My wife has a 2002 Xterra and the rear tire has a screw in it. I took off the lug nuts and there is this rusty looking metal retaining ring in the middle of the wheel. I have no idea how to get it off and I do not want to break it. Anyone know how to get it off?

kick the sidewall at the top of the tire

AFAIK there is no "retaining ring" the wheel is prob just stuck, my 4runner does this, i have to kick the tire to get ot off