Normally I don't like leaving my bike out of eye sight. But if I do . . .
First three U locks: One securing the frame to the hitch rack. One locking the front wheel to the frame. And the other locking the rear wheel to the frame.
Then three cable locks: One looping through saddle rail, locking frame to hitch rack. One locking front wheel and frame to hitch rack. And one locking rear wheel and frame to hitch rack.
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Two wheels good. Four wheels bad.