Hub-centric rings should be included with every new wheel purchase when vehicle fitment is specified.
They will assist in eliminating wheel balance issues by providing a nearly perfect fit between the wheel hub bore and the vehicles' outer hub diameter.
We recommend hub centering or hub-centric rings for all our products if the vehicle hub diameter does not match the wheel hub bore. We work with one of our brands, Gorilla Auto, to offer hub centering rings appropriate for a wide variety of possible vehicle and wheel combinations.
A chart of many available hub centering ring part numbers can be found at http://www.gorilla-auto.com/hub-centric-rings