Originally Posted by thstone

Hub Centric Rings

I initially installed the new Cragar Soft 8 wheels straight onto the X5 to see if I really needed hub centric rings.

Hub centric rings are designed to fill in the gap between the hub of the car and the center bore of the wheel. Most aftermarket wheel manufacturers design their wheels with a centerbore large enough to fit a wide variety of cars. These wheels have a larger center bore diameter than the hubs of most the vehicles they are made to fit onto.

As such, the wheels are mounted "lug centric" as the wheel lugs are the only thing keeping the wheel centered on the hub whereas stock BMW wheels will always have a very close fit between the center bore of the wheel and the diameter of the hub to more accurately center the wheel.

The concern is that a lug centric installation can result in wheel vibration because the wheel is not accurately centered on the hub.

Which is exactly what I found. With the lug centric installation, I would feel a vibration most pronounced at around 50-60mph. It felt exactly like a wheel out of balance.

Then I installed a set of hub centric rings to fill the gap between the wheel and the hub. This provided a very snug fit and centered the wheel to the hub. The result was that the vibration disappeared and the wheels/tires drove perfectly.

Hub centric rings come in sizes to meet almost every application. In the my case, I needed rings with a outer diameter of 83.82mm to fit the wheel and an inner diameter of 72.5mm to fit the X5 hub. I was able to order a set in this size from Amazon at a cost of less than $10.

The rings are constructed of a very hard plastic material. Installation is easy, they simply install over the hub and the wheel goes outside of that.

Here is a pic of the hub centric rings installed: