The hub on the Z is 66.1mm - the (not so) :snky: (any more lol) wheels we’ve got for it are 70.5 - what I’m looking for it something akin to a hubcentric wheel spacer that’s maybe only 2-3mm thick but has a deep center-bore adaptor “barrel” - I sketched something up in Illustrator … wish I had AutoCAD on the Mac.
Can it be made? I figure it doesn’t have to be all that thick/strong, it’s just to keep shit centered so that the wheel gets torqued down straight…
Why do you need it? Automobile wheels are stud piloted. They center on the studs. The clamping force from the elasticity of the stud holding the wheel against the face of the hub is what keeps it there. You can use a wheel with center hole bigger than the hub - I’ve done it. You just need to be careful and tighten one lug all the way down by hand and not just let it hang there. You could just let it hang there and hit it with the impact and the taper on the lugs will pull it up into place - it just might mar the wheel a little bit.
If you really want one that thing would be tough to machine, you’d have a lot of waste. It would be better to make it in two pieces and weld or braze them together rather than hog all that out.
do you need the 2-3mm spacer? If not just get hub rings.
no, I don’t need the spacing at all, I need the rings - and thought that might be a stronger way to do it?
And lugcentric vs hubcentric, I won’t get into that argument… but it usually has sucked in my experience.
It could be made either way but the rings would be MUCH less than the entire piece you have drawn.
If you make the entire piece, don’t weld it, just machine it from one piece.
yeah, figured. wouldn’t be straight enough if you did join 2 parts.
easy to machine. I know there’s someone on here with a shop that does CNC work… that’d be the best way; otherwise someone who’s good with a bridgeport. Probably cost you $50-$100/per to have done at a normal job-shop CNC shop without hookups.
http://www.ezaccessory.com/Billet_Hub_Centric_Wheel_Spacers_Mercedes_p/5112m.htm
hmm although those are for a mercedes but the same concept as what you want.
Hub rings-
http://www.1010tires.com/hubrings.asp
Once you put those on there is a very good chance they will experience some galvanitic corrosion and you will not be able to get them off…
unless you grease every surface, make the actual centering surface/interface 1/4" wide or less… and taper the rest.
I ran spacers for 2 years and even anodized H&R ones will corrode some.
The fact that your centering ring is so thin will make it very fragile and prone to braking. I would get a aluminum spacer for the larger hub and have a sleeve machined out of Delrin (nylon)
Once the lugs are tight that sleeve wont experience much loading at all, if any at all. It does not have to be metal. Many rings sold are plastic.
good call on delrin - they wheels won’t be on and off THAT often that delrin couldn’t hold up to at least a season. what I really need is just hub rings, not a spacer, AFAIK the offset on the new rims should be close to perfect, like +/- 1mm 
local machine shop, 40 years experience best around. very cheap hawk machine 716 684 6490
~Krazy K