Lil Wayne went on tour before he dropped new music for the Carter IV.
The I Am Music II was from March 18, 2011 to September 11, 2011 and he dropped the Carter IV on August 29th. It ended up selling almost a million copies its first week in the U.S. Tours are a great way to promote the single and album without releasing it. She can always do a second leg.
Now I think the first European leg will be without the album, but the album will be out by the US leg. She already confirmed another European leg as well.