A device (10) is disclosed for providing air to a tire which is mounted on a wheel rim which itself is free to rotate about a fixed, that is, non-rotatable axle 22. The device includes a pump (50, 52, 54, 62) which in use rotates with the tire and which is configured to provide, when activated, air under pressure to the tire. There is a pump drive system for activating the pump. The pump drive system comprising a piston rod (56) which is connected to and rotates with the tire and a body (40) which rotates in unison with the rod (56) while the pump is inactive. An electric motor (68) rotates the body (40) with respect to the rod (56) to activate the pump and provide air to the tire. Rotation of the body (40) is superimposed on rotation of the pump with the tire. The device also includes a stator component (26) and coils (30) and magnets (32) for generating, by electrical induction, power for driving the motor using the relative rotation between the second part and the stator component (26).