How to Choose Excavator V Belt?

Monica

Jun. 30, 2025

How to Identify a V-Belt? | Megadyne Group

A V-belt is a wedge-shaped belt manufactured out of a rubber compound, reinforced with a tensile cord specifically engineered to transmit power into movement. V-belts can be found in driving mechanisms, such as engines in air compressors, fans, and pumps. They are available in a variety of sizes and materials to meet the needs of particular applications.

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V-Belt Product Types

There are several possible types of V-belts available:

Light Duty - Suitable for light-duty applications normally using fractional horsepower motors.
Classical Heavy Duty - Wide range of sizes.
Molded Cogged - Cogs allow the use of smaller diameter pulleys and provide heat dissipation; Raw Edge Sidewalls prevent slippage.
Wedge - Narrower, deeper profile with higher power capacity than classical v-belt; allows for smaller, more compact drives.
Wedge Cogged - Same properties as Wedge, but cogged for greater flexibility and heat dissipation.
Banded – Two or more v-belts joined to form a single belt allowing the belts to function as a single belt with equal load distribution and wear.

How to Identify a V-Belt?

Belts with Branding

If the branding on the v-belt is still intact, the easiest way to identify it is to simply read the part number. Unfortunately, after hours of use, the brand is often worn off and not legible. In this case, it becomes necessary to take note of the dimensions of the belt.

Belts without Branding

You then need to find the measurements for your V-belt. The following steps will allow you to do so:

Step 1: Determine Belt Cross Section

V-belt cross sections are categorized based on their top width and depth measurements. Each width/depth combination is labelled using a letter of the alphabet. For example, v-belts with 21/32 in. width and 7/16 in. depth are labelled a "B" belt. Specially designed Browning V-Belt Rules are also available with a gauge to help you select the correct belt type.

Step 2: Identify Belt Construction

V-belts are available in either wrapped or raw edge styles. A conventional wrapped v-belt will have an envelope of rubberized fabric covering the belt. A raw edge cogged v-belt will have exposed rubber sidewalls and moulded cogs on the bottom that resemble teeth. The following characteristics may also be present, depending on the construction type:

Rubberized fabric cover – Cover envelopes the entire belt and protects the belt core.
Top fabric – Provides heat and oil resistance.
Load carrying section – Cords (also known as tensile members) give the ability to transmit power and ensure uniform load distribution.
Compression section – Elastomer resists compression fatigue and dissipates internal heat build-up, providing firm lateral pressure against the sheave/pulley sidewall and distributing the load to the cords.
Precision molded cogs – Provide additional flexibility, allowing for the use of smaller pulley diameters, and aiding in heat dissipation.

Step 3: Measure V-belt length

The most difficult part of identifying a v-belt is measuring the length. There is no precise method that is practical to perform in the field for v-belt measurement. Precise measurement requires a measuring fixture with pulleys of prescribed dimension and the ability to apply a specific tension to the belt according to ARPM (Association for Rubber Product Manufacturers) standards for the given belt section.

Additionally, there are several terms used in the industry to describe length (e.g. inside length, outside length, pitch length, effective length) making it very confusing.

Some belt providers instruct end users to utilize tapes to measure outside length. While this method can approximate belt length, it can still be off by inches. If the drive has ample installation and take-up range, using a tape can yield a belt that will fit the drive in many cases, however, there is no guarantee it is the optimum length designed for the drive.

Contact Megadyne Application Engineering, who will work with you to perform the drive analysis and ensure the belts we deliver are the best choice for your application.

Step 4: Label the Drive

Finally, to avoid the issue of identifying the v-belt each time it needs to be replaced, a good maintenance practice is to properly label the drive with the correct belt part number. Use an adhesive sticker or any type of permanent signage where you can easily read the belt part number, making it easy to obtain belts in the future. Recording the date when the belts were installed can also enhance your maintenance program with increased uptime by knowing when to replace belts before they fail.

Quality V-Belts From Megadyne

V-Belt Code Guide: How to Read V-Belt Numbers - Blog

A machine with two shafts definitely needs to transmit power from one shaft to the other. In other to carry out this task seamlessly, the use of power transmission devices such as chains, gears, and belts, in particular, are adopted. Of all mentioned means, one is highly flexible, seamless, effective, and also an efficient power transmission device, which is popularly known as V-Belt.

What is V-Belt?

“V-belts” as it sounds, was coined from the letter V looks of this particular belt. We can also say its name is gotten from its trapezoidal shape. The V-Belt helps to transmit force out from the engine straight to the ancillary elements, which also includes the alternator. The primary source of the seamless task done by the V-Belt comes from the rotation of the crankshaft, which helps to drive one or two units of an engine.

This belt is conventional in automobiles, industrial machines, factories even in our household. The V-Belt was made from twisted synthetic fibrous tensile, which is compressed by synthetic rubber, this strengthens the belt and makes it more flexible. Compared to the other power transmission devices, V-Belts does not require any form of maintenance or lubrication, as it is the case for chains.

In industries and some manufacturing factories, the majority of the machines you get to see there are operated with the V-Belt as it is the primary power transmission device that also provides a suitable combination for loading of the bearings, speed, traction, and even longevity.

