A wheeled cart includes a number of unique methods to synchronously stow all of the rear wheels of a fold flat, compact wheeled cart device without removing any of the wheels themselves and the innovations are applicable to cargo carriers, golf bag carts, trolleys, baby strollers, and other devices for moving cargo. In alternative designs, the folding motion of either the forward wheel frame, or the swiveling motion of the rear wheel frame, or both, synchronously setup or stow the cart's at least two rear wheels to achieve an ultra-thin stowed profile, orienting all the cart's wheels in a co-planar stowed relationship, closely parallel with all other parts.