Aftermarket Rims & Hub Centric Rings

[Al J]

I have a set of 18" Konig Beyonds mounted with Bridgestone Blizzaks that I run in the winter. Unlike the stock Ford 19s I use the rest of the year, they require a plastic centering shim (72-7050) to take up the slight (2.12mm) gap around the center hole. The Konig center hole is ever so slightly bigger than the Fords. Never even thought about this "back in the day."
The tire guy said they aren't essential, but using them eliminates any possibility of vibration. And he said if a customer comes in & is missing one, they always leave out the right rear tire shim. Is this something new---it's sure new to me. Should I continue to use 'em or just forget about it?

 

[Al J]

No one interested or no one knows???

 

[Az Pete]

Those rings work in conjunction with the type of lug nuts you have. If the lug nuts have a tapered base that contacts the wheel, this will/should center the wheel. If the wheel uses the lugs with a shank that goes into the wheel, you need the ring to center the wheel. Any good shop should be able to tell you this.

As for the right rear wheel thing, any time there is a possible vibration issue, the right rear is farthest from the driver and will not be as noticeable when driving.

 

[Al J]

The Mustang does indeed have tapered lug nuts, as does the seats in the rim.
I see the logic of your explanation---still, they used these centering shims when they mounted the tires---I guess they aren't really necessary