Wheel assembly with a tire pressure monitoring system includes a wheel rim, a tire mounted thereon, a housing having an interior in flow communication with the tire interior such that the same pressure prevails in the tire and in the housing interior, a magnet arranged in the housing and movable in an axial direction of the tire, a Hall effect sensor arranged on a non-rotating part of the vehicle in a position in which it is in a magnetic field generated by the magnet during rotation of the tire relative to the non-rotating part, and a spring arranged to move the magnet in dependence on pressure in the housing interior. The spring is arranged outside of the magnet. The Hall effect sensor senses magnetic field density of the magnet as the magnet rotates which is convertible into an indication of the pressure in the housing and thus the tire pressure.