Sinking chair. What causes this?

The most likely cause for a sinking chair is due to a worn out gas cylinder. Even though the gas lasts a long time then time will come when a replacement is required. You can find our range of gas cylinders in our online shop. We replace gas cylinders onsite or if you are comfortable to replace it yourself, you can just order it through us. Our office chair gas is rated class 3, ensuring you received a quality product.