I have mounted ORNREY tires also with motorcycle tubes between the tire and rim, but if the tube gets stuck as you air it up, go ahead and air it up to seat the other side bead, then let the air back out and set the tire/wheel on three cinder blocks at three different spots like 12: oclock, 4:00 oclock and 8:00 oclock at the edge of the tread to suspend the tire and wheel above the ground so that you can push the center of the wheel down so the tire bead will meet the rim and air it up. Another way is to get two tiedowns with rachets and place them in the center of the tread all the way around the tire with them oposite each other, tighten (rachet) them tight and as you do the beads will push outward as the center is pulled smaller, then air enough to seat the bead.....5-6 lbs air, as you fill with air loosen he rachets until they are completly loose and air to spec. Another way is to use 2x4's cut to 4-5 inches wider than the wheel width and position them in the tire at equal distances apart (say three or four 2x4's) and set them outside in the sun for a while to 'relaxthe tire fron the heat to a wider bead width, once they are wider and dont colapse so much, mount them and air up, also you can use a truck tube to spread the beads before you mount them, again in the sun to warm and relax the tires thus spreading the beads apart. It's always easier with the valve core removed as the volume of air is able to inflate faster thus less bead leakage, lots of soapy solution is a big pluss also Something you have to remember with giving out these tips, is that lock rings are VERY dangerous for a novice, also that the advice you give MUST be VERY clear. Tubless tires are relativly simpler but dangerous as well and by giving out advice, you may be responcable for someone making an error with your instructions, ERRORS can be fatal to more than the person performing the work, as there can be bystanders injured as well PLEASE... know what you are doing...clearly with no question !!! Ether works, but you could look like this if your not lucky
So for aother choice, Ken-Yool has a couple items, now for the Ether method without the ether is the BLAST TANK ...... also you have a bead ring for 19.5 tubless wheels which would stretch to accomidate the 20" rim. As you see in the other picture is a bead squeeze tool, as you see the method it employs, this could be accomplished with two RACHET tiedowns as mentioned earlier placed 180 degrees apart in tandom with the BLAST TANK