Moveable Tandem Axle Trailer

A trailer for towing a power vehicle with a towable frame forming an undercarriage chassis and a tandem wheel assembly positioned under the undercarriage chassis. The tandem wheel assembly having a first wheel assembly, a second wheel assembly and an extension assembly moving the second wheel assembly along a longitudinal axis of the chassis between trailing position and self-propelled position, with the first wheel assembly and the second wheel assembly are positioned to support the undercarriage chassis.