Robo 3D Spool Resizer

I'm brand new to 3D printing, and this is my first attempt at modeling something and printing it, but it turned out surprisingly well so I figured I'd upload it since I couldn't find one someone else made on here.
When I first started using my Robo 3D with the spool that came with it, the spool kept falling off of where it should be on the spool holder, and created more tension for itself. In order to fix that, I made this ring to decrease the size of the hole in the center of the spool. So fa