Abstract: A fluid suspension unit for motorcycles, particularly off-road motorcycles for cross-country sporting competitions and the like, usable both for the front wheel and the rear wheel of the motorcycle and comprising a pair of hydraulic shock absorbers, a pair of valves connected to each of said hydraulic shock absorbers for adjusting the working strokes thereof, and a compensation tank divided by an elastically deformable membrane into an uncompressed air chamber and a fluid chamber communicating with the closed hydraulic fluid circuit including said shock absorbers and said valves. This fluid suspension unit affords the advantage over conventional fluid suspension units having independent shock absorbers that the load is equally distributed on both sides of the supported motorcycle wheel and that the rate of elasticity of the shock absorbers can be adjusted at any time by the motorcyclist without having to dismount from the motorcycle.