A narrow aisle lift truck has hydraulic control of steering with means to prevent oversteer by reaction between the wheels and the ground. When steering left, hydraulic fluid flows via line A to the motor and exhausts from the motor through the opposite line B and via a relief valve F which is opened by the pressure in line A. When the steering angle remains constant there is no pressure in A and valve F is closed so that any forces tending to deflect the steering either way are resisted by the one-way flow valves in line A and the closed relief valve F. Bypass C, D are arranged to open under excess pressure so that in the event of for example accidental impact raising the pressure in one or other line the appropriate relief valve opens and this guards against damage to the circuit.
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