Spigot Rings (Centre Rings) are used to ensure that an alloy wheel is correctly centred on to the hub of the vehicle. If an alloy wheel is fitted without spigot rings it will probably cause the wheel to vibrate, make it almost impossible to balance, increase uneven tyre wear and in time will work the fixings loose. So, fitting wheels without spigot rings can be very dangerous.

Unfortunately most wheel manufacturers use different size spigot rings for their particular wheels so there is no "one size fits all" available

See the below catagories for some of the wheel manufatcurers wheel bore sizes.