Roller Chain Strength

Written by: Connor Eversen

Published on July 9, 2025

Time to read 6 min

Table of contents

Roller Chain Strength Explained Roller Chain Tensile Strength Roller Chain Working Load Strongest ANSI Roller Chains Things That Improve Roller Chain Strength Examples Failure Due To Roller Chain Strength

Roller Chain Strength Explained

Roller chain strength refers to the capacity of a given roller chain, determined by its material, dimensions, and specific manufacturing processes that influence its strength. This article aims to provide an in-depth explanation of roller chain strength and its potential to be detrimental to selecting the correct roller chain size for your application. We take a deep dive into the two most common industry terms related to roller chain strength: tensile strength and working load. We also compiled a list of the strongest roller chain sizes based on their corresponding ANSI part numbers. Here at USA Roller Chain, we aim to educate our clients on roller chains and other industrial power transmission components, enabling them to achieve the best outcome and value for their specific needs.

Roller Chain Tensile Strength

Tensile strength is defined by the amount of force required for a chain to fail. However, three different sub-terms or measurements are taken when testing for tensile strength. The chart below (Figure 1.1) shows a visual representation of the three different benchmark measurements.

Minimum Tensile Strength – This is the lowest amount of force required to break a given chain out of a series of tensile tests conducted on a particular size of roller chain. Typically, multiple tensile tests are performed per run on each size to ensure the measurement is applicable.
Average Tensile Strength – This is the median amount of force required to break a given chain out of a series of tensile tests conducted on a particular size of roller chain.
Maximum Tensile Strength – This is the highest amount of force required to break a given chain out of a series of tensile tests conducted on a particular size of roller chain.

Figure 1.1

Roller Chain Working Load

The definition of a roller chain working load is the amount of linear pull exerted on a chain by a drive. This load measurement is calculated using different formulas and with a safety factor of 70% of the tensile strength. Since a working load is the specific chain size designed to operate under a range of applications, it is imperative to use this load rating when creating a drive based on roller chain strength. Refer to the working load/chain pull equations below for more details.

Note: Output values are in kN, not LBS

Elongation Chart

Points O – A: Elastic region
Point A: Limit of proportionality for chains; there is no obvious declining point, as in mild steel
Points A – C: Plastic deformation
Point B: Maximum tension point
Point C: Actual breakage

The elongation chart (Figure 1.2) visualizes how the strength of a roller chain is mapped. Point B is the maximum tension point, which is the maximum tensile strength. In certain circumstances, points B and C will occur simultaneously. After several chain breakages, a tensile strength graph can be formed to show a normal distribution (Figure 1.1).

Figure 1.2

Strongest ANSI Roller Chains

When it comes down to roller chain strength, we also wanted to compile a list of the strongest ANSI Standard roller chains on the market today. We also offer the strongest metric roller chain. In terms of roller chain strength, these chains have undergone specific processes to improve strength, fatigue resistance, and lifespan. The strongest roller chains we offer are designed to operate in the most extreme and harsh applications on earth. For additional information or pricing, please contact our customer service team, and we will be happy to assist you.

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Things That Improve Roller Chain Strength

things that improve roller chain strength

When it comes to improving roller chain strength, several processes and features contribute to enhancing the overall strength of a roller chain. For more details about our high-strength standard series chains, please visit our page "What Makes a Roller Chain Premium."

Heat-Treated Components - Often, manufacturers implement various heat-treatment procedures on a roller chain to enhance the chain's strength. This typically includes carburizing (case hardening), induction hardening, quenching & tempering. Performing a heat treatment on roller chain components not only enhances roller chain strength but also improves fatigue resistance and controlled distortion. Often, the most beneficial treatment in terms of heat treatment for improving roller chain strength is when manufacturers quench and temper the pins to produce a chain with through-hardened pins.
Shot peening - This process enhances roller chain strength by creating compressive residual stress on components that counteract tensile stresses. It works by blasting the surface of a chain component with small spherical metal balls (shot), and also improves fatigue resistance and reduces cracking due to high shock loads.
Superior Steel Materials - When it comes to the material of roller chains, not every manufacturer uses the exact same quality or grade of raw steel. When a chain manufacturer uses higher grades or specific alloys for specific components of a roller chain, it can significantly enhance roller chain strength when combined with other processes, such as heat treatment and shot peening.
Pre-Loading - This procedure doesn't directly improve a roller chain's tensile capabilities; however, it enhances roller chain strength by allowing it to withstand loads within its designated parameters more evenly as the load is distributed across the components.
Thicker Side-Plates - This type of roller chain is commonly known in the industry as heavy roller chain; it has thicker side plates, which don't increase tensile strength but do improve the actual fatigue strength. This means that this chain is capable of withstanding higher shock loads over an extended period without experiencing failure.
Wide-Waste Side Plates - Some roller chains utilize a unique side plate design that is wider in the center line portion of the plate to improve tensile strength and fatigue strength. This specific feature can significantly enhance roller chain strength and lifespan.

Examples Failure Due To Roller Chain Strength

Fractured Side Plate (Tension Failure)

This is a clear indication that this roller chain failed due to an overload or over-tension. When such an occurrence happens, it becomes clear that a roller chain with higher strength is necessary. Additionally, it is recommended not to repair chains that have failed in this manner, as other points of the chain are likely compromised as well.

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Fractured Side Plate (Fatigue Failure)

This is a clear indication that the roller chain failed due to an overload over time, resulting in a fatigue failure. Fatigue failure occurs when repeated cyclic loading exceeds the chain's limit or capacity rating. Overloading on a roller chain is often the result of worn sprocket teeth, pitted buildup, motor overload torque, dynamic loading from sudden stops, or impact loading equipment. Fatigue cracks typically occur at the point of highest stress, which is the aperture of the pin or bushing plate. Repeating cyclic stresses will typically cause the crack to extend perpendicular to the pitch line of the chain until the plate eventually breaks. Unlike a tension failure, there will not be evidence of the material stretching. Using a higher-strength roller chain or a premium chain in these circumstances will prevent this type of failure in the future.

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Failed Rivets

Rivet failure is often a reliable indicator of chain overloading, misalignment, or poor quality. When a chain is overloaded, even with premium features like a through-hardened pin and shot-peened wide-waste link plates, the rivets can give way if overloaded. Some manufacturers produce chains with a superior plate-to-pin contact hole that prevents failures like this.

Pin Breakage

When a roller chain pin breaks, it is considered a catastrophic failure. Often, the entire chain needs to be replaced, as the integrity of the other components will likely be compromised. This type of failure typically occurs due to overload or sudden shock loads from stopping and starting. To combat that, consider using a chain with through-hardened pins!