A first vehicle power steering system includes a twistable steering torsion bar, a magnet, a Hall sensor, and a valve. The steering torsion bar has a first end fixedly connected to a vehicle steering wheel. The magnet is movable in a first and an opposite second longitudinal direction with respect to the steering torsion bar and is constrained to move in the first longitudinal direction when the steering wheel is turned to the right by a driver and is constrained to move in the second longitudinal direction when the steering wheel is turned to the left by the driver. The Hall sensor has an output and is positioned proximate the magnet. The valve is operatively connected to the output. A second vehicle power steering system includes a twistable steering torsion bar, a ring-magnet support cylinder, a ring-magnet assembly, a ball-and-ramp assembly, a spring, a Hall sensor, and a valve.