Bondtech Upgrade Kit for Prusa i3 MK2 & MK2S with Dual Drive Gears





Upgrade Kits


Prusa I3 MK2/MK2S extruder upgrade IDGA

EAN13: 7350011410934 SKU: EXT-KIT-62 Categories: , , , Brand:

Prusa I3 MK2/MK2S extruder upgrade IDGA

(1 customer review)

New Version WITH IDGA Shipping Now!

with new white plastic main gear and integrated drive gear for lower run-out

This extruder upgrade is for Prusa MK2 or Prusa MK2S.
This kit is for users that also require the Bondtech Drive gears.

Save weight and print faster

This kit contains the necessary parts to convert to our newly designed extruder with 3:1 gearing ratio for better precision and resolution together with optimized geometry for the heatsink cooling and many other cool features. I also lowers the moving weight to reduce ghosting and vibrations.



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With the new Add-On this kit also supports MK3s filament sensor.
Download the files for the printable Add-On here:

Co-developed with the community

This is a co-development work with awesome guys in the Prusa Community like Chris Warkocki, Grégorie Saunier (Bear Upgrades), Olof Ogland, Erik Bjorgan, Josh Jones, Kyle Wiehe, Marc Evertz, Matt Harrison, Ocie Ward, Sando Bendig, Vecko Kojchevski (Vecko Extruder), Steven Mölby that have provided excellent feedback and suggestions of how to develop the “perfect” extruder setup for the Prusa series printer. A lot of work has been spent in this project and we have tried to listen to all the inputs in order to find a solution that can be fitted to a Prusa I3 MK2, MK2S, MK2.5 and MK3. The extruder parts are not optimized for FDM printing but for SLS printing that we use to produce the housing parts in polyamide 12 for maximum precision, strength and temperature resistance.

Light weight stepper motor included

This kit comes with this 25 mm pancake stepper that have 18 Ncm in torque for a lightweight but powerful extrusion and a new stepper cable for connecting the motor.

Original Part-cooling fan is replaced

The original part-cooling 5015 radial fan used in this setup and is not included.

This setup is made to use a 40x40x10 heat-sink cooling fan that needs to be purchased separately, it is not included. The original heatsink cooling fan on MK2 and MK2S is 30x30x10 and will not fit.

Filament sensor cover

A FDM-printed filament sensor cover is included.

For MK2, MK2S and more

This extruder will fit the stock MK2 and Mk2S carriage’s and also other popular designs like MK3, Vecko, Zaribo and Bear. Check the guide for available X-Carriage here:

Firmware change required – new E-Steps value

The E-steps needs to be updated to 415 for MK2, MK2s and MK2.5 and is easy to do by downloading this g-code file, put it on the SD card and select to print the file esteps.gcode which will set the esteps and save it. For MK3 it needs to be 830 as it uses 32 bit microstepping, use this file instead.

Huge weight reduction

Weight reduction is 121 g, from 387 g as default setup compared to 266 g for this setup (Extruder, steppermotor)

This project is licenced under GPL V3 and the STEP-files are available here.


To use the MMU2s together with the Bondtech an extra Add-On is required. This will allow sensor to trigger once the filament is reaching the drive gears.
You can download the STL file bundle here: MMU2s Add-On for Bondtech MK2/MK2s.
All credits to Leon Van Roosmalen for his amazing design. Find more information about his work and designs here:

Freight Weight 401 g
Dimensions 15.5 × 11.5 × 10.5 cm


Bondtech Github. Contains Stepfile, installation manual, exploded view, and others.

Latest Firmware

Based on 3.13.3 Firmware for MK3, MK3S, MK3S+, MK2.5 and MK2.5S

The firmware archives you will find below are based on the Prusa release mentioned above. All updates were done by Bondtech to optimize the usage of our BMG based hardware and sometimes to tweak specific features. You may find more information on the release notes below.

MMU2S & MMU3 Support

This firmware release supports Bondtech customers that are using the MMU2S or MMU3 with Prusa i3 MK25s or MK3s, and E3D or Mosquito hotends. Expand the tab that fits your 3D printer and choose the firmware file most adjusted to your configuration.

About this release

Please read Prusa’s release note to know about all changes : 3.13.3 Firmware

Source Code

Click the link below to visit the Source Code page to clone or download.

Select the Bondtech MK3 FW3133 branch

The HT firmware versions should only be used with Slice's 450C thermistors.
For Slice's 300C thermistor, choose the non HT version.

Do not use any of the files below with LGX based Upgrade Kits.
For LGX based upgrade kits look for firmware on the related Product Page.

For RAMBo 10a Mainboards

For RAMBo 13a Mainboards

For RAMBo 10a Mainboards

For RAMBo 13a Mainboards

For RAMBo 10a Mainboards

For RAMBo 13a Mainboards

For RAMBo 10a Mainboards

For RAMBo 13a Mainboards

For older versions Click here

To learn how to install a firmware update on your Prusa i3

Click here

1 review for Prusa I3 MK2/MK2S extruder upgrade IDGA

  1. Mike O’Brien (verified owner)

    I upgraded my i3 clone from a custom Bowden setup to the Prusa i3 mk2/mk2s upgrade (to get the extruder gears with the extruder). This is one of the best upgrades yet for my printer. Layers are perfectly even. Extrusion is reliable. Loading/unloading is not quite as easy as before, requiring setup in my Marlin firmware to create menu functions. I can’t say how it improved over the stock i3 extruder, since my printer isn’t an original Prusa, but this is my second Bondtech extruder and I have not been disappointed yet.

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