Timing Belt Questions, Answered

HTD (High Torque Drive) and GT2 (Gates Tooth 2 mm) both use curvilinear tooth profiles, but at different scales. HTD pitches are 5, 8, and 14 mm, built for torque and power transmission. GT2 has a 2 mm pitch (3GT is 3 mm), built for light, high-resolution motion like 3D printers and small CNC machines. The tooth shapes differ and the belts are not interchangeable.

HTD's rounded tooth distributes load over a larger contact area, so it transmits more torque at the same width and runs quieter. Trapezoidal belts (T5, T10, AT5, AT10) use straight-sided teeth and remain common where the drive was originally designed around them — replacement means matching the existing profile.

The number is the tooth pitch in millimeters: 5M has one tooth every 5 mm, 8M every 8 mm, 14M every 14 mm. The M identifies the metric HTD curvilinear profile. Belt length is always a whole number of teeth.

A timing belt has teeth that engage matching pulley grooves, so it cannot slip — output speed is locked to input speed. A V-belt relies on friction between the belt and the pulley sheave and can slip under load. Timing belts need no tensioning after install; V-belts need periodic re-tensioning.

Both provide positive, slip-free drive. Belts are quieter, lighter, need no lubrication, and are cheaper to replace, but have a finite service life. Chains last longer but are noisier and need oil. In engines, the terms refer to the camshaft drive; in industry, belt drives are usually preferred for noise and maintenance.

Open-ended belts are supplied in continuous rolls and cut to length — used for linear drives where the belt anchors at both ends. Endless belts are molded or welded loops — used for power transmission and conveyors. Double-sided belts have teeth on both faces — used for serpentine paths where one belt drives multiple shafts.

Three types: fiberglass cord (low stretch, economical, standard), aramid/Kevlar-type cord (high strength, high energy absorption, good temperature and chemical resistance), and steel cord (maximum stiffness, highest strength, for precision linear drives). The tension member carries the working load; the teeth only position it.

Polyurethane and rubber (chloroprene/neoprene). Polyurethane offers abrasion and chemical resistance, runs clean, and suits food-grade and wash-down environments. Rubber handles higher ambient temperatures and is traditional for engine-style drives. Tooth profile and tension member matter more than material for most replacements.

Yes. Polyurethane timing belts are available in food-contact grades that resist wash-down chemicals and comply with food processing hygiene requirements.

Anti-static belts have a conductive coating or compound that prevents static electricity build-up. They are used in electronics, printing, and environments where static discharge could damage products or ignite dust.

Belt length = 2 x center distance + pi x (sum of pulley pitch diameters / 2) + (pulley diameter difference)^2 / (4 x center distance). For open-ended belts, measure the distance between pulley centers, add the engagement allowance for each pulley, and add tensioner travel. For endless belts, the length must equal a whole number of teeth times pitch.

Width is selected by the transmitted load: wider belts carry more torque at the same pitch. Match the width to the pulley face, and check the drive's rated torque against the power rating table for the pitch and width.

Check the pulley: the profile is stamped on the pulley face or listed in the machine manual. If you are replacing an old belt, match the profile, pitch, width, and length exactly — a photo of the old belt next to a ruler is usually enough for us to identify it.

Service life depends on load, speed, alignment, and environment. A properly sized and tensioned belt in a clean industrial drive typically runs for years; harsh environments (dust, heat, chemicals) shorten life. Regular inspection of teeth and tension members catches wear before failure.

Tension should be just enough to prevent tooth skip under peak load — too tight shortens belt and bearing life, too loose causes skipping and noise. The deflection method: press at mid-span and check deflection against the belt span and pitch. Most manufacturers publish tension tables by pitch and width.

Common causes: misalignment (belt running against pulley flanges), wrong tension (too loose skips, too tight whines), worn or mismatched pulleys, and pitch mismatch between belt and pulley. See our Timing Belt Noise guide for the full diagnostic.

Open-ended polyurethane belts can be cut to length with a sharp blade; the cut end needs to be square. For endless (loop) belts, welding or splicing requires equipment — we make endless belts to your exact length instead.

Use a straightedge across the pulley faces: belt span edges should sit parallel in all planes. Angular misalignment is the most common cause of premature edge wear. Check both the drive and driven pulleys for parallelism, and re-check after tensioning.

Yes. Open-ended belts are slit to any width and cut to exact length; endless belts are built to non-standard tooth counts. Custom tension members and materials are also available. See our Custom Timing Belts page for details.

MOQ varies by construction. Standard widths and common lengths are available in small quantities; custom sizes and OEM runs start from a modest minimum. Send your spec for a quote.

Yes — that is our standard practice. Matching belt and pulley dimensions from one source avoids compatibility issues and simplifies ordering and QC.

Yes. We manufacture to your drawing or sample, supply under your part number, and offer private-label branding. Sample, approve, then production — with documented QC per batch.