A compensation chain hangs beneath the car and counterweight to offset the changing weight of the suspension ropes as the car travels. Without compensation, the rope weight on each side shifts as the car moves, unbalancing the system and increasing motor load at the extremes of travel. Chains are typically used above about 30 metres of travel, often sheathed in plastic to reduce noise. For higher speeds compensation ropes with a tensioning pulley are preferred because chains can swing.