Polyurethane casters combine wear resistance, load-bearing capacity, and a degree of floor protection, making them widely used in industrial pallet trucks, logistics equipment, and production tooling. However, with prolonged use, some casters may develop cracks on the tread, edge lifting, or even gradual delamination between the polyurethane layer and the wheel core. On-site, this phenomenon is commonly referred to as “debonding.” In fact, delamination is rarely due solely to material aging; it is typically influenced by factors such as bonding conditions, applied loads, impact, environmental media, and operating practices.

First, where exactly does “degumming” occur?

Rubber‑coated casters typically consist of an outer tread and an internal wheel core. Under normal conditions, these two components must remain securely bonded to ensure the smooth transmission of loads and rolling forces. When localized delamination occurs at the interface, the outer tread may undergo additional deformation during rolling, and the separation zone will gradually expand. In the early stages, this may manifest as narrow gaps along the edges; with continued use, it can progress to noticeable warping, bulging, or partial detachment.

II. Why does frequent starting and stopping make problems more apparent?

During equipment startup and braking, the wheel tread not only bears vertical loads but also experiences forces acting along the direction of rolling. For shuttle cars, traction bogies, and production-line equipment that undergo frequent starts and stops, these repeated cyclic loads are continuously transmitted to the interface between the wheel tread and the wheel core. If there is already localized insufficient bonding, or if the equipment operates under high‑load conditions for extended periods, such issues are more likely to become apparent over time. Therefore, when assessing the cause of delamination, it is essential to consider not only the weight of the equipment but also its daily operating patterns and movement characteristics.

3. Ground impacts can also accelerate stress on the interface.

Thresholds, floor joints, small steps, and damaged flooring can all subject wheels to sudden impacts. When the wheel tread encounters an obstacle, localized compression and deformation occur, with the resulting forces transmitted to the wheel hub. If the equipment operates at high speeds, carries heavy loads, or repeatedly traverses the same obstacle, the interface between the tread and the hub is subjected to more complex cyclic stresses. Optimizing the travel path and controlling the speed at which obstacles are negotiated can sometimes be more effective than simply replacing the wheels with harder ones.

4. Oil contamination, cleaning agents, and temperature conditions must also be taken into account.

Industrial environments are not always dry, at room temperature, or clean. Wheels may come into contact with oil, water, cleaning agents, or other substances, and they may also operate in areas subject to significant temperature fluctuations. Different materials exhibit varying degrees of environmental resistance; prolonged exposure to unsuitable media can compromise the wheel tread or the bond between components. Therefore, when placing an order, it is essential to proactively disclose whether the site involves chemical exposure, wet‑cleaning conditions, or extreme temperatures—rather than simply providing dimensions and load ratings.

V. What should be checked when early signs appear?

During routine inspections, pay particular attention to the junction between the wheel tread and the wheel hub for any abnormal gaps, edge lifting, bulging, or irregular cracks. When rotating the wheel, observe whether the tread exhibits noticeable runout or localized deformation. Even if only minor abnormalities are detected, prolonged operation under such conditions is not recommended. Instead, assess the situation in conjunction with the equipment’s load, the condition of other casters, and the on-site operating route to determine whether the issue is isolated to a single caster or indicative of a common operational problem affecting the entire batch.

VI. Why can’t it be simply attributed to “polyurethane being bad”?

Polyurethane is merely a material category; the actual performance of casters is also influenced by factors such as formulation, wheel core structure, molding process, surface treatment, and operating conditions. Two polyurethane wheels that look similar on the outside do not necessarily share identical internal structures or be suitable for the same service conditions. When delamination occurs, attributing the issue solely to “this material’s lack of durability” can easily lead to overlooking the real root causes—such as operating beyond the specified limits, sustained impact, or incompatibility with the environmental medium.

VII. How can delamination risks be minimized during procurement?

First, clearly specify the equipment’s total weight, single‑run travel distance, frequency of movement, and floor conditions. Next, indicate whether there is powered traction, frequent emergency stops, or impacts from obstacles. If the site environment includes oil contamination, cleaning agents, moisture, or temperature fluctuations, these factors should also be provided in advance. For critical equipment, conduct sample trial assemblies and observe performance on actual routes before committing to full‑scale deployment. The closer the caster selection matches real‑world operating conditions, the easier it generally is to minimize the risk of unexpected failures later on.

Written at the end

When the polyurethane tread separates from the wheel core, it may appear to be merely “a layer of glue coming off,” but in reality, it can involve multiple factors—material properties, structural design, manufacturing processes, and operating conditions. The truly effective approach is not to simply replace the wheel with an identical one whenever delamination occurs; rather, it is to identify the root cause of the repeated stress that leads to this issue.

If you’ve encountered issues like edge warping, bulging, or delamination in polyurethane wheels on your site, consider documenting the location of the problem, the duration of use, the equipment’s load, and the operating route. This information is often more helpful than a single photo of the damage in identifying the root cause. Have you faced similar problems? Feel free to share your real-world experiences in the comments.