Take my advice and get shelves with some kind of brackets below.  You will never get these to be solid.  The concept is good, but as my handymen and all of us realized, the bored holes are not always exactly the right diameter and the shelves don't sit tightly on the bars.  We had to add super contractor glue and unfortunately glue them to the drywall to get them to be sturdy.  Nice look but get ones with brackets and you'll save yourself a nightmare.