The purpose of this SAE Recommended Practice is to provide a selection of disc wheels for industrial and agricultural application with a maximum of interchangeability.
This is accomplished by establishing five groups of disc wheels, in each of which the hub mounting elements are common. These groups are designated 4 bolt, 5 in bolt circle; 5 bolt, 4.5 in bolt circle; 5 bolt, 5.5 in bolt circle; 6 bolt, 6 in bolt circle; and 8 bolt, 8 in bolt circle.
Further, this document establishes an SAE part number and the maximum rated radial load for each standard wheel. In addition, the document requires the wheel manufacturer's name or trademark to be impression stamped on the wheel with location at the discretion of the manufacturer.