A sensor unit for recording the direction of rotation of a wheel is embodied to record a variable that is characteristic for a direction of flow of an air stream in a tire of the wheel. To determine a side of a vehicle on which a wheel is disposed, a variable is recorded which is characteristic for a direction of flow of an air stream in a tire of the wheel. Further a direction of movement and an acceleration of the vehicle is recorded. The side of the vehicle is determined depending on the variable, the direction of movement of the vehicle and the acceleration of the vehicle.