These have held up well for the first year.  I would suggest the the Polywood company either include extra rings for the wheels or offer them for sale as a separate item on their website.  Two of our 12 wheels have lost the wheel ring that fits in a groove on each wheel to protect the surface of the wheel.  I had to contact the company and go back and forth in several emails and finally they put together an order for me where I could order and pay for extras.