Voron V2.4 Belt Tension Maintenance — Keep Your Gantry Perfectly Tuned

Maintenance V2.4 Belt Tension

The Voron V2.4 uses a complex four-belt system — two AB drive belts for X/Y motion and two Z belts for the gantry lifting mechanism. Each pair has its own tension requirements, and keeping all four in their sweet spot is essential for dimensional accuracy, ghost-free prints, and long belt life. Last updated: May 2025.

This maintenance guide covers scheduled belt tension checks, exact frequency targets for AB and Z belts on the V2.4, belt cleaning procedures, signs of belt wear, and a step-by-step replacement walkthrough. Whether you're doing routine maintenance or diagnosing a print quality issue, this is your reference for everything belt-related on the V2.4.

V2.4 Belt System Overview

The V2.4 has two independent belt systems:

AB Drive Belts (2x GT2-6mm): Connect the XY gantry motors to the toolhead via the belt path through the Z joints. These belts control X and Y movement of the toolhead. Each side (A and B) has its own belt that must be tensioned independently.
Z Belts (2x GT2-6mm): Connect the Z stepper motors to the lead screws that raise and lower the gantry. These belts must be tensioned evenly to prevent the gantry from binding or tilting during Z movement.

All four belts use GT2-6mm profile with 2mm pitch. The AB belts are longer (approximately 2.2m each depending on build size) while the Z belts are shorter (approximately 600mm each).

Recommended Tension Targets

Tension is measured by plucking each belt like a guitar string and measuring the resonant frequency with a belt tension meter app or a dedicated gauge. Here are the targets for the V2.4:

Belt	Frequency Target (Hz)	Tension (N/cm)	Span Length (mm)
AB Belt (A side)	110 ± 5 Hz	2.2 N/cm	~160 mm
AB Belt (B side)	110 ± 5 Hz	2.2 N/cm	~160 mm
Z Belt (left)	90 ± 5 Hz	1.8 N/cm	~130 mm
Z Belt (right)	90 ± 5 Hz	1.8 N/cm	~130 mm

Critical: The AB belts must be tensioned as close to identical as possible. A difference of more than 5 Hz between A and B sides will cause gantry racking — the gantry will skew, causing the toolhead to wobble as it moves across the build plate. The Z belts must also be matched to prevent the gantry from tilting as it moves up and down.

When to Check Belt Tension

Belt tension on a V2.4 drifts over time as the belts stretch and seat into the pulleys. Follow this schedule:

After initial build: Check after 10 hours of printing. New belts will stretch noticeably in the first 50 hours.
Routine maintenance: Check every 100 print hours or once per month, whichever comes first.
After a crash or collision: Immediately check all four belts. A crash can stretch a belt permanently.
When print quality degrades: If you notice new ghosting, VFAs, or dimensional errors, check belt tension before chasing software issues.

Checking AB Belt Tension

Tools Needed

Belt tension meter app (Gates Carbon Drive App, Belt Tension Meter, or similar)
Small flathead screwdriver or hex key for tensioner adjustment
Pen and paper to record readings

Procedure

Home the printer and move the toolhead to the center of the build plate (X: 125, Y: 125 on a 250mm build).
Power off the printer and disconnect the stepper motors to allow free movement.
Locate the A-side belt between the Z joint pulley and the toolhead mount. The free span is approximately 160mm on a standard 250mm build.
Pluck the belt firmly in the middle of the free span — like plucking a guitar string. Use your thumb and forefinger, pull the belt sideways about 5mm, and release.
Measure the frequency with your app. Aim for 110 Hz. If the reading is unstable, pluck 3 times and take the average.
Repeat for the B-side belt.
Adjust using the belt tensioner on the Z joint. Turn clockwise to increase tension, counterclockwise to decrease. A quarter turn changes the frequency by approximately 5-10 Hz.
Re-pluck and re-measure after each adjustment. Wait 30 seconds for the belt to settle before re-measuring.
Both sides should be within 5 Hz of each other.

Checking Z Belt Tension

Home the printer and move the gantry to Z: 150 (midway up the frame).
Power off and disconnect Z steppers.
Locate the Z belt on the left Z motor mount. The free span is approximately 130mm between the motor pulley and the lead screw pulley.
Pluck and measure. Target: 90 Hz.
Repeat on the right Z belt.
Adjust by loosening the motor mount screws and sliding the motor up or down to increase or decrease tension. Tighten the screws to lock the position.
Both Z belts must be within 3 Hz of each other to prevent gantry tilt.

