A valve (10) for a dual chamber tire comprises a hollow sleeve (15) with at least two ports (21) (22) therein each of which is connected with an inflation chamber. A hollow valve stem (31) is slidably disposed within the sleeve (15). A locking means (50) is capable of holding the stem (31) and sleeve (15) in two different operating positions. An air passageway (35) connects the hollow interior (32) of the stem with the interior (16) of the sleeve (15) and is arranged so that when the stem is locked in one of said two operating positions air can be supplied to two inflation chambers (12,14) simultaneously and when the stem is in the other of said two operating positions one of the inflation chambers (12) is isolated.