Loose wheel with PP hub and PUR-foam tread

Loose wheel in PUR foam with PP hub, 85° Shore A

This is a loose wheel with a running surface in foamed polyurethane and a hub in polypropylene, with a tread hardness of 85 degrees Shore A. PUR foam is an airless, cellular polyurethane that gives a soft and springy run without needing air pressure. The wheel is meant for lighter rolling equipment where you want comfort and a damped run but no maintenance around an air filled tire.

The softness of the tread is the most important property of the wheel. The foamed structure lays itself against the surface and takes up unevenness, which damps both shocks and noise as the wheel rolls. At 85 Shore A the tread is clearly softer than a cast solid PU, and the rolling resistance is therefore higher; the wheel needs a little more force to get going, but in exchange gives a soft run that spares both the goods and the surface. The airless design cannot puncture and never needs pumping.

A comparison makes the difference clear. A hard PU or plastic wheel rolls more frugally and carries more, but passes every joint on as a jerk. An air filled tire is even softer and springs more on really coarse ground, but needs air pressure and can puncture. PUR foam lies between: a soft, maintenance free run for sensitive goods and lighter loads, with no air to keep track of.

The hub in polypropylene is light and corrosion free. It keeps the dead weight of the wheel down and is indifferent to moisture and cleaning agents, which suits the light load this wheel is made for. Inside the hub sit double ball bearings that give an even run and spread the load over two rows of balls, so the wheel rolls smoothly even when it moves often.

The wheels come in diameters from 315 to 400 mm and handle load capacities up to 35 kg per wheel. The large diameter is typical for this kind of wheel; it rolls easily over thresholds, cables and uneven ground and strengthens the soft run further. Since the wheel has no bracket it is mounted straight onto its own axle through the hub, which makes it easy to build into a design of your own.

Where does it fit? A loose wheel in PUR foam often sits on lighter rolling equipment, transport trolleys for sensitive goods, mobile scaffolds and equipment where you want a soft, quiet and maintenance free run. The large diameter and the damping tread make it a good choice where the surface is not entirely smooth but the load is still limited, for example indoors in warehouses, workshops or service areas.

Think about the operating environment. Polyurethane is happiest at normal indoor temperature and in dry to slightly damp environments. The low load capacity makes the wheel unsuitable for heavy loads; there a solid wheel with a metal hub fits better. The soft tread gives a somewhat higher rolling resistance, which is the price for the comfort. If the wheel stands still for a long time under load the tread can give way temporarily and take back its shape after a while.

Are you unsure whether PUR foam suits your equipment, or which diameter gives the best run on your surface? Get in touch and we will go through the load and the environment together.