HTD3M HTD5M Rubber Timing Belt Closed Loop Power Transmission Belt 10mm 15mm Wide

Measure the center distance between your two pulleys, then calculate the required belt perimeter: Perimeter ≈ 2 × center distance + (π × sum of pulley pitch diameters / 2). For HTD3M, tooth count = perimeter ÷ 3; for HTD5M, tooth count = perimeter ÷ 5. For example, a 171mm HTD3M belt has 57 teeth. When in doubt, size up one increment and use a tensioner to take up slack. If you're replacing an existing belt, measure the old belt's outer circumference and count the teeth directly.

HTD3M has a 3mm tooth pitch and is generally used in lighter-duty, higher-speed applications — 3D printers, small CNC machines, and robotics where positional accuracy matters most. HTD5M has a 5mm tooth pitch and is typically chosen for higher-torque, moderate-speed drives such as larger CNC routers, conveyor indexers, and power transmission systems. If your machine already specifies one profile, match it exactly — the two are not interchangeable.

Load capacity depends on belt width, tooth profile, operating speed, and the number of teeth in mesh. Generally, 10mm-wide HTD3M belts are suited for lighter loads (typically up to ~50–80N working tension in most hobby CNC applications), while 15mm-wide HTD5M belts can handle significantly higher torques. For safety-critical or high-cycle industrial applications, contact us to confirm suitability for your specific load requirements.

The rubber compound generally provides good resistance to moisture and moderate temperature ranges, making these belts suitable for most indoor workshop and light outdoor enclosure environments. They are not recommended for prolonged immersion in water, direct contact with oils or solvents, or continuous UV exposure without shielding. For harsh outdoor installations, consider adding a belt guard or cover.

HTD3M belts require HTD 3M pulleys (3mm pitch, rounded curvilinear tooth profile). HTD5M belts require HTD 5M pulleys (5mm pitch). These are not compatible with GT2, GT3, MXL, XL, or L-series pulleys, which use different tooth geometries. Always verify the pulley profile designation — not just the pitch — before ordering, as some suppliers label pulleys by pitch only.

Divide the millimeter value by 25.4. Quick reference examples: 171mm ≈ 6.73", 225mm ≈ 8.86", 300mm ≈ 11.81", 360mm ≈ 14.17", 450mm ≈ 17.72", 531mm ≈ 20.91". This is useful when cross-referencing with imperial-spec machine documentation or sourcing guides that list belt sizes in inches.

Most single-axis machines (one motor driving one belt loop) require 1 piece. CoreXY 3D printers, H-bot systems, and machines with mirrored or dual-axis belt paths typically require 2 pieces of the same size. We offer both 1-piece and 2-piece quantity options for every size variant so you can order exactly what your build needs without overpaying for extras.