage the swivel, casters or frame.
Casters Mounted Incorrectly

If casters are mounted incorrectly, they can cause caster flutter. This is because the caster assembly is not able to rotate properly, which causes it to vibrate. This can lead to the caster becoming unstable and eventually collapsing. If the assembly is mounted incorrectly, it can lead to the caster or load being damaged. For example, if a caster is mounted with its axis pointing toward the direction of travel and the load is pushed over an uneven surface, the irregular motion will cause vibration that can damage the caster (heavy duty caster or light duty caster), the load, or both.

Bent Light and Heavy Duty Casters Legs

Bent caster legs are a common cause of caster flutter. When the legs are bent, they create a rocking motion that can cause the caster to lose contact with the ground. When the legs of the caster are not perfectly straight, they can cause the caster to vibrate when in operation. This vibration can eventually lead to the caster failing and breaking. To avoid this, it is important to ensure that the legs of your caster are always straight.

Improper Caster Design

Another primary cause of caster flutter is improper design of the caster system, especially in machinery with heavy duty casters. The caster system must be designed so that the caster wheel and the swivel assembly are concentric. In addition, the caster system must be constructed so that the kingpin is perpendicular to the ground. Improper system design can lead to increased friction and wear, which can eventually cause the caster wheel to become unstable and flutter.

Reducing Flutter in Light and Heavy Duty Casters

While caster flutter is frequently serious, and always frustrating, it can be mitigated with a few easy fixes.

You can reduce or minimize caster flutter by:

• Using a longer kingpin.
• Reducing the caster angle by using narrower caster wheel.
• Improving friction by applying a dry lubricant (e.g., talcum powder) to the swivel assembly.
• Using a larger bearing.
• Increasing the distance between the axle and the top of the plate.

Conclusion

Caster flutter is a type of instability that can occur in caster-type steering systems. To avoid caster flutter, make sure that your caster wheels are properly adjusted and that the casters are mounted correctly. If your steering system is experiencing caster flutter, you may need to replace the wheels or legs.

If you need help fixing or replacing your caster, our expert team is here to help so please feel free to contact us with any questions or concerns.