Abstract: A detachable luggage-supporting, ground-engaging convertible accessory unit comprises a base member and at least one slide member which is guided for sliding movement on the base member. The base member is secured to a piece of luggage. A caster roller device is mounted on one slide member to form a caster roller assembly. A runner skid is connected to another slide member to form a skid-type runner assembly. A cantilever leaf spring on the base member snappingly engages each slide member for interconnecting the base member and the respective slide member with snap-type action. An access opening is formed on each slide member to expose the spring to permit a disassembly tool to remove the slide member from the base member, to thereby effect the rapid interchange of one caster roller assembly for another, or for the skid-type runner assembly. The slide member covers the spring except at the access opening so that the members are not readily detachable during luggage transport.