I have decided to retire my existing router and upgrade to what I hope to be a better performing machine and more reliable. I will use my existing machine where I can to make the necessary parts once I can make up my mind what materials to use. The solid wheel with bearings I have no idea what sort of load they can handle looks like an easy solution to travel but I need some information about loading and wear. The material I am reading about and seeing in some of the units for lack of a better description "plastic" not sure about the strength of that material either. I am convinced most of my problem is not as much bearings as it is weight on the bearings. I am needing to greatly reduce the gantry weight but maintain rigidity. I need a 4" Z axis height and all this might mean aluminum parts rather than plastic unless I can get a feel for the strength of the plastic material. any advice or information will be greatly appreciated as I have the design in mind now it's materials to get the job done.