Kingbolt, also spelled king bolt, is a metal pin used to hold two parts of a vehicle together, such as a wagon or a carriage. It is also known as a pivot bolt or a center pin. Other synonyms for the kingbolt include kingpin, main bolt, central bolt, spindle, and axis pin. The kingbolt is an essential component of the vehicle's suspension system, and it plays an important role in ensuring the vehicle's stability and safety. Since the kingbolt is subject to wear and tear over time, it may need to be replaced periodically to maintain the smooth functioning of the vehicle.