i was wondering what's the thickest wheel spacers that could be used with stock lug nut?

 

I think the real issue is how thick of a spacer can you install before you disturb the "hub centric" centering of the wheel. The better wheel spacers add a hub centric ring once the spacers become thick enough to be machined with an additional ring. I think that thickness is about 12mm. By that time you need to have longer bolts. Some places sell spacers with the appropriate longer lug bolts see...http://www.promini.com/product-exec/...arch_model/100

 

Another option is to go to a stud kit. If you plan on doing a lot of work to the car or changing tires for summer/winter or track tires it is definitely worth it. It will also allow you to run just about any spacer setup you want without issue.

 

I think 5mm is the thickest with the stock lugs. Most of the Mini specific spacers available thicker then that come with new lugs included.

 

My car (bought used) came with 15mm spacers and longer bolts.

 

Plus, they look cool in a Ricky Racer kind of way.