Roller Chain Size Chart

Selecting the correct roller chain requires understanding ANSI standards, pitch specifications, and load capacity ratings. This comprehensive guide covers every common chain size from #25 through #160 with dimensional data and power transmission specifications.

ANSI (American National Standards Institute) roller chains are designated by number, which indicates pitch in units of 1/8 inch. For example, #25 chain has a 1/4" pitch (25 × 1/8 = 3.125, rounded to 1/4"), while #40 chain has a 1/2" pitch. This comprehensive table covers sizes 25 through 160 with complete dimensional specifications:

Capacity multipliers apply when using parallel strands instead of single-strand chains. For example, #40 single-strand chain has a 422-pound working load, while #40 double-strand chain can handle approximately 717 pounds (422 × 1.7). Multi-strand chains distribute loads across multiple paths, improving reliability and longevity in high-power applications:

ANSI chain designations follow a specific format. The primary number (25, 40, 60, etc.) indicates pitch in 1/8-inch increments. A number like "#40" means the pitch is 5/8 inch (40 × 1/8). Some chains include an additional digit—for instance, "#41" is also 1/2" pitch but with narrower side plates optimized for single-sprocket applications. The prefix "#" simply indicates an ANSI standard chain. Understanding this numbering system helps you cross-reference chain specifications and identify replacements quickly.

Chain wear manifests as elongation, which develops gradually as pins, bushings, and rollers wear under load and friction. A chain is typically considered worn out when it stretches 2-3% beyond its original length. To check elongation, measure the pitch between pins—any deviation indicates wear progression. Most manufacturers recommend replacement at 1.5% elongation for continuous-duty applications to prevent sprocket damage. Replace chains before they become excessively worn to protect expensive sprockets and extend overall drivetrain life.

Match chain size to your application's horsepower, speed, and duty cycle. Light-duty applications (fans, low-torque conveyors) tolerate smaller chains like #25 or #35. General-purpose industrial drives (compressors, small pumps) typically use #40 through #80 chains. Heavy-duty applications (large industrial motors, mining equipment) require #100 and larger. Consider both peak torque and continuous power when calculating chain requirements. When in doubt, consult equipment documentation or contact the manufacturer for proper sizing recommendations.

Proper lubrication is critical for reducing wear, preventing corrosion, and extending chain life. Common lubrication methods include:

•       Oil bath: Drive runs through continuous oil, ideal for enclosed systems and low-speed applications

•       Oil mist: Compressed air nebulizes oil into a fine mist that coats the chain, suitable for moderate speeds

•       Drip lubrication: Gravity-fed oil applied at intervals, best for outdoor or occasionally used chains

•       Automatic pump: Continuous or interval-based delivery for high-speed or continuous-duty drives

•       Dry-run lubrication: Minimal or no oil, only for temporary or demonstration use—avoid for production systems

Chains and sprockets must be matched by ANSI size—a #40 chain only works with #40 sprockets. Mixing chain and sprocket sizes causes poor engagement, accelerated wear, and power transmission failure. When replacing a chain, always verify the sprocket matches and inspect for wear patterns. If sprockets show teeth that are hooked or pointed rather than uniformly curved, replace both chain and sprockets together for optimal drive performance.

Product Compliance and Suitability

The statements contained in this guide are intended for general informational purposes only. Such statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness, or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand, and follow all manufacturer instructions. Portions of this article were generated in part by ChatGPT.