When industrial casters fail, we typically focus on obvious issues such as tread wear, frame deformation, and bearing seizure. However, there is another rather unusual failure mode observed in the field:

The wheel appears to still turn, and the tread has not completely detached; however, as soon as the equipment is loaded or subjected to a significant thrust, relative slippage occurs between the tread and the wheel hub.

In mild cases, there may only be occasional unusual noises or asynchronous rotation; in severe cases, the wheel hub has already turned, while the outer wheel surface fails to move in sync.

This phenomenon can be understood as “slippage” occurring between the wheel tread and the wheel hub.

It is not entirely the same as the common adhesive‑coated delamination; what deserves even greater attention is: Can the force be reliably transmitted between the wheel tread and the wheel hub?

1. The wheel tread and the wheel hub are inherently designed to work together.

Many industrial casters are not manufactured as a single-piece unit from a single material.

For example, some rubber‑coated wheels use a relatively robust wheel core as their internal structure, with a surface material of specific properties applied to the exterior.

When the equipment moves, the ground’s reaction force on the wheel tread must be transmitted through the tread to the wheel hub, and then via the axle and support structure to the equipment.

Therefore, although the wheel tread and the wheel hub are distinct components, they must function as a single integrated unit.

If the force cannot be reliably transmitted between the two, a certain situation may arise:

On the outside, it still looks like a complete wheel, but inside, it’s already “out of sync.”

II. Why does the no-load test appear normal, only to reveal issues after loading?

This is precisely where such problems are most prone to misjudgment.

After lifting the equipment, manually rotate the casters; the wheels may turn very smoothly, with no obvious abnormalities apparent.

However, when idling manually, the required torque is very small.

Once the equipment is fully loaded, more pronounced forces must be transmitted between the wheel tread and the wheel hub during startup, turning, and when passing through areas with significant resistance.

If the internal bonding state has already become abnormal, the issue often only becomes apparent at this stage.

Therefore, caster testing cannot remain indefinitely at:

“It feels smooth when you pick it up and give it a spin.”

The ability to rotate under no-load conditions and the ability to operate reliably under load are two distinct issues.

III. How can you determine whether there is relative slip between the wheel tread and the wheel hub?

On-site, you can first observe several typical phenomena.

For example, when the equipment starts up, the wheels experience abnormal jerks.

There is a suspicious relative displacement between the wheel tread and the wheel hub.

Abnormal friction noises occur when the wheel is in operation;

The wheel tread shows no obvious damage, but its actual operating condition is unstable.

During maintenance, simple reference marks can also be made at corresponding locations on the wheel tread and wheel hub, followed by in-service observations under safe conditions.

If the relative positions of the last two markers change after running, it indicates that slippage may have occurred between the two parts.

Compared with manually turning the wheel, this type of inspection makes it easier to detect hidden issues.

IV. What factors may influence the binding state?

Such issues cannot be simply attributed to a single cause.

For composite‑structure casters, the wheel tread material, the wheel core material, the design of the bonding interface, and the manufacturing process can all influence the final performance.

After casters are put into service, factors such as long-term loading, frequent start–stop cycles, repeated steering, environmental media, and temperature fluctuations may also need to be investigated.

Therefore, once relative slip is detected, it is best to review both directions simultaneously:

The product’s inherent bonding state, as well as the long-term operating conditions experienced on site.

Focusing on only one side may lead to overlooking the true cause.

V. Why are equipment with frequent start–stop cycles more worthy of attention?

When the equipment moves at a constant speed, the casters remain in a relatively continuous rolling state.

However, at the moment of startup, the equipment must transition from rest to motion; frequent stops and restarts mean that this state is repeatedly cycled.

If weak spots already exist in the interface between the wheel tread and the wheel hub, repeated loading may cause these abnormalities to gradually become apparent.

For high‑frequency shuttle carts, production‑line material carriers, and automated handling equipment, it is not sufficient to simply track how far they travel each day.

Sometimes, The number of times the system was started and the number of steering maneuvers performed in a single day are equally worth monitoring.

6. If slippage is detected, can the product still be used?

If significant relative slippage between the wheel tread and the wheel hub has been confirmed, it is not advisable to simply treat it as ordinary wear and continue using it.

Because this means that the structure of the casters, which was originally intended to function as a unified whole, has already been altered.

Continuing to run may further exacerbate the scope of the exception and could also affect the device’s normal operation.

In particular, equipment subjected to high loads or frequent use should be inspected and replaced promptly, with any defective casters retained for subsequent analysis.

7. During failure analysis, don’t be quick to discard the defective wheel.

When this rare fault occurs, the faulty wheel itself constitutes highly valuable information.

It can record the installation location, equipment load, usage frequency, primary operating routes, and the phenomena observed before and after the occurrence of abnormalities.

If conditions permit, further inspect the actual condition of the interface between the wheel tread and the wheel hub.

If similar issues arise with other casters from the same batch, these records can help determine whether the problem is an isolated, one-off anomaly or stems from shared operating conditions or structural factors.

Written at the end

Industrial casters may appear structurally simple, but their actual motion is achieved through the coordinated interaction of multiple components.

The wheel tread is responsible for contact with the ground, the wheel hub provides internal support, and the interface between the two ensures reliable transmission of forces.

Therefore, to determine whether a caster is functioning properly, you cannot rely on just:

“Did the wheel rim fall off?”

Also worth noting:

“Are the wheel tread and the wheel hub still working together?”

Some faults occur on the surface and are immediately visible; others, however, are hidden inside the wheel and only become apparent during actual loaded operation.