Tissueward movement of the free-end saddle of a removable partial denture during function takes place around the most distal fulcrum created by the most mesial rests. Displacement because of sticky foods takes place around the fulcrum created by the most distal rests. These and other factors affecting displacement of the free-end saddle removable partial dentures are discussed, and designs intended to increase retention are presented. The forces applied to the most anterior and posterior axes of rotation can be calculated mathematically to reveal the hazards of a too-short lever arm in combination with a strong retentive clasp system.