I find these good for hanging 2 bikes on, I've got em in both (concrete) Sheds
EDIT - The fold up ones are better than the fixed versions, easier to move past them when not in use
I have two of these. One high up for my MTB and one below it that holds the tow bar bike rack out of the way.
I need to find a better home for my road bike though - it still leans up against some cupboards