My 88 BroncoII has 15x7 deep dish aftermarket steel wheels so I decided after advice from another thread I should make some smooth wheel covers. I really like the looks of the mud guard style posted earlier but I had enough free aluminum for two 3/16" thick16" discs. First I made a cardboard template and cut the aluminum a 20 tpi metal blade in my jigsaw and used the bench grinder to touch them up. Like most steel wheels there is a groove about an inch in from the bead that looked like a good place to latch the cover. For each wheel I used three 1/4" threaded coupler nuts with a four inch piece of round stock welded across the top that pops into the wheel groove. I bent the round stock just enough so have to loosen the 1/4" stainless allen head bolts that go through the holes in the covers and screw into the couplers. Once the covers are in place I tighten the bolts and that seems to make the covers pretty snug. I had to cut out for wheel weights. Not saying this is the best way to mount the covers but it is working so far. I may go with four or six holders next time instead of three but I have to think about missing the valve stems. The couplers and nuts cost about $6 per wheel and the aluminum cost about $9 per wheel.
Saw them yesterday, they seem to be coated steel, which from what we have seen wont last long. Suggestion is to paint them. Or if you want to spend more about $8 ea they also have the Oneida ones coated in teflon that shouldnt rust.