Basically, hub centric wheel spacers mean their center bores are designed to fit perfectly on the axle hubs and the wheels. In this way, the wheels are centered by the hub connection and the lugs can hold it flush against the mounting plate. This allows the wheel to support the vehicle’s weight and fill the remaining space for a more tightly fit, reducing vibration.
However, lug centric wheel spacers mean their center bores are made to fit many different vehicles. In a lug centric design, the wheel is attached and centered by the lug nuts or wheel bolts– instead of the hub. Lugs can be bent under force and provoke vibration in the car.