A bear upgrade review  

New Member

As I had a bit of trouble with finding any good information regarding the upgrade(FULL BEAR) and what kind of difference it makes
(I have a few small modifications from stock already like new y-axis belt mounts with stiffeners added on the sides of the belt, and a x-axis screw clamped linear ball bearings), in retrospect I'd have printed the Zaribo X-axis as it should fit the the stock extruder or bondtech(as far as I can tell by reading on their page).

The conversion was fairly easy with the exception of getting the Z Axis square which a bit tricky.
(I aligned mine on a milling machine table with a mitutoyo 0.001mm digital gague aiming for less deviation under 0.005mm over the whole length).

Note that the the Prusa I3 Mk3S is already a excellent printer if carefully built by following the instructions and setup tips & help videos on youtube.

The major differences i note after getting it togther is that belt tension ended up being a bit less critical because of the rigidity of the frame, and also that a majority of the resonances that you get when printing with the stock frame is completely gone.

A quick summary:

Print quality(Equal or slightly better)  - Minimal ghosting or ringing in corners(this is at 165% feed override).
Print Speed(Much better)  - Currently I am printing parts at 164-200% feed override only change from my default settings is that I am running the hotend a bit hotter then usual and as far as i can tell theres no visible difference between how the same parts ended up before the upgrade.(I have not tweaked any settings at all since the upgrade other then the usual calibration routines with the addition of temp calibration).

Posted : 09/04/2020 9:02 am
New Member

(some parts printed after the upgrade)

Posted : 09/04/2020 6:17 pm
New Member

Hi anders-1,


maybe you should have asked Grégoire on twitter first 😉 .

There is a summary on github which should be the advantages:

  • Rigitidy
  • V-Slot system and thus more customizable
  • Option to upgrade Z axis


Best regards,


Posted : 10/04/2020 8:06 pm

Please Login or Register