I only use the trailer on my Roberts Roughstuff (steel frame, of course, very tough) and the hubs are XTR so it should all be plenty tough enough. Hitch and frame clean. I am sure it's a problem with me not being able to get the qr tight enough to handle the extra load- it's a much heavier load on the back wheel than my usual camping load as its largely composed of huge packs of leaflets, a gazebo, table and various other bits and pieces, tools etc. Its within the limit though and the guys at Roberts say the bike should be fine with it and agree it may be the skewer.
Should I replace the skewer maybe? Are there exceptionally tough ones out there? (I thought XTR's were quite tough?)