Just had a play with mine and I can drop it enough to the see rear wheel (just the edge of the tyre) however it would be better if it turned in a bit more.
The disadvantage is that if its turned down and you are backing into a narrow doorway using your mirrors you cant see the door frame.
I find it easier to just leave it up and stay well away from curbs.
I rarely park on the street where I have to reverse in anyway.