Little or minimum effort can be possible on your operator by installing VXB20040ALB just ask your operator to push and pull, but not carry. Wheel dia. is 40mm or 1.575" inch in inches. The wheel has a width of 40mm=1.575" inch. The caster dimensions heightwise is 257mm/10.118" inch. Mounted via a Top Plate that has a size of 38mm x 38mm and the holes distance of 129mm x 74mm. The weehl core material is Acrylonitrile Butadiene Styrene (Plastic) and has a Acrylonitrile Butadiene Styrene (Plastic) tire with a low friction Roller bearing. Each caster wheel will carry the load of 55 lb and is Swivel and Upper Brake type. Ambient temperature range is -40 to 180 F. FYI, you will need to buy the VXB20040ALB in order to get one :).