Norwegian Name 

I am a bit surprised by the Norwegian name for Týr being given as Ty. Since Týr is hardly a common subject of everyday conversation, I accept the possibility that this may have changed without me noticing, but I am Norwegian and I have never heard the version Ty. In books, in conversations and in primary school classes on Norse mythology I have only ever come across Tyr. On Norwegian Wikipedia the article on the god himself is titled "Ty", but in the article on Norse mythology he is listed as Tyr, which makes it all the more confusing. Can anyone enlighten me on this point? Has there simply been a spelling change I have missed, or what?