A frame assembly for a two-wheeled vehicle, especially for a bicycle, with - a main frame, which comprises a head tube for connecting with a front-wheel mount, and a saddle attachment means for connecting with a saddle, and - a drive-train swing arm connected in pivotable manner with the main frame, wherein the drive-train swing arm comprises a wheel suspension for a rear wheel which is to be driven and also a pedal-crank drive, associated with the drive-train swing arm, with a pedal crank for driving the rear wheel by means of the muscle power of a rider, and the drive-train swing arm is connected in pivotable manner to the main frame by means of a multi-bar linkage arrangement, wherein the multi-bar linkage arrangement is formed in such a way that the drive-train swing arm is pivotable relative to the main frame about a virtual pivot axis, and the virtual pivot axis is arranged substantially coaxially with a bottom-bracket bearing axis of the pedal crank, and the multi-bar linkage arrangement is configured as a four-bar linkage arrangement which comprises two pivot elements (42, 43), wherein each of the two pivot elements (42, 43) is connected with the main frame by in each case a first portion (42a, 43a) in a pivotable manner about in each case a first pivot axis (41a, 41c), and with the drive-train swing arm by in each case a second portion (42b, 43b), arranged spaced apart from the respective first portion (42a, 43a), in a pivotable manner about in each case a second pivot axis (41b, 41d), wherein a pivoting movement of the drive-train swing arm brings about a pivoting movement of the two pivot elements (42, 43) relative to the main frame counter to a direction of rotation of the pivoting direction of the drive-train swing arm, wherein the frame assembly furthermore comprises a spring/damper arrangement for damping a pivoting movement of the drive-train swing arm relative to the main frame, and the spring/damper arrangement is coupled with a first end to the drive-train swing arm and is supported with an opposed second end indirectly or directly on the main frame, characterised in that the first end of the spring/damper arrangement is coupled by means of a holding device which can be set in a number of defined positions (I, II) for varying a length of the spring/damper arrangement in defined manner with the drive-train swing arm, and the second end of the spring/damper arrangement is connected with one of the pivot elements and is supported thereby on the main frame. - a main frame, which comprises a head tube for connecting with a front-wheel mount, and a saddle attachment means for connecting with a saddle, and - a drive-train swing arm connected in pivotable manner with the main frame, wherein the drive-train swing arm comprises a wheel suspension for a rear wheel which is to be driven and also a pedal-crank drive, associated with the drive-train swing arm, with a pedal crank for driving the rear wheel by means of the muscle power of a rider, and the drive-train swing arm is connected in pivotable manner to the main frame by means of a multi-bar linkage arrangement, wherein the multi-bar linkage arrangement is formed in such a way that the drive-train swing arm is pivotable relative to the main frame about a virtual pivot axis, and the virtual pivot axis is arranged substantially coaxially with a bottom-bracket bearing axis of the pedal crank, and the multi-bar linkage arrangement is configured as a four-bar linkage arrangement which comprises two pivot elements (42, 43), wherein each of the two pivot elements (42, 43) is connected with the main frame by in each case a first portion (42a, 43a) in a pivotable manner about in each case a first pivot axis (41a, 41c), and with the drive-train swing arm by in each case a second portion (42b, 43b), arranged spaced apart from the respective first portion (42a, 43a), in a pivotable manner about in each case a second pivot axis (41b, 41d), wherein a pivoting movement of the drive-train swing arm brings about a pivoting movement of the two pivot elements (42, 43) relative to the main frame counter to a direction of rotation of the pivoting direction of the drive-train swing arm, wherein the frame assembly furthermore comprises a spring/damper arrangement for damping a pivoting movement of the drive-train swing arm relative to the main frame, and the spring/damper arrangement is coupled with a first end to the drive-train swing arm and is supported with an opposed second end indirectly or directly on the main frame,