Height adjustment system for a vehicle

The apparatus includes a first suspension coil spring (1U) adapted to be connected to a vehicle body, a second suspension coil spring (1L) adapted to be connected to a wheel assembly, the second suspension coil spring being different in diameter from the first suspension coil spring and arranged in serial relation to the first suspension coil spring in an axial direction thereof, and an actuator (2) substantially disposed within an inside space defined by the first and second suspension coil springs. The actuator is operative to axially move one of the first and second suspension coil springs relative to the other thereof.