My father is selling his Coates tire changer.  

http://peterborough.kijiji.ca/c-buy-and-sell-tools-equipment-Coates-Tire-Changer...

Model 20 - 20  Coates
works very well
air powered

I've upgraded to a new machine.  While I would like to keep this one too, I need the money.
I've used this on steel and alloy rims with no problem.  It even will run off a small portable compressor, if needed.
These machines are known for their durability and quality.

Reasonable offers will be considered.