Luke,
For Carlsson rims, where would I find the width and offset information? Is it on the inside of the rim? I have some old Carlsson 1/6 rims that came with my car that I intend on selling, but I need determine the size since I don't have the original receipt. If I need to measure the width with a ruler, do I measure from outside edge to outside edge or inside to inside? Thanks.

 

it will be stamped on the back of the wheel ... it will say something like

8.5jj x 18h2 ET35

which means 18x8.5 with a 35mm offset