I've only seen pictures of this disk, but I have drug an old pull type disk around the fields of West Central Ohio in the 60's and 70's. I think that you will find that the "hubcap" on the inside of the gang is actually the pivot point between the gangs. They probably will touch each other. They act as a thrust bearing surface between the gangs so that the frame doesn't have to hold the side pressure. At least, that is the way our old disk worked.