The Bondtech extruder upgrade kit is suitable for the Prusa I3 MK2.5S and the MK3S and already has gears. This kit includes parts to convert the extruder to a 3:1 gear ratio, which provides greater precision, higher resolution, optimised geometry for the heatsink and many other improvements.
The E steps should be updated to 415 for the MK2.5S. For MK3 it should be 830 because it uses 32 bit microstepping. Also, the Z_MAX_POS 205 must be adjusted. The correct firmware can be found at the bottom of this page.
NOTE: This upgrade kit requires additional parts (X-Carriage Kit). You can download the STLs and 3D print them.
Installation files
MK2.5S - STL Front
MK3S - STL Front
MK2.5s / MK3S - STL Rear