Abstract: An eccentric bottom bracket assembly having a body member, at least two wing members, a wedge driver with two wedge members, and at least one spring member altogether forming a tubular, cylindrical assembly to fit within the inner shell of the bottom bracket area of the bicycle frame for adjusting the chain length or tension. The assembly is preferably used for the front and rear bottom brackets of a tandem bicycle for adjusting the chain that is connected to the front and rear driving sprockets. The assembly is also alternatively used in single-rider bicycles and other bicycles with the need for adjusting chain tension. The assembly allows for the wing members and the body member to circumferentially and outwardly expand or inwardly retract by co-acting with the rotation of the wedge driver which laterally displaces the wedge members in a parallel direction relative to the longitudinal axis of the body member.

Abstract: An eccentric bottom bracket assembly having a body member, at least two wing members, a wedge driver with two wedge members, and at least one spring member altogether forming a tubular, cylindrical assembly to fit within the inner shell of the bottom bracket area of the bicycle frame for adjusting the chain length or tension. The assembly is preferably used for the front and rear bottom brackets of a tandem bicycle for adjusting the chain that is connected to the front and rear driving sprockets. The assembly is also alternatively used in single-rider bicycles and other bicycles with the need for adjusting chain tension. The assembly allows for the wing members and the body member to circumferentially and outwardly expand or inwardly retract by co-acting with the rotation of the wedge driver which laterally displaces the wedge members in a parallel direction relative to the longitudinal axis of the body member.