The information in this SAE Information Report is the result of studies by the Automobile Manufacturers Association, American Trucking Association, and Truck Trailer Manufacturers Association, to achieve interchangeability of equipment which will comply with the legal dimensional limitations for the majority of states and yet permit increased loading space within these dimensions. This in no way supersedes other information in the SAE Handbook on this subject. Some cases will require more care in application allowing splash shield clearance at trailer support interference points and positioning fifth wheel to allow trailer swing clearance on an 11% grade. All dimensions are given in inches. Table 1 and Figures 1 and 2 show basic requirements for interchangeability of truck tractor and semitrailer equipment. Figure 3 shows the interchangeability of the doubles converter dolly. The formulas for determining LWC, OAL and CFW are: where: FW = fifth wheel advance R = Rear axle tire radius LWC = 90 in = 64 in (short trailers specifically intended for use with two axle tractors) W = 96 in = 102 in C = Clearance, 4 in where: H = Distance from intersection at back of cab and trailer swing radius to top of fifth wheel with zero trailer clearance to first obstruction FWP = Top face of fifth wheel to centerline of pivot, 3.50 in SR = Swing radius of trailer corner The Truck and Bus Coupling & Interchangeability Committee which owned this report was inactivated and the technical expertise for the subject report within the Truck and Bus Council is not available at this time. This standard was transferred to the Total Vehicle Steering Committee to stabilize the standard following the editorial corrections in the recently approved version. In addition, this technical report covers technology, products, or processes which are mature and not likely to change in the foreseeable future.