Belt Cleaning and Lubrication

GT2 belts are self-lubricating and should not be oiled or greased. However, they can accumulate dust and debris over time. Clean the belts every 200-300 print hours:

Wipe each belt with a lint-free cloth dampened with isopropyl alcohol (90% or higher). Do not soak the belt.
Use a clean, dry cloth to remove any residue.
Run the printer through a full XY motion sequence (use a macro that moves the toolhead across the full build plate) to expose all sections of the belt.
Inspect the belt for cracks, frayed edges, or missing teeth. Any of these mean the belt needs replacement.

Signs of Belt Wear

Frayed edges: The edges of the belt are no longer cleanly cut. Fraying indicates the belt is rubbing against a sharp edge or pulley flange.
Cracks at belt teeth: Micro-cracks forming at the base of the teeth. This is a sign of over-tensioning or belt age.
Shiny glazed surface: The belt has a polished appearance on the back side. This indicates slipping on the idler pulley.
Worn teeth (peeling): The teeth are losing material or shape. The belt will skip under load.
Stretched belt: If you can no longer achieve proper tension at the end of the tensioner's adjustment range, the belt has permanently stretched and needs replacement.

AB Belt Replacement Procedure

Tools needed: 2.5mm hex key, 3mm hex key, belt trimming tool or sharp scissors, new GT2-6mm belt cut to the correct length for your build size.

Remove the print head (hotend, extruder, StealthBurner assembly) from the gantry to access the belt path.
Remove the Z joint covers on both sides.
Loosen the belt tensioner fully — turn it counterclockwise until the belt is completely slack.
Disconnect the belt from the toolhead carriage. On the V2.4, the belt loops around two pulleys on the carriage and is secured by a printed clamp or metal clamp plate.
Thread the old belt out of the belt path. Note the routing carefully — take a photo before removal.
Thread the new belt through the path. The AB belt path goes: motor pulley, idler pulley on Z joint, front carriage pulley, back carriage pulley, idler on opposite Z joint, tensioner pulley.
Clamp the belt to the carriage, ensuring the belt teeth face the correct direction and the belt is not twisted.
Tension the belt to 110 Hz following the procedure above.
Repeat for the other side.
Reinstall the print head and Z joint covers. Check all belts are properly seated on pulleys before powered movement.

Z Belt Replacement Procedure

Remove the Z motor mount covers from both ends of the frame.
Loosen the Z motor mount screws to slacken the belt.
Slide the belt off the motor pulley and lead screw pulley.
Route the new belt around both pulleys. The Z belt should have the teeth engaging both the motor pulley and the lead screw pulley.
Tension the belt to 90 Hz by sliding the motor mount. Tighten the screws.
Repeat on the other side.
Verify both Z belts are at the same tension. Run the gantry up and down through the full Z range and listen for binding or clicking sounds.

Common Belt Issues on the V2.4

Gantry Racking (One Side Leads)

If you notice the gantry is not level — one Z joint reaches the top before the other — the Z belt tensions are likely mismatched. Re-tension both Z belts to 90 Hz. If the issue persists, check the Z lead screw nuts for binding. Z belt tension differences as small as 2-3 Hz can cause visible racking after 200mm of Z travel.

Belt Chirping or Clicking

A chirping sound during fast moves typically means the belt is too tight or rubbing against a pulley flange. Re-check tension targets. If tension is correct, inspect the belt path for misaligned pulleys. A common culprit is the Z joint idler pulley being slightly out of alignment with the carriage pulleys.

Ghosting on One Axis Only

If ghosting appears only on X or only on Y, the corresponding AB belt may have incorrect tension. For example, ghosting on Y-axis features (vertical edges parallel to X) indicates the A belt needs adjustment. X-axis ghosting indicates the B belt needs adjustment.

Maintenance Log Template

Keep a log of your belt tension readings to track drift over time:

Date: [Date]
Print hours: [Total hours]
AB-A tension: [Hz]
AB-B tension: [Hz]
Z-L tension: [Hz]
Z-R tension: [Hz]
Notes: [Cleaning performed, adjustments made, etc.]

If you see a steady decline in tension over successive checks, the belts are settling and will stabilize after 50-100 hours. A sudden drop in tension indicates a mechanical issue — check for loose pulley grub screws or belt damage.

Summary Checklist

Check AB belt tension every 100 print hours — target 110 ± 5 Hz both sides, matched within 5 Hz
Check Z belt tension every 100 print hours — target 90 ± 5 Hz both sides, matched within 3 Hz
Clean belts with IPA every 200-300 print hours
Inspect belts for fraying, cracks, or glazing at each check
Replace AB or Z belts immediately if damaged or stretched beyond adjustment range
Always retension both sides of a pair after any belt maintenance
Keep a tension log to track drift and predict replacement intervals