It is widely known that V-Belts solve slipping and alignment problems, it can never go wrong while in operation compared to other power transmission devices.

V-Belts can also be found in modern automobiles (In the past, roller chains were used to transmit power in vehicles) and in our households such as washing machines and lawn mowers. As long as we make use of one or two machines regardless of its size, V-Belt keeps it in motion.

Types of V-Belts:

There are three common type of V-belts, and they are classified by their dimensions:

1) Classical V-Belt - Classified by its dimensions ranging from A to E

The classical V-Belt is the most common of all V-Belt types, and it has been in existence even before other V-Belt types. This type of V-Belt has a broad scope of usage in different areas such as Agriculture, Industrial Machinery, ventilation etc. and this is due to the fact that it covers a load range from 1 horsepower to 500 horsepower. There is no doubt that the Narrow Wedge is more efficient than the classical V-Belt; however, they work seamlessly with higher bearing loads and have a high tolerance for adverse operating conditions.

2) Narrow Wedge - Classified by its dimensions ranging from 3V, 5V, and 8V

This type of V-Belt is more efficient than the Classical type as they have the most significant degree possible for the distribution of force and load transfer, which is the main advantage over the Classical type. Narrow Wedge is able to transmit three times the Horsepower a classical V-Belt would in the same drive space; they are very suitable for drives at high speed and its well-known for its sturdy, compact size. Unlike the classical V-Belt, Narrow Wedge can handle drives from 1 horsepower to 1,000 horsepower.

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3) Fractional Horsepower - Classified by its dimensions ranging from 2L, 3L, 4L, 5L.

Unlike the two mentioned types of V-Belts, the Fractional Horsepower is different in operation as it is only designed for light loads and is often used as a single belt on drives that run at one Horsepower or even less. This type of belt is what you see in domestic machines popular in household equipment such as washing machines, fans, and refrigerators. Fractional Horsepower can never be used on any heavy-duty industrial machinery even if it fits perfectly well.

Note: Unit of Measurements Depending on the type of belts and the origin of the manufacturer, some belts have a unit of measurement in milimeters (mm) whilst others are measured in inches. For instance, classical belts and American standard type belts are measured in inches, belts in the modern range are mostly denoted in mm.

How to Measure V-Belt

There are times when you will need to replace your V-Belt due to its natural wear and tear. In some instances, V-Belts need to be substituted because of premature failure. You could prevent this by looking out for these warning signs.

To order the correct replacement V-Belt, it is as simple as taking a few quick measurements as shown in the steps below:

Step 1: Determine the type of belt you have. You need to measure the width of your belt. We have different types of belts, Type A, Type B, with different measurements. So you want to know the width of your belt first

Step 2: Measure the length of your belt. You can do this by using a cloth or a measuring tape. To get a correct length, place your belt on a steel tape.

Step 3: Subtract from the outside measurement. If you know the type of V-Belt you have already, there will be need to subtract a specific inch from the size to select the correct V-Belt

For type A, you subtract 2 Inches

For type B, you subtract 3 inches.

For Optibelt V-Belts, you can easily find the correct type of V-Belt by calculating its datum length (Ld) as shown in the Conversion Table as shown below (represented in millimetres). The datum length determines the Part Number of the V-Belt.

To be precise, you would need to determine if the measurement is taken from the inside length (Li) or outside length (La) of the V-Belt.

Example:

If we measured the outside length of a SPA belt and it is measured at La = mm.

In the highlighted table above, we can see that the formula for SPA is La= Ld+18.

To calculate the datum length, you subtract 18 from the outside length of mm:

Ld = -18 = .

Based on the calculation above, we now know that the Part Number of the V-Belt is SPA .

How to Read V-Belt Codes

V-Belt codes allow us to identify the belt profile and its length. Follow the simple steps below to learn how to read V-belt codes:

Step 1: Outside the surface of your belt, you will find the prefix e.g. B, 3L.. etc. This is also known as the belt profile.

Note: Prefix Depending on the manufacturer, the belt profile on the surface of the belt can be represented by a letter such as A, B etc. or an alphanumeric value, such as 3L, 4L etc.

Step 2: After the belt profile, read the two or three digit number that follows to identify the length of your belt. Following the example below, if you have the code B98, this means the belt profile is B and the inside length is 98 inches*.

The code B98 shows the belt profile, B and its inside length at 98 inches*

V-Belt in Motion

Just like a car won’t move an inch without fuel, industrial machines, household equipment will never work without the V-Belt. This tells how important it is to have V-Belt in machines. Remember in manufacturing industries, motion is needed for machines to carry out designated tasks and the most efficient way to give two end of shafts is where the V-Belt comes into play. Its benefits cannot be underestimated.

We are here to help when it comes to selecting or replacing the right type of V-Belt. As an authorized distributor of Optibelt, we provide a range of V-Belts that suits your need. Alternatively, if you would like to find out more information about V-Belts, get in touch with us below:

* Previously, we mentioned that the belt length was 98mm. Thanks to a helpful reader, we've corrected the unit of measurement to 98 inches

Are you interested in learning more about Excavator V Belt(es,it,in)? Contact us today to secure an expert consultation!

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