Variation in Bit Construction

Variations of Curb Bit Construction
The placement of the mouthpiece relative to its angle with the shanks will also affect how the mouthpiece lies in the horse's mouth. As viewed from the side, this angle is created by the position of the port relative to the position of the upper shanks. Mouthpiece placement usually varies from the port and upper shanks being aligned with one another to the port positioned forward of the upper shanks by about 20 to 30 degrees. Altering the placement, weight, and shape of the shanks and mouthpiece affects the pressure exerted on the tongue and bars and the balance of curb bits.

Bits constructed to significantly release pressure when rein pressure is released are termed over-balanced. Bits that maintain pressure without rein pressure are termed balanced or under-balanced. Balance can be determined by laying an unattached bit on your fingers, which are positioned under each end of the mouthpiece. A bit is over-balanced if the lower shanks of the bit hang forward of the mouthpiece and upper shanks. It is under-balanced if the lower shanks hang behind the mouthpiece. Most bits are designed to be over-balanced because they release pressure when not cueing. Balanced bits are used infrequently and, then, only on experienced horses and by experienced riders.