An auto-balancing transportation device having a compact form. Left and right foot platform sections are coupled for fore-aft tilt angle movement relative to one another. Left and right wheels are provided under the respective foot platforms. With a rider's weight directed primarily downward onto the wheels and not onto the coupling structure, the coupling structure may have sufficient space to house the battery. In addition, more efficient and lighter weight supports and bearing arrangements may be used in the coupling structure. Various embodiments are disclosed.