Abstract: A suspension system for a wheeled vehicle including a double acting ram (13, 14, 17, 18) connecting respective wheels to the vehicle body. Each ram has an upper and a lower chamber, a conduit (8, 8a, 10, 10a) individually connecting the upper chamber of a respective ram with the lower chamber of the diagonally opposite ram. Load unit (40) is connected between conduits (8, 8a, 10, 10a) to substantially equalize pressure therebetween and consequently loadings between wheels. A sensor (364) indicates the height of each pair of diagonally opposite wheels. A control unit (68) receives signals from wheel height sensors (360, 361, 362, 363) and sensor (364) to control valves (67) which adjust the quantity of fluid in the rams and the conduits to facilitate optimum position and load equalization for each of the wheels.