Yes I know the are heavy and add little stiffness to a frame. I would like to use them as a mid rack with a stash tube. This will allow me to move heavy tools and things that tend to poke a hole in the paniers to the middle of the frame with a low center of gravity. An old Reynolds catalog states these are 13 mm diameter with .9 wall thickness. I think they could be made a bit thinner with a 1/2 inch thickness. Since they are there the derailleur cables could be run down them eliminating a foot and reducing the cable radius with an adjustable cable stop on the head tube.