With big tires, doing them by hand is best for a small operation. If you aren't specializing in tire sales, it would not be worth the money. Get a good bead breaker, some quality bars, a remote inflator hose, and a cage. Once you get the hang of it, it is not that difficult. If you are going to buy a machine, go to your big truck tire shops and ask them which machines work good, and have been reliable. Having an off brand one that is not working, and parts/repair not available will be a huge disappointment. I have been doing my own tire mounting on my trucks for a couple years, and have saved twice what I spent on good tools. And, hand tools are portable, the machine, not so much. You will be able to get your trucks back on the road quickly, if you keep some spare tires around. You can even do service calls on RVs, and trucks if you want to. Lastly, Avoid "Split Rim" wheels unless you have been properly trained to safely handle them. In my opinion, they should only be deflated(using ALL safety measures), and replaced with solid wheels.