CliffN...do you have hub pilot wheels or the old style wheels that require a "barrel nut" ?
If you have the old style, the length of the wheel studs can come into play big time. I have had some serious problems on the dump trucks where they came from the factory with double steel wheels. When the alum. wheels were added, in effect, the the extra thickness of the alum. wheel actually cause the outer nut to rest on the barrel nut out past the end of the stud. I seen this actually sheer the barrel nut off at the end of the stud.
Another problem that I have ran into is with trucks that came equipped with double alum. wheels and were changed to either alum/steel or double steel. In this the wheels studs will be much longer to accomadate the extra thickness of the alum. wheels as mentioned above. When you put either one or two steel wheels on that hub, more of the stud is exposed. If you go back with the same barrel nut, it can bottom out on the end of the stud, leaving the inner wheel completely loose. The way you can check this is to tighten one barrel nut and take it back off. By looking into the inner part of the barrel nut, you will see a ring at the bottom of the threaded hole where it bottomed out on the stud. It can do this even though you it looks like it tightened up. Always check it when you make these changes!
I am sorry for making such a long reply here and if you have hub pilot wheels, these things don't apply.
Bottom line: If you have barrel nuts, be very careful when changing alum. to steel and steel to alum. My local mech./parts store actually had a chart that he let me look at that told me what length studs and barrel nuts I needed. I would suspect that there is a chart somewhere on this worldwide web that would tell you the same.
Don't be discouraged with all this...it is possible and it is possible to spend as much on barrel nuts and studs as you do on the wheels, but there's nothing like a nice set of alum. wheels
Let me know if I can confuse any further..lol.
Somehow, I doubt it..lol.
Have fun, but make it safe!