Can I 3D print timing belt pulleys?

Yes, for light-duty applications. Print in PETG or Nylon for durability. PLA works for prototyping but wears quickly. Use at least 4 perimeters and 50%+ infill for strength. The tooth profile may wear over time with heavy use.

What tooth count should I use?

Minimum 12 teeth for smooth belt engagement. 16-20 teeth is standard for 3D printers. Fewer teeth = smaller diameter but more belt bend stress. More teeth = larger diameter, smoother operation but takes more space.

Do I need flanges on printed pulleys?

Yes, flanges prevent the belt from walking off the pulley. Add 1-1.5mm flanges on both sides that extend 1mm above the tooth tips. Without flanges, the belt can gradually shift sideways and come off.

How accurate do the tooth profiles need to be?

GT2 teeth have a specific rounded profile for smooth engagement. FDM printing approximates this shape. For critical applications, orient the pulley so the teeth are in the XY plane. Resin printing gives more accurate tooth profiles.

3DPrintCalcs

Pulley Calculator — Timing Belt Pulley Design

Design timing belt pulleys with correct tooth profile and pitch diameter.

Belt Type

Tooth Count

Belt Width

Bore Diameter

Shaft hole diameter

Flange Height

How We Calculate This

Pulley Dimension Formulas

Pitch diameter = (Tooth count x Belt pitch) / Pi
Outer diameter = Pitch diameter - 2 x Tooth depth
Pulley width = Belt width + 2mm clearance
Flange diameter = Pitch diameter + 2 x Flange height

The pitch diameter is where the belt centreline sits on the pulley. The outer diameter is the root of the teeth. Belt engagement happens at the pitch circle, so this determines the effective drive ratio between pulleys.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.