I mounted the pair of 16X6.50-8 tires today. Because of the wider cross-section, my method was a bit different.
The larger tire has a more compliant sidewall so after applying the Ruglyde, I pressed the tire into the half rims without the tube using my jig so they lined up. For the lower rim, I used a small block of wood to press it after I couldn't move it by hand. The top rim ended up being pounded with a rubber mallet until the tube stem hole was clear. I then pulled it off the jig, a liberal application of talcum powder inside the tire and on the tube (pulled the valve out.) Carefully put the tire and rims back on the jug and tightening down the coupler nuts until they touch the top rim. Put the valve back in and apply about 10 psi of air. Let the tube straighten itself, and then pull the valve out again. Tighten the coupler nuts making certain that the tube is not being pinched. Repeat this one or two times to help seat the tires. Once you have the rim bolts together, inflate the tire to its maximum pressure (mine are 28 psi.) Re-check the rim bolts and remove the coupler bolts. Deflate to the working pressure and mount them!
Also, here is a comparison shot of the 4.80 - 8 with 5 1/4" dual adapter and the 16X6.50-8 with the 6" dual adapter.
Edited by shallowwatersailor, July 22, 2014 - 11:30 AM.