I have found that the larger diameter the wheel, the easier it is to mount the tires. Not being able to find a used commercial tire machine, I was forced to buy a cheap import from Northern Tool, which after several modifications, has worked quite well. I have used it over the years to mount and dismount 13, 14, 15,and 16 inch tires. The 13's were quite difficult, while the 16's were the easiest (even though they were truck tires). I have never done 17's, but I bet they could be done on the floor with a couple of tire irons.
One thing about owning a tire machine; if it gets out that you have one, you will suddenly have a bunch of new friends.