Terry,
The tubes have to be added. It cost me about $18 each, installed. I installed the ww fluid. I finally had the method down on the second tire. Since the tubes are industrial, not Ag, they don't have a threaded stem, so the only thing holding the stem in place is the internal air/fluid pressure. One tool that would have made this process a little easier would have been a hemostat, or some very slender locking plier that you could lock on the valve stem while you were filling and replacing the valve. I used a pair of needle nose with a hose clamp holding it in place. It worked, but I think there is a better tool. It has to be very slender, because the stem guard on the rim has very little access. After you fill the tire, be ready for the "water balloon" effect when you remove the adapter and put the valve back in the stem. Have buckets ready under the wheel. My first wheel all I had was a towel and I was holding the stem with needle nose pliers with my right hand and trying to screw the valve in with my left with fluid flying everywhere in my shop and I couldn't let go of the pliers. Fortunately for me, the shop door was closed and my wife was nowhere is sight. Otherwise I think she and the neighbors would still be laughing. That is why it is important to have both hands free when you get to that stage. One good thing is I ended up with the shop floor cleaner than it's been in years.
I mentioned in my earlier post about tire pressure. I started out with about 12lbs. pressure. When I test drove the tractor to the end of our road and back, the tire and tube spun on the rim and buried the valve stem sideways in the stem guard. That was a lot of fun to fix. After returning to the tire shop one more time I learned that this type of rim and tire require at least 30lbs to stay seated.
Now that it is done, if asked would I do it again? ..... Probably. It is a relatively inexpensive process that might add a fraction of extra ballast that I might need someday. Hopefully I will be smart enough to never put myself in a position to need it, but I like knowing it's there. Good luck.
Greg