An apparatus and method is described for offsetting a lifting or lowering weight of a tow bar attached to a trailer. The apparatus includes nitrogen accumulators coupled in series to a hydraulic cylinder. The accumulators include volumes of hydraulic fluid and a gas, such as nitrogen, which are preset to have differing nitrogen pressures to accommodate a full range of motion. After initial system pressurization, no separate power source is needed to provide hydraulic support at static conditions, oscillation of the tow bar below horizontal, and lift support from horizontal to a positive angle, allowing the user to lift and position a heavy tow bar several feet with minor user force.