Large Office Chair Wheels Casters for Hardwood - Laminate Floor Mats Safe (Set of 5) Gray & Green Casters for hardwood floors, office chair wheels safe for all floors, hardwood, laminate and more. Standard casters, office chair caster come with standard 7/16" (11mm) stem and polyurethane wheels. Heavy duty wheels, set of 5 supports 550 lbs making it the best strong replacement. 6 years warranty and eliminates the need of office floor mats. Easy to install with no tools. Large diameter wheels lubricated with Lithium grease for smooth movement with a layer of rubber PU.