A method, program and system to establish tire monitoring of an auxiliary vehicle (2) from a main vehicle (1) is described. The main vehicle (1) detects tire monitor identities of tire monitors (6) of the auxiliary vehicle (2) by the main vehicle. The main vehicle (1) determines whether the auxiliary vehicle tire monitor identities are associated with an identified auxiliary vehicle. If the auxiliary vehicle tire monitor identities are associated with an identified auxiliary vehicle, tire monitoring for the auxiliary vehicle (2) is established on the basis of monitoring values stored for the identified auxiliary vehicle.