Hub locator rings

[Grrrrrrr!]

http://www.speedywheels.com.au/wheel-tech.htm

Hub Location

The hub hole is the hole in the centre of the wheel which mates with the centre hub of the car.
The centre bore must locate on the centre hub as the car’s load must be directed through this point.
Locating wheels on the studs/nuts is not the correct way to locate a wheel onto a car. The studs/nuts merely prevent the rim from spinning around the hub axis, and holds the rim to the vehicle.
By not locating a wheel on the cars’ centre bore, the vehicle can sometimes encounter vibration problems, which can lead to either loosening of the studs/nuts, broken studs/nuts, or at worst, rim failure.

http://www.tundrasolutions.com/forums/t ... ction-faq/

Centering

The other element that affects directly whether a wheel can be bolted onto a car is hubcentricity. Long ago, in the deep mists of time, wheels were located by the taper of the lug nuts or bolts. This could lead to all sorts of problems, but they can be summarized by saying centering was liable to be less than perfect, and the shear stress on wheel bolts or studs could be enormous. I am not aware of any passenger car wheels now made that are not hubcentric. Hubcentric wheels have a hole at their center that fits closely over a round feature on the hub, serving to center the wheel on the axis of the spindle, as well as bear the vertical weight of the vehicle. The wheel bolts or studs then serve simply to hold the wheel onto the hub, and are loaded only in tension, where they are strong. If the studs were required to absorb vertical forces, they would be loaded in single shear, the weakest arrangement for any fastener. Factory wheels are all machined to fit their specific application exactly, and some of the better aftermarket wheels are, too. However, many aftermarket wheels rely on centering rings. This means that, instead of machining wheels specifically for each O.E. centering hole diameter, the wheel manufacturer machines all wheels to one size, and then uses inserts to give a centering surface of the diameter required for each application. This is obviously easier to do, and makes inventorying a complete wheel line much simpler and less costly. If you buy wheels that use centering rings, be sure the rings fit snugly in the wheels. If they are loose enough to fall out, how accurately can they be locating your wheel? Some tire shops automatically remove centering rings to balance a wheel, just to make sure there is no slop to make their balancing inaccurate.

Glass filled polycarb has about 1/3 the compressive yield strength of steel.. when you consider the large area the load is spread across its strong enough.

The fact cars make irt thru compliance testing without locating rings says is more about crap inspections then it being a safe condition IMO.

[neo]

and every now and then someone comes back with a piece of spectacular googling, good job GRRRRRRRRRRRRR