Ptfe tube? Which diameter

Hevilp

If I want to change the filament tube, which is to buy? 

Samuel Pinches

Any tube with 4 mm outside diameter and 1.75mm inner diameter is fine

Thrall2004

does anybody know the exact thread of the quick connector (coupler) for the PTFE tube? on the page it is written M8, but it is not! /// found it --> It is a M8x1!

Hevilp

Yep, it is in the wiki

TefCap

depending upon who manufactures the PTFE Tubing you have to be careful about what dimensions they are adding the +/- tolerances to. Most manufactures will tell you they are producing a 2 mm x 4 mm product and they are but the tolerances are on being placed on the ID and Wall not the ID and OD. A 2X4MM-PTFE product will have a 2 mm ID +/- .10 mm and a wall of 1.00 +/-.15 which if running on the low end could put you well shy of the true 4mm OD that you are looking for. PTFE Tubing can be produced with an ID and an OD tolerance but may require a special run.

Prokktor

Most people seem to recommend Capricorn XS tubing:
(ok those most people are mostly youtubers  who may or may not get money for recommending anything...)
https://www.captubes.com/index.html#products

I bought it myself and it did improve my print quality.

Der_Muck

I also have that Capricorn XS tube and its working fine. The most important is that the filament is not deformed because of an overhearing extruder motor. Otherwise its causing stuck filament. So its an improve but not a must have.