Perhaps I didn't mount it correctly? mine came wobbly in the mail and I thought I fixed it for the most part... Maybe this has something to do with the rattle? I have a ferret nation which is pretty sturdy and have the wheel affixed to the bottom left side... Would placing it in the back against the wall of the fn make it more stable? What's the proper way to mount it and what has everyone else done? Any tips? Thanks! Srry for all the questions!)