Trailers

The present invention includes a trailer 10 supported on a pair of wheels 14. When loaded, or during loading the strain in one or both arms 18 is monitored. If that exceeds a predetermined value then adjustment of the load can take place either in the forward or aft direction or in a sidewards direction. Two wheels are provided at each side of the frame each pivotally connected to a common member that is in turn pivotally connected to the frame.