Little or minimum effort can be possible on your operator by installing VXB013125WBCPUB just ask your operator to push and pull, but not carry. Dia. Measured of the caster wheel in metric standard 125mm which is equal to 4.921" inch with imperial units. The wheel has a width of 50mm=1.969" inch. The caster dimensions heightwise is 210mm/8.268" inch. Mounted via a Top Plate that has a size of 140mm x 108mm and the holes distance of 105mm x 75mm. The Ball bearing design will enable the Polyurethane and Cast iron core tire to roll easily with a core made of Polyurethane and Cast iron core. Each caster wheel will carry the load of 617 lb and is Swivel and Upper Brake type. The caster wheel temperature range = -40 to 180 F. FYI, you will need to buy the VXB013125WBCPUB in order to get one :).