In order to use offset calculators, you will first need to know the offset of your current wheels. You plug those numbers (width and offset) in and then plug in the numbers of the wheels you want to purchase to compare the difference. If you're doing a static drop of 4" or less, you can get away with a +35mm offset on an 8.5" wide wheel. If you want them to tuck and not rub the fender lip, you will need to run at least a +40mm on an 8.5" wheel. Anything wider and you will need to go to a higher offset and may experience inner wheel well clearance issues. Also note that most 22" wheels come in a minimum width of 9".