When choosing wheelchair tires, safety always comes first. While polyurethane (PU) solid tires have gained widespread attention due to their unique advantages, their significant shortcomings in key safety performance cannot be ignored.
Before delving into its safety hazards, let us first have a comprehensive understanding of the characteristics of PU tires:
Advantages and Disadvantages of Polyurethane (PU) Tires
advantage:
No inflation required, puncture-proof: Solid design, no risk of blowout or air leakage.
Low maintenance: No need to check tire pressure, eliminating the daily hassle of daily maintenance.
High load-bearing capacity and wear resistance: The material is strong and resistant to initial wear.
shortcoming:
Not anti-slip (focus of this article): The material is hard and the surface is slippery, with poor grip on wet roads, posing a serious safety hazard.
Not resistant to hydrolysis: It will slowly decompose in a humid environment, causing the tire to become soft and sticky.
Aging and brittleness: After long-term use, it will become hard and crack, affecting comfort and safety.
Today, we first focus on a fatal flaw that directly affects the daily safety of users: it is not anti-slip.
Hypothetical event: A terrifying moment on slippery ground
Imagine a common scenario: On a rainy day, a wheelchair user enters a public lobby with smooth tiles, such as a hospital or a shopping mall. The floor, inevitably wet and slippery from the constant flow of people, has accumulated some water stains. As the user enters the lobby from the anti-slip mat at the entrance and attempts to turn, an accident could occur.
As soon as he applies force with his hands to push the handlebars, the rear wheels can suddenly lose grip and skid sideways. The entire wheelchair can swing uncontrollably, potentially hitting pedestrians. The user can also be shaken violently by the sudden sideways slide, potentially causing them to fall out of the wheelchair. This sudden loss of control is enough to make anyone break out in a cold sweat. This is the most typical danger of PU tires on slippery roads.
Why do PU tires lack grip?
Behind this dangerous scenario are the inherent characteristics of PU materials:
High material hardness: PU is a relatively hard material. Excessive hardness prevents the tire from deforming enough to conform to the ground like softer materials do when it contacts the ground. This results in a smaller effective contact area and lower friction.
Lack of surface design: Most PU tires have smooth surfaces and lack effective drainage and friction-enhancing patterns. When encountering a film of water, the tires are like "floating" on water and are very prone to slipping.
How to avoid this "scarce moment"? TPE tires are a better choice
So how can we avoid this potential danger from the root? The answer lies in choosing a tire with completely different material properties.
Let's return to that hypothetical scenario. If the wheelchair user had been equipped with TPE (thermoplastic elastomer) tires, their turn into the slippery tiled hallway would have been safe and smooth. This is because TPE materials can be formulated to have rubber-like softness and a high coefficient of friction.
This means that when the user applies force with both hands, the soft TPE tire deforms sufficiently due to the pressure to firmly "grip" the ground, rather than "drifting" on the water film like a hard PU tire. The inherent high friction of the material provides a firm and reliable grip, allowing the wheelchair to precisely steer according to the user's intentions. What used to be a "frightening moment" becomes a safe and smooth ordinary operation. This fundamentally eliminates the risk of sideslip and provides true safety for the user.
Conclusion: The inadequate anti-slip performance of PU tires is a significant safety flaw. In the next article, we will explore a more subtle, but equally fatal, problem: hydrolysis resistance.