I noticed leveling my bed one day that the filament was a bit taut (had tension on it) and when I relieved that tension the head dropped against my feeler gauge tighter.
I had a few long print jobs that had layer separations, etc. I noticed that while printing that tension on the filament changes all the time and has quite a bit of drag against it at certain moments. So I decided to make hubs for us to smoothly spool our filament as it should be. Cheap solution too, the screws, washers, etc. were only about $12 at Home depot, and the spinners are $2 each at Meier for the bearings. I have a dual extruder so your single extruder mount should cost less. The STL file is the final version with a recess for a washer and the bearing flipped to the other side for better balance in both hub scenarios and less plastic usage. Spent several days chewing up the bugs. NEW edit: I massaged things for a bit to reduce plastic consumption. It works without the washer and bearing as well, although they make it very smooth. My spools spin freely now. No more occasional unknown strain on the filament.
I updated the mediafire files and added a video of me removing the support in one clean move. I pared down the thicknesses since it will only be supporting a spool of filament and put holes and slots in to further reduce polymer consumption. There it is, guys. I saw on on line that had two bearings in it I still like mine better. 🙂
More pictures here, previous versions, etc. : https://www.mediafire.com/folder/ce5yir8kcrvgd/Dual_Filament_Spool_Hub
2Spool16prongHub.stl