Despite the size of the caster (Ø100 - 200mm), R Series is rated as Light duty type - only 60 kgs per caster. Rubber tread is just light cushion but will help reduce noise and surface protection.
Shiny Nickel coating enhances rust and corrosion resistant. Steel hubs are soldered with the cast-iron core so it is hard for dust, water and silk to intrude the ball bearing and shaft. Thus lessen the needs for maintainance.