A trailer for a tractor may include a platform having a frame with an axle frame member and swivel mountings, and a pair of wheels each being mounted to rotate and swivel. A linkage connects the platform to the tractor, with a forward mount configured to mount on the tractor and permit the linkage to pivot about a pivot axis extending substantially perpendicular to a longitudinal axis of the trailer. The linkage has a rearward mount configured to mount on the platform and permit the linkage to pivot about a roll axis extending substantially parallel to the longitudinal axis of the trailer. In embodiments, the rearward mount includes a roll joint located at a juncture of the linkage and the platform, and the juncture is located substantially in a vertical lateral plane extending between the swivel mountings of the platform.