The flank cinch provides stability to the saddle and should be snug (not tight) against the horse.
A rule of thumb is to be able to slip two fingers between the flank and the horse at the apex of the belly. It should not be loose or hang below the horse’s belly – a loose flank cinch is a danger to horse and rider.
Always use the connecting strap between the front and rear cinches to position the flank cinch properly and prevent it from becoming a ”bucking strap”.
3" Flank cinch - Double ply - Shell tool