Rubber on nylon wheels offer a smooth, quiet, & cushioned ride that will protect floors for an economical price. The nylon core provides equivalent load and impact capacities when compared to cast iron cores, but is rust free and can be used for applications requiring wash downs, high humidity, and outdoor environments. The down side to rubber wheels is they can leave marks on the floor similar to car tires on a road and they have lower capacities compared to other wheels. If you need a non-marking wheel or more capacity, we recommend our thermoplastic rubber wheels or polyurethane wheels.We would not recommend rubber wheels for applications that require sitting in one spot for long periods of time under heavy loads.