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Cold Formed Timing Belt Pulleys Overview

June 15, 2021

Timing Belt

Timing belt pulley drive systems use teeth and grooves like a chain and sprocket to lock the drive and driven pulley together. These systems keep alignment by maintaining the engagement of precise teeth and pockets between the belt and pulley. The belt allows for a smooth and quiet power transmission while the teeth and pockets maintain alignment by not allowing the belt to slip on the pulley.

Grob, Inc. engineers our cold-formed timing belt pulleys with superior precision and surface finish to deliver high-performance, smooth, and long-lasting pulley systems. Our innovative Grob Rolling process has delivered reliable results for over half a century and continues to produce the highest quality timing belt pulleys available.

What is a Timing Belt Pulley?

Timing Belt Pulley

A timing belt pulley has teeth or pockets around the diameter of the pulley body. The specialized design maintains accurate timing by locking the pulleys in the system using a belt with similar teeth and pockets. This allows for the two rotating shafts to be locked together allowing them to always rotate at the same speed and hold position alignment for the life of the system.

Timing belt pulley systems can span larger reaches and require little to no maintenance and oiling, unlike gear or chain systems. Additionally, they can allow for easier changing of gear ratios by simply changing pulley sizes & getting the right size belt. Timing belt pulleys also run significantly quieter and smoother than chain and gear-operated timing systems.

Pulley Options and Applications


A timing belt pulley won’t suit every situation. The intended use case will determine the right pulley system for your needs. Some of the most popular pulley options include:

  • Multi-ribbed pulley. This compact pulley offers the ability to produce high torque in a small space. It makes an ideal choice for chair lifts, microwaves, dryers, and fans where timing is not required.
  • Variable speed pulley. This pulley adjusts its size to vary the gear ratio and the driven pulley speed. Variable speed pulleys are used when system speeds need to be changed often and quickly. These pulleys are used in machinery where timing is not required.
  • V-belt pulley. Known for its distinct V-shaped groove, the V-belt pulley provides a popular and inexpensive pulley option. Engines rely on V-belts to transfer force to ancillary components, such as hydraulic pumps and alternators where timing is not required.
  • Timing belt pulley. Timing belts are used where timing needs to be held between the drive and driving pulley. These types are used in systems that require speed and position accuracy. They are used for engine timing and in machines like printers and automation equipment.

How to Choose a Timing Belt Pulley

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Cold Rolled Timing Belt Pulleys

Sizing and materials are important factors when determining the ideal pulley for an application. The timing belt size based on loads and speed will determine the width and tooth count pulley one would need. Otherwise, the gear ratio or number of teeth between the 2 pulleys with be what is needed to have the correct speeds between the driven and driving gear. Adjusting the tooth count will adjust the ratio and the size of the pulley to fit the application.

Timing belt pulleys are available in various materials. Determining the ideal material depends on the operating horsepower, temperature, and environment.

  • Aluminum timing belt pulleys are prevalent for their light weight, durability, and strength. Aluminum is the preferred material for systems with significant horsepower, extreme heat, and high speed.
  • Steel is another common timing belt pulley material known for its stability at extreme temperatures and performance in harsh conditions. It is readily available and has high strength and durability to handle heavy loads. This is the heaviest option.
  • Plastic timing belt pulleys are the least expensive but also the least durable option. They are affordable and lightweight, making them a preferred choice in many standard environments, but also best in low-speed & low-stress systems. They perform very well in light-duty machines, such as printers and RC toys.

Cold Formed Timing Belt Pulleys from Grob Inc.

Timing belt pulleys are essential in many systems that require precise positioning and alignment. They offer a smooth and quiet drive system with minimal to no maintenance. When choosing an ideal pulley, consider the application, sizing, and material for the best performance.

At Grob, Inc., our Grob Rolling Process minimizes material waste and allows us to produce high-performance timing belt pulleys. Our pulleys will also have a great surface finish that will extend the belt’s lifetime. With more than 2200 design profiles and over 70 years of experience, you can count on us to deliver a product that meets your expectations.

To see how our cold-formed timing belt pulleys can benefit your operation, please contact us today.