Basically, if I install the wheel without the hanger, the wheel is not straight. But with the hanger installed AND the skewers clamped tight, the wheel hub/axle flange then sits (just barely) on the hanger and that straightens out the wheel. I'm going to ride it for a few more months and see how it goes. So far, the wheel has not come out of alignment during a ride nor have I checked the axle flange to see if there is unusual wear.