Belt Tension & Adjustment

1. Power off the printer (P2S: also remove the top glass cover)
2. Loosen the four belt-tensioner screws at the back 1–2 turns; do not remove them
3. Move the toolhead back and forth several times, also along Y (P2S: as wide as possible, 3–5 times); X1, P1 and H2: finish at the rear end
4. Retighten the four screws without over-torquing; the springs set the tension
5. Power on and run Vibration Compensation

1. Raise the X gantry to mid height and power off
2. X belt: loosen the screw on the back of the toolhead one turn (H2.0), move the toolhead along X three times, retighten
3. Y belt: remove the small cap at the front of the base, loosen both screws one turn, move the bed back and forth three times, retighten
4. Z belt: loosen the two screws near the right column one turn, home, move Z up and down once, retighten
5. Power on and run Vibration Compensation from Settings → Maintenance → Calibration

A1 Mini: follow Bambu's A1 mini belt tensioning guide.

Pluck the belt like a guitar string:

• Dull thud: Too loose. Tighten.
• Low twang (bass note): Good.
• High ping: Too tight. Loosen.

Community rule of thumb, not from Bambu's documentation. Use the built-in check when possible.

• Visible cracking, fraying, or missing teeth
• Belt has been significantly over-tensioned (stretched/delaminated)
• Tension keeps dropping between checks (belt has stretched past recovery)

Belts are a consumable: replace them when they are broken or worn. Bambu sells model-specific XY belts (P2S: 1444 mm long, 7 mm wide; H2D: 1824 mm, 9 mm wide; H2S: 1836 mm, 9 mm wide), so order the one made for your printer.