If you have a Folger Tech i3 2020, you may notice that the rolling friction on the spool is sometimes a bit too high. This can cause the extruder wheel/gear to slip a bit and gapping may occur if the filament tension is too high. Generally the existing design from Folger works well, but if you want to push print speed to the limit, you need to ensure the very lowest friction rolling for the spool and the lowest tension for the filament going into the extruder. Here is a part which you can print two of and be done with this simple upgrade,
Requires one 623ZZ bearing for each roller. Often there are two extras that will come with the kit. Print two identical parts as you'll need two of them.
Also, this is a universal roller setup that will work with a number of different spool types/widths. No matter the width of your spool, you can quickly move the outer of the two rollers to fit.
Check out all my Folger Tech i3 2020 fixes and enhancements at http://www.thingiverse.com/pjvpjv/collections/folger-i3-2020-improvements
Supports necessary, but super easy to remove. Print as oriented.