******Need help shaving rim backspace.....

I have looked all over with no luck...anyone knows how to professionally shave 2-4mm from backspace of the rim...thanks

machinist.

machinist or any wheel repair shop can do it

however it also depends on the wheel and how much pad it has to shave. 

But like above, any machinist or reputable wheel shop.

depends on how far before it hits the lug seat also.