A suspension assembly includes an axle pivoting plate mounted to the frame at a first pivot point and rotationally fixed to the axle. Also included is a connection arm having a first end onto which the wheel is mounted and a second end for rotationally fixing the axle to the connection arm. An actuator is pivotally connected to the frame at a second pivot point, and is pivotally connected to the axle pivoting plate at a third pivot point. The first pivot point, the second pivot point and the third pivot point are all located below the lower surface of the side rail. When the actuator is extended, the axle pivoting plate pivots about the first pivot point causing the axle and connection arm to swing rearwardly and rotate, causing the wheel to move vertically with respect to the frame to displace the trailer to a lowered position.