I found an online beam design calculator that allows me to put various beam dimensions in and calculate the beam deflection when weight is hung from the end. I was surprised at how strong the frame is of this Citation trailer. Hanging 500 lbs off one frame rail cantilevered 13 feet beyond its support (the rear spring hanger) would only cause .11" of vertical deflection. In contrast a 2" x 15" x 1/4" rectangular tube would deflect about 15% more. I think I'm going to mount a motorcycle lift on this trailer. If I notice any negative handling or bowing of the frame as a result I will add a third axle.