They make it look MUCH easier than it is!

[aermotor]

Lay the back of the wheel on a carpet, put the a garbage can liner over the wheel, put a little air in the tube, extend the valve stem about 6 " with a wire, chain, bolt or whatever, add enough air to round out the tube. Baby powder the garbage can liner, pull the stem through and push it on by hand one side at a time - no tools needed. Pull out the garbage bag liner (hardest part). There is a Utube video somewhere showing this 10 minute job- scratch free.