Abstract: An hydraulic floor jack of the type which rolls on the floor to engage under a vehicle to lift it. This jack is characterized by an articulated frame to operatively and selectively use less floor space, flexible tire wheels to allow the load on the jack to be transmitted directly to the floor by the base of the jack upon flexing of the flexible tires under the load until the best rests on the floor, and by a narrow construction and arrangement of the operative parts to allow engagement in narrow spaces and in particular between the tandem wheels of a truck.