Also I think this mainly works for larger tire sizes with lower psi, and you do have to work your way around the outer tube's valve with the innermost tube. It'll still inflate fine though, nothing sharp in there. Just set it so they're side by side at the valve areas, you can't have the innermost tube pump up and push the other tube's valve up, and then push into the metal of the valve.
Last edited by stomppow; 12-30-08 at 02:30 PM.