Technical Using spacers with '35 wires/40's hubs

I don't understand all I know about this. I'm trying to put '35 wire wheels on 40's hubs. I bought the spacers which everyone says you need for this application, but I can't see what good they do. The hubs have a flat surface, like this:



And so do the spacers:



The wheels have a "bump" outboard of each lug bolt hole.



So if I don't use the spacers, those bumps bear on the flat face of the hubs. If I do use the spacers, the bumps bear on the flat face of the spacers, only 1/8" farther out. I can't see what the spacers accomplish, other than effectively making the lug bolts shorter. Can someone please explain what I'm missing here? Thanks for any insight.

 

The spacer supports the inboard side of the wheel. This might make it clearer: http://www.jalopyjournal.com/forum/threads/40-ford-wheels-on-a-model-a.750368/#post-8330045

Charlie Stephens

 

Charlie -- Thanks for that link. The first picture in your post from back then cleared it up for me. The ridge on the Model A hub (with the arrow pointing to it) showed me what these spacers accomplish.

And thank you for not saying, "This has been covered before. Do a search, Dumbass!" as some folks do. That never helps anyone.

I guess I need to go shopping for some longer lug bolts. A post after yours in that thread mentions Dorman part no. 610-234. I reckon that's what I'll be looking for. Right?

Thanks again,
Mike.