[rbryantaz]

I have always viewed the hub centric rings as just a way to more quickly install the wheels squarely. It is more of an install aid that isn't required if the wheel is installed carefully and properly.

One important side note that is often missed that I didn't realize for a long time:
Wheel centers being true and specific is actually more critical for tire install and balancing than putting the wheel on the car.

I realized this when I wanted to use some 7 series wheels on my e70. I considered using a router to enlarge the centers and rely on the lugs but after some research I realized there would be no way to balance the wheel if the center isn't perfect!


As for using hub centric rings in general

The center ring also prevents someone from quickly putting a wheel on with the lugs not centered and cranking them down incorrectly (by not tightening in a star pattern). If the wheel is installed carefully then there is no real advantage to them.

Where I see the rings being important is when wheels are changed quickly at the track and there isn't time to install the wheel meticulously.

IMO Rings also aren't really great for fast wheel changes either though because they can fall out, etc. I think if used for that purpose they should probably be high temp glued into the wheel.... (coat the spacer/wheel center with glue then install on the car until set) After that there is no fumbling with the ring.

For my X5 space saver on the e90 I have a plastic 74.1->72.6 ring RTVed into the wheel to make it more or less a direct fitting wheel. It isn't necessary but I had the rings laying around and it only took a minute to do. I did this before I installed the tire on the new rim and even took it to discount tire that way and they had no issues putting the tire on.

For a real racing setup where the hub gets super hot then aluminum makes sense with some higher temp glue. I have seen pictures of melted plastic rings from track days.

-Rich