Update 11/15/19: There was a minor collision point in the updated Z-stepper mounts I shared two days ago. I decided to start from scratch with the latest Bear V2.1 mounts and modify them to suit the lowrider setup. The latest parts include all of the bear V2.1 modificatio, improved structural rigidity over previous veio due to the reintroduction of the angled support on both sides of the motor, and overall less reduction of material for the fan duct and pinda clearance cutouts. This veion should be good to go. I've added LCD mounting brackets that drop the LCD 9.5mm for clearance of the bed frame. These are italled and work as expected on my printer. Also, I have reduced the OAH after the modification to allow for successful XYZ calibration. The newest firmware, based on 3.8.1 and including linear advance 1.5, is available here: Update 11/13/19: I have revised the Z-stepper mounts to include all 4 mounting holes for the stepper motor, as well as most of the Bear V2.1 updates which include a tighter fitment of the mount around the stepper's sides and a recess for more perfect alignment between the mount and the motor's upper bezel. Making clearance for the pinda and fan shroud required some integral supports on the right mount. I'm running the BNBSX Short Ea extruder and everything has plenty of clearance, but YMMV with other extruder desig. Update 8/26/29: I have been running the updated firmware with 229mm maximum Z height and LA1.5 on my Mk3S full bear since 8/19. I've found that the printer is able to print normally at the new maximum Z. So far there does not appear to be any unexpected issues created by the lowrider mod. With the recent announcement of the revised bear frame which will allow all Mk2/2.5 machines to utilize the same frame as the Mk3, I hope to soon update this mod (as necessary) to work with the Mk2/2.5. I anticipate a maximum build volume of 221mm for the Mk2/2.5 with the lowrider mod. ALSO, now that I've had a chance to observe the pinda and fan duct clearances closely, I plan to update the Z-motor brackets to the standard '4-mounting-holes' design in the near future. This will eliminate the need for the Z-motor 'strap' that this mod currently uses. Update 8/19/19: I discovered that the printer wasn't using the full build volume, to the tune of about 5mm. I have updated the custom firmware (veion 2 availabe here: to a maximum build height of 229mm. You can now make models that are 9" tall with your mk3s full bear! Update 8/5/19: I have been running this system since 7/31/19 and have found no issues with it's functionality. My mk3s is printing better than ever and has no issues printing the fit layer all the way to maximum Z height. I'm currently using this printer for production of commissioned prints and the quality exceeds expectatio. Please post your make if you decide to try this system! Update 7/31/19: I'm printing a benchmark at maximum z height right now. As soon as it's done I will itall the lowrider mod on my mk3s and load up the custom firmware I just finished ( I will then print the same benchmark, maximized for the new build volume, tonight and upload pictures of the side-by-side fit thing tomorrow. Note that the custom firmware includes linear advance 1.5, so it will require recalibration of linear advance 1.0 settings. Update 7/31/19: Update: Modified Z-motor mounts have been uploaded to account for x-axis collisio created by the lower bed mount. This modification is still untested so use at your own risk. I am printing these brackets now and will be testing throughout the coming week. Update 7/30/19: NOTICE: It has been reported that using this mod will result in multiple collisio, including a collision at the far left (home) position of the x-axis and another at the far right position of the x-axis. These collisio involve the fan duct (on the left) and the pinda (on the right). I am looking into a solution that will include modification of the z-moto mounting brackets. Until said solution is available I do not recommend that anyone itall this mod. That being said, I've printed all of the mounting brackets and plan to begin testing the mod within the week. This mod is untested, so try at your own risk. All y-rod, motor and pulley mounts have been moved down by 14mm and modified to plane from the bottom of the front/rear extrusio, rather than the top. Custom firmware will be available in the future. This design will be modified (if necessary) for the mk2.5s full bear in the near future. Note I have included an adjustable y-idler pulley with a 3D printed 20T pulley that utilizes two MR63ZZ L-630 bearings, as well as an m3x12 button-head screw. The standard pulley carriage from the original design (see remixes) should work for use that dont want to build the plastic 20T pulley and use the m3 screw.