Device to deflate and/or inflate tyres of a vehicle, particulary of a tractor

The device for inflating and deflating tractor tires comprises a connector mounted in the wheel rim and a housing (14) inside the rim which contains a second air tube (11) linked to the connector and which has a transverse bore (15) across it. An inner component (21) is mounted in the housing so that it can be moved relative to it and contains a third air tube (29) which can be connected to a compressed air line (31). A control valve (9) is mounted on the second air tube. The housing and inner component form an annular chamber (25) connected to the second and third air tube and a sealing ring seals the edges of this. The edges of the ring have an inverted V profile (37 -39) with a horizontal inner section (40) at a higher level than a horizontal outer section (36).