I don't know what you type of vehicle you are planning on mounting these tires, so I am assuming you are talking about a full size pickup or similar. Most of my statements apply regardless of what your intended use is, except the loads may be more in line with the tire's ratings.
Here's the tech info direct from the Michelin Databook.
A few things you want to consider.
1. The rim this tire was designed for is 10" wide. As maddog indicated, you can (probably) fit them on a 7.5 or 8" wheel, but it won't be pretty, and you'll lose a lot from the footprint. Mounting them on this width wheel is not recommended.
2. The beads are flat seat style. This requires a different wheel than your typical 15 degree seat on most truck wheels. Check your wheels carefully.
3. Not only will you need a tube, you will also need a flap to protect the tube from the wheel and the wheel / tire interface.
4. Recognize that the 14.00R20 is designed to carry up to 11,000 pounds per tire! and the 16.00 is up to 14,540 pounds! Your rig may not even weigh half what one tire is designed to carry. You'll be giving up even more footprint, even if you run it at ridiculously low pressures.
5. These are steel belted casing plies, so they will not flex near as well as your typical textile plies, especially under the loads you are likely to put on those tires.
Hope this helps some.
