In after-sales inquiries regarding casters, one question arises extremely frequently:

“Why is only one of the four casters on the same piece of equipment severely worn?”

Many procurement professionals’ first instinct is to suspect a problem with the caster quality, so they replace the casters with new ones.

However, before long, the new wheels once again began to exhibit the same localized wear.

In fact, in the caster industry, this phenomenon is commonly referred to as “Eat the round” — Not all wheels wear evenly; rather, one or two casters show significantly faster wear than the others.

The real cause is often not the casters alone, but rather the combined effect of multiple factors, including the equipment’s load, installation method, and operating trajectory.

What is “eating the rotation”?

The so‑called “uneven wheel wear” refers to a situation in which, during prolonged operation, certain casters bear a significantly greater load, leading to abnormal wear.

Common manifestations include:

• The tread of one caster wheel has noticeably thinned;
• The degree of wear on the left and right sides varies significantly;
• The front tires wear out faster than the rear tires.
• Even after replacing the wheel with a new one, the same location still shows the earliest signs of damage.

If these conditions occur, it indicates that the entire mobile system should be inspected, rather than simply replacing the wheels.

Reason 1: The equipment’s center of gravity is not centered.

Many devices may appear symmetrical from the outside, but their internal weight distribution is uneven.

For example:

• The motor is mounted on one side;
• The battery pack is centrally arranged;
• The control cabinet is tilted to one side;
• Tools are kept in a designated area for the long term.

Over time, some casters consistently bear a heavier load and therefore wear out more quickly.

Therefore, following equipment design or modification, the weight distribution should be reassessed rather than assuming that the four casters share the load equally.

Reason 2: Long-term operation on a fixed route

Some devices follow the same route every day.

For example:

From the warehouse to the production line;

From the assembly area to the packaging area;

From the workshop to the loading dock.

If the path repeatedly passes through the same threshold, ramp, or turn, certain casters will continuously experience greater impact and lateral forces.

This repetitive operating condition causes wear to concentrate at a fixed location.

Therefore, the equipment’s operating path is also a key factor affecting the service life of casters.

Reason 3: There is an installation misalignment.

Although caster installation may seem straightforward, it actually requires a certain level of precision.

If the mounting surface is uneven, the mounting holes are misaligned, or the equipment base itself has undergone slight deformation, some casters may fail to make uniform contact with the floor.

The result is:

Some casters always bear the primary load;

Some casters simply “follow along.”

Over the long term, this will result in noticeable differences in wear.

Therefore, when replacing casters, you should also verify that the mounting surface is level, rather than focusing solely on the casters themselves.

Reason Four: Steering habits cause uneven tire wear.

Many factories have established transportation practices.

For example, always turning in the same direction; or operators habitually push the cart with one hand, causing the equipment to frequently drift to one side.

Prolonged repetition of these movements can cause certain casters to experience increased lateral friction over time.

In particular, with swivel casters, localized wear on the wheel surface becomes more pronounced during frequent sharp turns.

Reason 5: The casters were not replaced as a whole.

Many companies, in an effort to cut costs, adopt a “replace one when it breaks” approach.

This approach may be acceptable in certain situations, but if the diameter difference between the new and old casters is already quite pronounced, it could compromise the overall load distribution.

The new casters bear a greater load, while the old ones continue to wear down, resulting in increasingly uneven stress distribution.

Ultimately, not only does new wheel wear accelerate, but it may also compromise the equipment’s straight-line operation and stability.

For equipment operating at high frequency over long periods, it may be necessary, based on actual conditions, to assess whether group replacement is warranted in order to maintain overall consistency.

How can you tell if a device has already “eaten the wheel”?

During routine inspections, you can focus on the following key points:

• Are the tread surfaces of the four casters worn evenly?
• Is there a particular wheel whose color change is more noticeable?
• Whether the equipment exhibits slight deviation during operation;
• Whether a particular corner is noticeably sunken;
• Do you always replace the casters in the same position?

If the same issue occurs repeatedly at the same location, further inspection of the equipment’s structure is warranted, rather than simply replacing components.

How can we reduce the “eating wheel” phenomenon?

Improvements can be made in the following areas:

Properly position the equipment’s center of gravity.
Strive to maintain balanced weight distribution and avoid prolonged unilateral loading.

Optimize transportation routes.
Reduce frequent threshold crossings, sharp turns, and high-impact areas.

Rotate positions regularly.
For equipment that permits certain operating conditions, the caster positions may be adjusted as appropriate in conjunction with the maintenance schedule to ensure more uniform wear.

Strengthen routine inspections.
Promptly detect early‑stage issues such as uneven wear, loose installations, and frame deformation, preventing minor problems from escalating into major failures.

A detail that’s easy to overlook

Many companies treat casters as consumables, but they overlook the fact that casters also serve as an “indicator” of equipment condition.

Abnormal wear on a single caster often indicates that the equipment’s load distribution has changed.

If you simply keep replacing the casters without identifying the root cause, the new casters will likely experience the same issue.

Therefore, casters not only require maintenance but also merit being included as a key monitoring indicator in equipment health management.

Written at the end

The wear of casters is never random.

Every instance of eccentric wear and every premature failure reflects the actual operating conditions of the equipment.

Truly professional equipment management doesn’t mean fixing whatever breaks; rather, it involves analyzing the wear patterns of casters to uncover underlying issues in equipment design, installation practices, and user habits.