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What is a Timing Belt Pulley?

what is a timing belt pulley

Pulleys are one of the most common pieces of equipment found in applications around the workplace and in the home. Both your hotel elevator and sewing machine utilize various pulleys to complete necessary functions. Due to the assortment of needs, multiple pulley variations have been created and manufactured according to each application.

Timing belt pulleys are one of the most popular pulleys on the market, known for the unique ability to prevent misalignment and maintain accurate timing during operation. In the content below, we explore timing belt pulleys and discuss basic definitions, common uses, and pulley materials. Finally, we provide an overview on selecting the best timing belt pulley option for your application.

Timing Belt Pulleys Defined

A timing belt pulley is a specialized pulley system with teeth or pockets along the outside of the pulley body’s diameter. Like traditional pulley systems, timing belt pulleys are driven by frictional forces between the belt and pulley surfaces. The teeth or pockets on the outside of the pulley are not used for power transmission. Rather, they engage the pulley belt, assisting with timing and averting misalignment.

What Are Timing Belt Pulleys Used For?

Timing belt pulleys are utilized when two shafts need to be precisely linked for homogeneous rotation. Most traditional power transmission belts and pulleys are smooth, without teeth or pockets. At times, the smooth belt can slip off the track, causing one shaft to turn while the other sits dormant. Timing belt pulleys eliminate this concern as teeth or pockets keep the pulley firmly attached to the belt during operation.

Timing Belt Pulley Vs. Other Options

As mentioned, timing belt pulleys are not the only variation available. In fact, depending on your specific applications, selecting another pulley may be ideal. Multi-Ribbed, Variable Speed, and V-Belt Pulleys are among the most common options.

Multi-Ribbed Pulleys

Multi-Ribbed Pulleys are found in a multitude of applications, including fans, dryers, microwaves, and chair lifts. Designed for power in compact environments, Multi-Ribbed Pulleys are designed for higher torque in minimal space.

Variable Speed Pulleys

Unlike Multi-Ribbed Pulleys, Variable Speed Pulleys are commonly utilized in larger applications, such as heavy machinery. As the name implies, Variable Speed Pulleys are designed to change rotating shaft speeds, increasing or decreasing revolutions per minute as needed.

V-Belt Pulleys

Named for tapered pulley sides that form a V-shaped groove, V-Belt Pulleys are a transmission belt that transmits the force of an engine to ancillary components, including alternators, hydraulic pumps, etc. Due to their relatively low-cost, V-Belt Pulleys are a popular option.

Timing Belt Pulleys

Prized for their reliability, these pulleys are known for minimal operation issues and strictly maintained system timing. Furthermore, unlike many pulleys, belts and gears do not come in direct surface-to-surface contact, eliminating the need for constant lubrication. Finally, Timing Belt Pulleys drastically reduce operation noise as opposed to chains or gears.

How Do I Choose a Timing Belt Pulley?

Environmental Considerations

Utlimately, selecting the proper timing belt pulley for your application begins with an environmental audit. Does your working environment have specific food-safety requirements? Should the system be anti-static for electronic applications?

Consider all environmental conditions that may impact the chosen timing belt pulley. Customary conditions that often impact pulley choice include:

  • Temperature – extreme heat or extreme cold
  • Large dust particles or debris (opportunity for increased tension and excess wear)
  • Grease or oil exposure
  • Presence of ozone gas

Acknowledging environmental concerns allows you to select proper materials. For example, if your timing belt pulley will be operating in the presence of ozone gas, select a urethane or rubber belt with an ozone block chemical. A urethane belt is also often required in environments with excess grease or oil exposure.

Sizing Considerations

A multitude of sizing variables must be considered before selecting the right timing belt pulley for your application, including width, pitch, number of teeth, timing marks, and lightening holes. For assistance in selecting the best pulley, don’t hesitate to reach out to experts who are ready to guide you an ideal choice.

Material Considerations

As mentioned, specific environmental conditions will play into the selection of pulley materials, the most common being aluminum, steel, and plastic. Each material best fits various environmental conditions and system requirements.


This is one of the most frequently utilized materials in pulley fabrication. Aluminum is light and durable, excellent for high horsepower drive systems. The tensile strength and durability of aluminum allow for high load capacity while preventing deformation during use. Furthermore, aluminum is often utilized in extreme temperatures, especially intense heat.


Widely available, steel is also commonly utilized. Known for constancy in harsh environments, steel remains solid over time. Like aluminum, steel’s high tensile strength allows for heavy load capacity. Finally, steel remains stable within temperature sensitive environments, including intense heat or cold.


This material is often preferred due to its lightweight nature and affordability. Plastic timing belt pulleys do not undergo oxidation, therefore avoiding regular coating requirements.Furthermore, plastic is the ideal material for light applications in “normal” environments where little maintenance is desired.

Customizable Timing Belt Pulleys with Illinois Pulley & Gear

At Illinois Pulley & Gear, our goal is to provide the finest quality products to our customers efficiently and economically. As a custom pulley manufacturer with over 90 years of combined experience, we provide exactly what you need, the first time.

We value honesty, trust, and going beyond what is expected. Our team is known for prompt customer service – we listen first, guide you to an excellent solution, and deliver.

On client, Eric Brose, Project Manager at Technico Precision Manufacturing, Inc., wrote, “Illinois Pulley & Gear has provided precision machining services for us for over 5 years. They have been consistently reliable, professional, and flexible from quoting to manufacturing and delivery.”

This is our promise. To get in touch with our team today, feel free to call 847.407.9595 or reach out via our online contact form.