which filament is better for bowden extruder

i am currently using a extruder with 3mm filament. I wanted to shift to a bowden setup to convert to dual extrusion,,, I was wondering which filament is better for bowden extruder, i have seen most of the people using 1.75mm for this setup.. is 3mm not good for a bowden extruder?

This is a common question with people on both sides. They both have advantages and disadvantages.

I am a 3mm Bowden supporter myself.

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i think the advantage of 1.75mm is its more flexible, but 3mm is stiffer and easier to apply more force to. so basically the 3mm has less "backlash" in mm, but since the 1.75mm is lower volume, they pretty much even out. it also depends on how much play you have in the bowden tube, and therefore how much extra pressure you need to get the extruder to put out.

The only thing I think I've learned is that if you use 1.75, you will also need a direct drive extruder. The reduced gear extruders cannot retract fast enough for 1.75.

I have heard of similar situations. During retraction the filament flexes in the tube and pushes against the sides of the tube causing the filament to stick in spots. I personally use 3mm due to less backlash and less retraction issues.

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My machine will have the extruder motors supported above the center of the print area just high enough to limit the angle of bend of the tubes while not extending their length unnecessarily. I am running 1.75, direct drive.