During intense action like roping or fast stops, the flank cinch, also known as the rear or back cinch, holds the back end of the saddle down on the horse’s back. A double rig is a saddle that has both a flank and front cinch.
A widespread myth is that a flank cinch will keep a saddle from shifting forward while downhill riding. It will not happen. If you want to achieve this, you will need to add a crupper to your saddle. A crupper is a component that goes around the base of the horse’s tail and links to the back of the saddle.
Leather is nearly always used for rear cinches. Both ends have buckles that connect to the flank billets. A cinch connecting strap will connect the flank and front cinches. Most will have lengthy keepers on both ends to store the billets’ loose ends, preventing a rope from becoming tangled.