[Eldest_Sibling (Alan)]

If the rings are lined with felt, you can remove them and add thicker, self-adhesive felt. If you feel that that would not work, due to said smoothness of the tube, you may be able to use self-adhesive craft-foam instead, and of a suitable thickness. Craft-foam will grip, and to where you'd have to loosen the rings considerably just to rotate the tube, if needed.