Maintain the lowest amount of friction possible on your filament feeding system.... and this will help!
The UM2 bowden-style extruder feeds from the bottom but didn't have a filament guide aligned vertically below the extruder's opening. This caused stress and friction while feeding.
I searched around and found Wired1's design and liked it the best and decided to use it as my starting point. I used a small 3M command strip to affix the mount to the back of the Ultimaker, making for easy removal.
My filament hangs above and behind the printers, so I printed multiple copies of this pulley to route the filament.
You will also need:
1x 693 bearing
1x M3x18 (or 20) screw
1x M3x16 screw
2x M3 nuts
1x small 3M Command Strip
Fit 693 bearing into center of one Wheel piece. Sandwich the other wheel piece to complete the wheel. Fit the Wheel into the Block and align with holes. Use the 18-or-20mm M3 screw to lock the wheel in place. Do not over tighten. Complete the pulley by using the 16mm M3 screw to connect the Block to the Mount.
Tip: Use Plasti-Dip on the outer portion of the tri-sided legs of the wheel that hold the bearing in place (the portion that will touch the filament once the wheel is assembled)... this will create a grip so that wheel turns with any/all filament movement.... it really helps to see issues quickly.