Most rockers have a back post that is straight, but set into the runners at an angle. This puts structural stresses on the chair and there is a limit to how much angle you can get in cheap timberland boots this manner. A much more expensive construction technique which improves on this is a "cut angle" back, which allows the chair to be squared up as far as the seat, and the back post is then cut at an angle to allow a larger back angle than is possible with a straight back post.
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-52247256/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-60125369/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-34685916/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-41244143/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-59574526/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-28969974/
http://chenfeiaaa.sayfasi.net/2014/11/04/httpwww-himacsuk-co-uktimberland-aspx-91500490/