The Right Timing Belt for the Right Application: 7 Frequently Asked Questions

Choosing a timing belt can seem like a daunting task, they’re more complicated than your standard conveyor belt. With multiple fabrication options, tooth profiles, dozens of backing/cover materials, and several layers on the belt, the whole process can be overwhelming.

Every timing belt application is different; there’s no cookie cutter selection model to follow. Timing belt solutions need to be determined on a case-by-case basis. And, in order to select the most efficient belt for your plant, you’ll want an expert’s opinion on the matter. That’s why the professionals at Belt Power created this article: to guide you through answers to our most commonly asked timing belt questions.

Timing belt frequently asked questions:

1. How do I know when I need a truly endless belt vs. a welded endless belt?

• To answer this question, we will need to know what your timing belt is being used for. If your application requires the belt to transmit power, you will need a truly endless belt.
• Welded endless belts are fine for more common conveying applications. They carry components, ingredients, finished products, cartons, etc. on top of the belt. The “timing” in timing belt indicates they are employed mostly to synchronize delivery of these goods in the production, packaging, or freight-loading process.

2. What cord type should I use?

• Again, different cord types are designed for different applications. Steel is typically the tensile cord material of choice, especially in power-transmission applications. It provides the highest tooth shear strength of any cord material.
• Kevlar cord is an effective alternative and is often used in metal detecting applications and when steel does not offer sufficient impact resistance for items dropped onto the belt. Kevlar CANNOT be used in wet or humid environments, cords constructed with aramid fibers absorb moisture, causing them to stretch and contract. These changes in fiber length can cause problems in belt performance, such as slippage and binding, altering the engagement between belt and sprocket teeth.

3. What is PAZ/PAR and why do I need it?

• PAZ/PAR are nylon fabric coverings that are molded to either to the back (PAR) or the tooth side (PAZ) of timing belts. The nylon facings reduce the coefficient of friction on both sides. PAZ, optimizes the interactions between the timing belt teeth and the pulley. Less friction will result in quieter belt operation and longer tooth life. PAR reduces friction between the timing belt and the product being conveyed. This functionality is especially key in accumulating applications and when easy product release from the belt speeds the operation.

4. What are the advantages and disadvantages of a pin splice?

• Pin splicing allows belts to be removed from and installed onto the conveyor without disassembling the machine. Pin-spliced belts can be replaced in as little as 10 minutes. This can save as much as eight hours and some cases days of valuable production time.
• However, pin splicing reduces the timing belt’s tensile strength, preventing its use in power-transmission applications. (Note: welded endless belts are about half as strong as truly endless belts; pin-spliced belts are about half as strong as welded).

5. What is the difference between a molded cover and a spliced cover?

• Molded covers offer superior performance, 9 times out of 10 when there is failure it is at the splice location. Molded covers are continuous; they contain no seams that can fray or catch, causing failure after repeated use. The chemical properties of some rubbers and some other materials are not conducive to molded covers and can only be applied with spiced covers. One disadvantage of molded covers is the lead time. Manufacture and delivery of these belts can take 4 to 6 weeks.

6. How do I find out my timing belt’s tooth style?

• The best way to determine the tooth style of your belt is by using a timing belt tooth gauge; contact Accurate Industrial for your free gauge.
• If you do not have a tooth gauge, you can determine the tooth style by observing tooth shape (rounded or trapezoidal) and measuring the pitch of the teeth (the distance between the centers of two adjacent teeth).

7. What type of cover (also referred to as backing) is best for my application?

• For a full discussion of this topic and a comparison of all timing belt cover options, visit https://www.beltpower.com/products/timing-drive-belts/timing-conveyor-belts/.
• Use this guide to determine the cover/backing type that will work best for you:

We’re here to ensure your success

The experts at Belt Power have a wealth of timing conveyor belt experience and industry knowledge. They can guide you through the selection process to ensure you’re equipped with the most suitable and efficient timing conveyor belt to meet the specific needs of your application. If you’re in need of a new timing belt, would like to make changes to an existing timing belt, or have any questions at all; call us toll free at 800-886-BELT (2358) or contact us today.