Timing Belt Drive Installation & Maintenance

Finding the Right Timing Belt Drive

Getting the drive design right is the first step toward long belt life.

• Pulley Diameter – The small pulley should be no smaller than the belt width to avoid excessive tracking forces.
• Teeth in Mesh – Ensure at least 6 teeth are engaged with the pulley grooves.
  • If fewer than 6 teeth are engaged, apply a correction factor:
    • 5 teeth → 0.8 × power rating
    • 4 teeth → 0.6 × power rating
    • 3 teeth → 0.4 × power rating
    • 1–2 teeth → redesign the drive
• Flanged Pulleys – At least one pulley must be flanged when center distance is ≥ 8× the small pulley diameter. For vertical shafts, both pulleys should be flanged.
• Noise Considerations – Belt speed, tension, and width all contribute to noise; higher values increase sound levels.
• Long Center Distance – Prevent belt sag on the slack side to avoid tooth-to-tooth contact.
• Idlers – Avoid if possible. If required, place them on the slack side. Inside idlers must have teeth unless very large in diameter; flat idlers must be flat, not crowned.
• Tension – Timing belts require less initial tension than V-Belts. Correctly installed belts should run their full life without re-tensioning.
• Rigid Frame – Prevents center distance changes under load.

Installation Best Practices

• Check Alignment – Shafts must be parallel, and pulleys must be aligned within ¼° or 1/16″ per foot of span. Use a straightedge.
• Inspect Pulleys – Replace if worn, rusted, or damaged.
• Avoid Forcing Belts – Never pry or roll belts onto pulleys. Move pulleys closer for installation, then adjust for tension.
• Correct Tensioning – Follow Bestorq’s Timing Belt Tensioning guidelines for optimal life and minimal noise.

Maintenance and Care

Proper maintenance goes beyond tension checks—it includes avoiding damage during operation and handling.

• Avoid Crimping – Never bend belts smaller than their minimum recommended pulley diameter.
• Prevent Ratcheting – Too little tension or variable center distance can cause teeth to skip. Increase tension gradually until this stops.
• Keep Drives Clean – Debris in pulley grooves can puncture the belt or cause tracking issues.
• Control Contaminants – Oil and grease won’t cause slip but will degrade belt material over time.
• Manage Loads – Even small load increases can dramatically reduce belt life; doubling the load can cut life to just 5–10% of expected.

Proper Belt Storage

Improper storage can damage belts before they’re ever installed.

• Temperature & Humidity – Store below 85°F and 75% relative humidity. Avoid temperatures above 115°F. Every 15°F increase cuts life by ~50%.
• Rack Storage – Use saddles with diameters ≥ the minimum recommended pulley size.
• Idle Equipment – If unused for 6+ months, relax tension and store in proper conditions.
• Stacking & Nesting – Gentle “C” nesting is fine; avoid forcing belts inside each other or bending sharply.
• Protection from Light & Chemicals – Keep away from sunlight, ozone sources, solvents, and chemical vapors.
• Avoid Floor Storage – Unless in protective containers.
• Prevent Deformation – Avoid sharp bends, crimping, or hanging on small pins.