Large Office Chair Wheels Casters for Hardwood - Laminate Floor Mats Safe (Set of 5) Black 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. 9 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.