Y Belt Installation and Tensioning

Table of contents

Compatibility: Prusawire 2026.R1

Overview

The Y belt must be installed and tensioned properly to ensure smooth and accurate bed motion.

Important notes:

  • Extra belt length has been specified in the BOM; it is expected to have some leftover belt afterwards.
  • Match your belt lengths before assembling the printer!
  • When inserting the belt clips, there should be an equal number of teeth sticking out of the ends.
  • DO NOT cut your belts until you are 1000% certain you have done it correctly. It’s okay to leave a little extra length hanging out the back of the toolhead carriage until final assembly and validation.

Prerequisites

  • You will likely find this easiest without the MK52 Heat Bed installed!

Instructions

Belt Installation

  1. Measure out 1000mm of GT2 belt for the Y axis. Double-check your measurement, then cut this length. Set aside for now.
    • Tip: Mark some tape on your desk with 100mm increments using a tape measure or calipers.

  2. Gather all the needed parts:
    • 1x 1000mm Gates GT2 Belt

  3. Slightly loosen the M3x10 BHCS securing y_belt_tensioner to the Y Carriage. Loosen the M3x20 SHCS tensioning screw almost all the way so the y_belt_tensioner_front can be pulled apart as much as possible (while the M3x20 is still engaged with the square nut). This is the position of LEAST belt tension.

  4. Insert one end of the belt into y_belt_tensioner as shown. Ensure at least 6 teeth of the belt are in contact with the ridges on the tensioner.

  5. Insert [a]_belt_clip to secure the belt.

  6. Route the belt towards the front, around the front idler bearing stack, back into and through both halves of y_belt_tensioner towards the back of the printer.

  7. Route the belt around the Y Motor Pulley and back around towards the front of the printer as shown.

  8. Route the belt around the Y Motor Pulley and back around towards the front of the printer as shown.

  9. Insert the other end of the belt into the belt slot on the back of the y_belt_tensioner. You will need to trim the belt carefully at this point. You want to have minimal to no slack in the belt and still have at least 5-6 teeth inside and engaged with the belt tensioner. Secure with a belt clip. This may take a few tries to get perfect. Err on the side of too long, you can always remove the belt clip and trim a little more off if you find it has too much slack!.

Belt Tensioning

To properly tension the Y belts:

  1. Begin turning the M3x20 SHCS tensioning screw in the y_belt_tensioner.
    • Turn clockwise to increase tension.
    • Turn counterclockwise to decrease tension.

  1. Once slack is removed, and prior to final tension:
    • TRIPLE CHECK YOUR BELT to make sure it is riding correctly on the bearings and pulleys. If it is not, loosen and correct.
  2. If the tensioning screw bottoms out (and you do not have adequate tension in the belts)
    • Loosen the tensioning bolt, try inserting one or both ends of the y belt a few more groove notches into the y_belt_tensioner and re-installing the belt clips to secure. Tighten the tensioning screw again.
  3. Follow up with tuning your belt tension with one of the final tensioning options below. Once you are satisfied, secure the assembly by tightening the M3x10 BHCS securing the tensioner to the Y Carriage!

Final Tensioning Options: