There is a somewhat related discussion involving much more expensive iglide filament here: https://www.stevesclocks.com/forum/printed-clocks/igus-filaments
I was wondering if anybody wanted to run some tests on friction of PLA vs. PETG components for the gear train? There is some very limited discussion of this online but nobody seems to know the answer: https://www.reddit.com/r/3Dprinting/comments/e8lm57/coefficient_of_friction_of_various_printed/
Good question.
99% of my printing is PLA and I have found it to be good enough. Most of my PETG data comes from Google. The consensus seems to be that PETG deforms too easily to make a good gear.
Here is a good article https://3dsolved.com/best-3d-printing-filament-for-gears/
I have run many experiments using PLA trying to solve the elusive "sticky gear" issue. These experiments compared different tooth profiles of involute vs cycloidal and traditional profiles vs shifting the active edge past the line of centers. The end result was typically a difference of 20-30% between the various gear tooth profiles.
I suspect that PETG might also show a slight increase in friction that could be compensated for by adding a bit of extra drive weight. The additional UV resistance and high temperature stability of PETG might make it a worthwhile solution.