There is no "open patent." A patent allows you to enforce a licensing agreement while preventing the sale of substantially similar inventions. If that licensing agreement has few restrictions, the invention might be considered "open" to use. Only when the patent expires and the invention enters public domain is it truly open.
XD is, and has always been, licensed at no cost to pretty much anyone who promises to follow the standard.
[http://www.xddriverbody.com/](http://www.xddriverbody.com/)
The problem with it from Shimano's view (besides NIH syndrome) is that (inherently, because it's a standard) there's not much engineering flexibility to modify it, and they can't use their preferred method of manufacturing cassettes. I'd hoped they'd give the one-piece thing a shot, but they doubled down on titanium.
May 25, 2018, 11:12 a.m. - Alex D
There is no "open patent." A patent allows you to enforce a licensing agreement while preventing the sale of substantially similar inventions. If that licensing agreement has few restrictions, the invention might be considered "open" to use. Only when the patent expires and the invention enters public domain is it truly open. XD is, and has always been, licensed at no cost to pretty much anyone who promises to follow the standard. [http://www.xddriverbody.com/](http://www.xddriverbody.com/) The problem with it from Shimano's view (besides NIH syndrome) is that (inherently, because it's a standard) there's not much engineering flexibility to modify it, and they can't use their preferred method of manufacturing cassettes. I'd hoped they'd give the one-piece thing a shot, but they doubled down on titanium.