A method and a system are provided for adjusting a pressure of a medium to a target pressure. The method includes: providing a pneumatic structure in which the medium is at a medium pressure that is a starting pressure; providing an adsorptive material operable within a range of temperatures that is proportionate with a range of medium pressures at which the pneumatic structure is operable; and adjusting a temperature of the adsorptive material to effect an adjustment of the medium pressure to the target pressure for performing a selected function. The system performs the method and includes the absorptive material and at least one regulator for adjusting the temperature of the adsorptive material.

A stud unit (3) and a device (1) for a studded tire. The stud unit comprises a housing (5) with a chamber (7) enclosing a medium, a stud (20) arranged at least partly inserted into the chamber so that it is affected by the medium. The stud is adapted to be moved depending on a change of the pressure of the medium in the chamber between a first position for a first pressure and a second position, where the second pressure is higher than the first pressure. In the second position a part of the stud protrudes further from the chamber than in the first position, The stud unit also contains a heating element (22) adapted to heat the medium so that the pressure in the chamber is adjusted between the first pressure and the second pressure.