A selectively switchable dual rate vehicle suspension system comprising a pushrod actuated inboard spring configuration, conventionally oriented between the unsprung mass and the sprung mass of one corner of the vehicle, comprising a torsion bar spring of a first predetermined rate, K1, and a coil spring of a second predetermined rate, K2, arranged in series so as to provide a total combined spring rate KT. A lockout actuator is arranged in parallel with the coil spring and configured so that in a first mode it allows the coil spring to move freely and in a second mode prevents motion of the coil spring such that when the lockout actuator is in a first, unlocked, mode the overall vehicle suspension spring rate is defined by the series equation 1/KT=1/K1+1/K2, and when the lockout actuator is in a second, locked, mode the overall vehicle suspension spring rate is substantially higher as defined by KT=K1, thus selectively providing both a low rate, optimal ride comfort setting and a high rate, optimal handling setting.

A selectively switchable dual rate vehicle suspension system comprising a pushrod actuated inboard spring configuration, conventionally oriented between the unsprung mass and the sprung mass of one corner of the vehicle, comprising a torsion bar spring of a first predetermined rate, K1, and a coil spring of a second predetermined rate, K2, arranged in series so as to provide a total combined spring rate KT. A lockout actuator is arranged in parallel with the coil spring and configured so that in a first mode it allows the coil spring to move freely and in a second mode prevents motion of the coil spring such that when the lockout actuator is in a first, unlocked, mode the overall vehicle suspension spring rate is defined by the series equation 1/KT=1/K1+1/K2, and when the lockout actuator is in a second, locked, mode the overall vehicle suspension spring rate is substantially higher as defined by KT=K1, thus selectively providing both a low rate, optimal ride comfort setting and a high rate, optimal handling setting.

The twist axle assembly includes a twist beam which is made of a single integral piece and extends along a length between opposite ends. The twist beam has a middle portion which extends in a first direction and a pair of end portions which extend at least partially in a second direction that is generally transverse to the first direction to reduce twisting stresses within the end portions during operation of the twist axle assembly.

An embodiment rear side member of a vehicle includes a front portion extending forward in a vehicle length direction, a rear portion extending rearward in the vehicle length direction and disposed offset to an inside of the vehicle with respect to the front portion, and a transition portion in a curved shape connecting a rear end of the front portion and a front end of the rear portion and passing through both a first point configured to engage with a first arm of a first type suspension and a second point configured to engage with a second arm of a second type suspension different from the first type suspension.

An embodiment rear side member of a vehicle includes a front portion extending forward in a vehicle length direction, a rear portion extending rearward in the vehicle length direction and disposed offset to an inside of the vehicle with respect to the front portion, and a transition portion in a curved shape connecting a rear end of the front portion and a front end of the rear portion and passing through both a first point configured to engage with a first arm of a first type suspension and a second point configured to engage with a second arm of a second type suspension different from the first type suspension.

The vehicle behavior control device includes a controller and an actuator that applies a control force to wheels of the vehicle through position control by the controller. The actuator is configured to apply a control force to the wheel by deforming the transmission member. The controller is configured to calculate a required control force for the actuator, adjust the required control force in consideration of the assumed reaction force, and perform position control of the actuator based on the adjusted required control force. Here, the assumed reaction force is a reaction force generated in the transmission member due to at least one of acceleration/deceleration and steering of the vehicle when the position control of the actuator is zero.