Little or minimum effort can be possible on your operator by installing VXB009100BCPU just ask your operator to push and pull, but not carry. Dia. Measured of the caster wheel in metric standard 100mm which is equal to 3.937" inch with imperial units. The wheel has a width of 50mm=1.969" inch. The caster dimensions heightwise is 124mm/4.882" inch. Mounted via a Top Plate that has a size of 138mm x 110mm x 10mm and the holes distance of 110mm x 75mm. The weehl core material is Cast iron polyurethane and has a Cast iron polyurethane tire with a low friction Precision double ball bearing. Maximum load calpacity that could not be exceeded on each wheel, remember to add safety factor, when calculating the load capacity 772 lb with a Swivel type. Ambient temperature range is -40 to 180 F. FYI, you will need to buy the VXB009100BCPU in order to get one :).