EZR Struder popping filament

[redbeard]

Hi all.
I've just put an EZR Struder on my Ender 3 and have been trying to use a semi flex filament, PLA Flex from 3DFillies.
almost every print, it has failed. Popping out between the drive gear and where the ptfe butts up to it.
Upon inspection of the filament that has passed through the drive and idler gears, the filament is VERY squashed and flat.
I thought perhaps the spring is too strong, squishing the filament to a shape that no longer passes through the PTFE and easier to pop out the gap between drive gear and PTFE.
I changed the spring for a shorter one (I think perhaps it was even the original spring from the stock Ender 3 extruder) and low and behold, I had a successful 2 hour print!

Is anyone else having this issue with flexible filaments?

[geneb]

What speed were you printing at? Flexibles typically like around 10mm/sec.

g.