What function does the curb chain or strap have on a Pelham bit?

The correct function of the curb chain or strap on a Pelham bit is to prevent the bit from rotating too far. This is particularly important because a Pelham bit is a combination bit that provides both direct action and leverage. The curb chain works by creating pressure on the horse's chin when the reins are pulled, which helps to maintain control and communication with the horse while preventing the bit from flipping over too much. This added control can help the rider communicate more effectively and can assist in regulating the horse's head position.

Other options describe functions that do not accurately represent the purpose of the curb chain. While the weight of the bit can impact its function, the primary purpose of the curb chain isn't to increase weight. The idea of allowing the horse to nibble on the shanks does not align with the design of the curb chain as it serves a functional role rather than a recreational one. Lastly, the curb chain is certainly not for decoration; it is an essential component that provides vital control when riding with a Pelham bit.