There are two types of wheel centralisation design used in the automobile industry....
Some vehicle manufacturers use 'LUG centric' setups whereby a heavy duty lug stud & nut or bolt is used to both centralise the wheel on the hub, secure the wheel to the vehicle AND take the weight of the vehicle. All of these lug-centric fitments from the factory tend to be high grades and larger diameters than our M12's for example. Example, Ladrovers are M14x1.5 bolt diameter and theyre high tensile 12.9's.
Most cars use whats called a 'HUB CENTRIC' design. This is where the manufacturer purposely puts a steel extrusion from the hub that is ever so slightly undersize compared to the recess manufactured into the rear of the wheel. This is to both centralise the wheel and take the weight of the vehicle since the M12 studs WILL distort without this. Aftermarket nylon spigot rings stop the wheel from moving around on the hub mating face/brake disc face. Since our vehicles are hub-centric in design, this gap must be taken care of to keep the wheel centralised under any conditions.
Speak to any international wheel manufacturer and they'll tell you how important these are, for example compomotive in the UK who've supplied race and rally wheels for years. If you told them that matching centre-bore to hub extrusions are not required on hub centric vehicles they would probably stop listening to you at that point.
If you dont have spigot rings even if you do fit the wheel perfectly, hard acceleration/braking or hitting a pot hole for a few examples WILL shift that wheel slightly and distort the fasteners. The eventual result is whats known in engineering as 'impact shear' since most most fasteners arnt designed to locate the wheel too unless its a lug-centric design.
