I need to weld on some rollers to my trailers to keep them from scraping. What I've found so far are not very wide. They are more or less fixed casters. I've seen some wide rollers on trailers in the wild. Wider seems better to me, as wide a 6" or more. So I dont add to the departure angle problem by putting the rollers directly under the trailer rails, it looks like I will need to weld a cross-member between the trailer rails at a height so that the rollers hang down just below the rails. Can anyone point me to a source or offer other recomendations?