Timing Pulleys

Timing pulleys (also called synchronous pulleys or timing belt pulleys) are toothed wheels that mesh with the teeth of a timing belt, transmitting power without slip and keeping driven shafts in exact rotational sync. This collection covers more than 5,500 pulleys across four tooth profiles: imperial trapezoidal pitches (MXL, LT, XL, L, H, XH, XXH), metric trapezoidal (T and AT series), HTD compatible curvilinear, and high torque MX profiles that run on the same drives as Gates Poly Chain® GT® Carbon™ belts.

Sizes run from 10 to 278 teeth and from under 1/4 in to over 48 in outside diameter, in clear anodized aluminum, steel, ductile iron, cast iron, polycarbonate, and stainless steel. Bore options include finished inch and metric bores, minimum plain bore for machining to size, and Taper-Lock® bushed styles. Every pulley is machined from solid stock, never sintered or powdered metal.

How to Choose a Timing Pulley

Match four things to your belt: pitch (the tooth spacing), tooth count, belt width, and bore. The pitch and width must match the belt exactly. The tooth count sets the pulley diameter and the drive ratio. If you are replacing an existing pulley, the part number usually encodes all four, and the cross reference tables on each product page match competitor numbers directly.

Frequently Asked Questions

What is the difference between trapezoidal, HTD, and MX timing pulleys?

Tooth profile. Trapezoidal pitches (MXL, XL, L, H) use straight sided teeth and are the standard for instrumentation and light industrial drives. HTD compatible pulleys use a rounded curvilinear tooth that carries more load. MX profiles are high torque curvilinear designs for low speed, high load drives, and run on the same belts as Gates Poly Chain GT Carbon and Continental Synchrochain Carbon systems.

How do I identify the pitch of a timing pulley?

Measure the distance between the centers of two adjacent teeth. Common imperial pitches are MXL (0.080 in), XL (0.200 in), L (0.375 in), and H (0.500 in). Metric pitches are named by the measurement: 3 mm, 5 mm, 8 mm, and 14 mm. Count the teeth and measure the bore to complete the identification.

Can I mix pulley and belt brands on the same drive?

Yes, when pitch and width match. Timing belt pitches are standardized, so a pulley from this collection runs belts of the same pitch and width from Gates, Continental, Mitsuboshi, Optibelt, and other manufacturers.

Do timing pulleys need flanges?

At least one pulley in a drive is usually flanged to keep the belt from walking off, typically the smaller pulley. Long center distances, vertical shafts, and any drive where the shafts are not perfectly parallel need flanges. Unflanged pulleys can be flanged with press on flanges from the timing pulley flange collection.