Is your motor gear 3D printed as well?
I’ve done nylon herringbone and spur motor gears (wheel gears all in PETG) but had issues with the grub screws loosening due to the slight flexibility in the Nylon. I’ve always used m4 nuts inserted, flush with the flat faces of the motor shaft inside the motor gears and grub screws secured via loctite to the nylon/nut. Even then, they eventually loosen.
Have you had these issues? Do you use stronger or more rigid nylon? Edit: ah I see, nylon X… strong, rigid… Do you bond the motor gear to the shaft with glue or something? Grub screws? Keyway?
Besides the grub screws thing, especially with keyway, they held up great as long as they were sufficiently enclosed from the elements, never misaligned (herringbone), and keyway kept them turning even with loose grub screws.
I’d love to revisit the 3D printed gear drives at some point.