M35A3 rims come with the run flat on the original set up. The run flat is a must when using the CTIS system as it locks the bead so the tire can be aired down for a bigger foot print. as for the break down, a tire iron, a 2x2 block of wood, and a swing hammer for breaking the bead is really all you need. i can break one down in about an hour from lug nut off to lug nut on. a 5 gal bucket is nice to have as well since the tire needs to drop all the way on to the rim so you can put the ring back on. i up them on my truck and the only thing i have had a problem with is the "O "ring not sealing. i used the old rings, and would recommend new rings if you are going to do it right. as for the 14.00x 20's. the bead is 2 inches and the bead on the 14.50x20 is 1 3/4. you can use the run flat on the 14.00, but you will have to redice the runflat width by 1/2 inches. on the up side, the 14.00x 20 tire look AWSOME on the combat rim.