I recently bought a 20" flatspin freestyle bike for my 6-year old. He loves it, but to me the handlebar stem seems to be a little loose. I have tightened the nut, but I am leery about stripping it. Someone mentioned putting a small piece of inner-tube, or black tape around the stem, then tighten.
Help please. I want to be certain the bike is as safe as it can be for him.