Abstract: A caster assembly mounted at either bottom corner of luggage comprises a cavity disposed in an underside of the bottom corner, the cavity including an upright front wall and a slanted rear wall, a wheel mount including a positioning slot in a rear of an upper portion and a caster, and pendulum member including a thinner upper section pivotably secured to the cavity and a thicker lower section. The pendulum member is upright and disengaged from the positioning slot when the luggage is upright. Further, towing the luggage forwardly, obliquely will cause a portion the lower section of the pendulum member to enter in the positioning slot by pivoting due to gravity so as to limit the caster to move forwardly.