Question about Hubcentric rims vs. centering rings for aftermarket wheels
 

I was just about to order a set of 20in rims for my max, and then I talked to my tire guy and he said to make sure to get hubcentric rims (made specifically for our car) or to get a set of centering rings with the rim to make sure the center of the tire is over the center of hub. Does this have anything to do with the offset of the rim? I think our stock rims are around around 40mm.

For all you guys that have added 20s to your car already, did this issue come up? Did you have to get rims that had an offset near 40mm or did you get centering rings from the place you bought your rims from?

Does anyone know which rim manufacturer makes rims that are hubcentric for the 09 max? This hubcentric term is new to me!

All wheels have a center hole for the axle and a bolt circle containing holes through which the mounting studs pass through. Aftermarket wheels must have the same bolt circle. The center hole, however can be larger than the car's axle mount (hub). Mounting such wheels cause the wheels to be "lug centric" since the center hole cannot be mated to the axle mounting surface. Lug centric is not desired. To correct this, an adaptor is made that fits over the axle mount (press fit) that allows the aftermarket wheel to be on the axle mount. This is "hub centric" and ensures that the wheel's rotational axis is coincident with the axis of the car's axle.

As far as I know, the adaptor is always available from the aftermarket wheel manufacturer.

So, is this adaptor that you are talking about the same thing as the centering rings? This whole concept seems very complex to me. I am not use to dealing with this much physics related to mounting some wheels. Thanks.

Yes, the adapters are the centering rings. It doesn't matter if you get wheels that fit perfect or ones that require rings. Either way you end up in the same place; with the wheels mounted in the way CT Maxima explained so nicely.