Abstract: A steerable wheel assembly for an in-line skate or roller ski comprises a hollow or dish-shaped wheel (11), a wheel bearing (13), and a wheel support (14) connecting the wheel (11) to a steering pivot (16) which is substantially disposed at a distance measured radially from the rotational axis of the wheel (11) where that distance is greater than the outer radius of the wheel bearing (13) and less than the outer radius of the wheel (11). Steering of the wheel occurs as the user's weight is displaced or the chassis of the device is inclined with respect to the ground toward the desired turning direction. A chassis for an in-line skate or roller ski containing a damping and centering force mechanism which may be used to moderate the behavior of a steering mechanism or suspension mechanism comprises a structural member (21), a damper housing (17), a damper piston (19), a fluid chamber (24), and a centering force mechanism (18).