I have modified a number of bicycles and right now I am working on modification of a 16 inch 6 speed yeah . I have worked on a z bike making that one better was costly and not worth it . A 16" childs bicycle and a cheap Roadmaster mountain bike as well. If you have a question ask I will answer to the best of my knowledge and If I don't have an answer, I will say so . I have gained some experience in these matters and if anyone can profit from my mistakes it will be some compensation for my having made them. James