Polyurethane on Iron wheels are a superior choice in many applications compared to a Rubber on Iron wheel. The polyurethane is more resistant to grease, oil and abrasive wear than a rubber tread wheel is. Polyurethane on Iron wheels are a popular choice for many carts rolling on factory floors and moving through manufacturing environments. Most poly on iron wheels can typically be found in a few different color variations – Red on Silver, Green on Silver or Green on Black. In many cases, the durometers on these different colored wheels are the same. The colors serve as an aesthetic benefit to the user. One potential downside to a Polyurethane on Iron wheel is that the bonding agent holding the polyurethane tread to the cast iron core can be weakened by being exposed to chemicals, shock impact, overloading, and the buildup of heat. These factors can cause the tread to fall apart and break off from the core compromising the integrity of your wheel. This will require you to replace the wheel to ensure the safety of the user. The tread hardness on a poly on iron wheel is usually a 90 to 95 Durometer Shore A which can safely operate in a temperature range of -20 to 180F. Oftentimes, the determining factor for selecting a polyurethane on iron wheel is having an increased load capacity while offering a quiet roll with quality floor protection. Polyurethane on Iron wheels are a fabulous choice for many industrial applications and can be a very long lasting solution when used in the right environments.