Am I missing a gasket between the two piece wheel system? The air leaks out. How do we make this air tight and not leak?

 

I had a tire that was leaking also. I took the rim apart and was missing the gasket so i cleaned it up real good put a bunch oof silicone gasket maker between it bolted it back together and let it sit overnight before airing the tire back up hasnt leaked since

 

It is a rubber o-ring. It is a crappy set up. Clean both sides up good and put some silicone like mentioned above might help... I just put tubes in them.