Description: The outer diameter of the spigot ring must match the center bore of the wheel and behind the wheel.The inside diameter is the size of the wheel hub of the vehicle to which the wheel is installed. Description: This device is mounted between the hub and wheel of the vehicle.Hunting fills the gap between the vehicles hub and the center bore of the wheel.Guaranteed precise fit between wheel and hub.Designed to eliminate unwanted steering wheel vibration.Precision machined to stop vibrations and ensure a perfect fit every time.How to choose Hub Rings? Hub rings are sized using two different numbers measured in millimeters.The smaller of the two measurements is the inner diameter.This must match the bore of the vehicles hub.The larger of the two measurements is the outer diameter.This must match the center bore of the wheel.