Agricultural roller chains and attachment chains: how to specify a replacement

Where agricultural chain fits

Farm machines use roller chain in two ways. Some chains carry power between sprockets on a planter, a rotary tiller or a combine header. Others carry crop: they gather stalks, lift grain and move material along a conveyor, often with plates or fingers fixed to the links. Both kinds work in dust, mud and crop sap at low speed and high shock, which is why agricultural chain is a family of its own rather than a copy of industrial drive chain.

Two standards frame the sizes. ISO 487 covers steel roller chains of types S and C, which were dimensionally derived from the older malleable iron chain and intended for agriculture, building, quarrying and similar harsh work, together with their sprockets [2]. In North America, the agricultural roller chain standard now sits inside ASME B29.300, which fixes only the dimensions needed for interchangeability and leaves the rest of the design to each maker [1]. In practice, a buyer compares chains on those interchange dimensions and asks each factory for its own drawing.

On this site, agricultural chain makers are listed in the parts and attachments section, next to machines whose drives can use such chain, such as the walk-behind tillers in our tillage category.

Pitch and chain family

Pitch is the distance from one pin centre to the next. It is the first number to match, but on agricultural chain it is rarely enough. Several chain designations share the same pitch while differing in roller diameter, width between inner plates, pin diameter and plate thickness, and each of those changes how the chain sits on the sprocket and how it clears guides. The Dongsheng CA-type agricultural chain page shows this clearly: three designations in its size table share one pitch.

Catalogues group agricultural chain into families such as S-type, A-type and CA-type. The family name tells you the lineage of the design, while the full designation, with any suffix for heavier plates or larger pins, tells you the exact chain. The SFR S62 agricultural roller chain is a good example of why the designation matters: its code is a name, not a pitch, and the S55 chains printed next to it in the same table have different sizes.

When you quote alternatives from Zhejiang Dongsheng Chain and Hangzhou SFR Chain Technology, put the designation, pitch, roller diameter, inner width, pin diameter and pin length side by side, and compare row by row.

Attachments and combine harvester chains

Attachment chains carry bent plates, extended pins or flights at set intervals. ASME B29.300 includes dimension tables for a series of standard agricultural attachments, coded C11E, C13E, C6E, C17E, A19, F14 and K39M, along with sprocket data [1]. Many harvester chains go further, with special flights designed for one machine position.

One harvester can carry several different chains. SFR's booklet, as summarised on its maker page, lists separate gathering, conveying and elevating chains for corn harvesters, lifting and crop-gathering chains for rice harvesters, enclosed transmission chains for rotary tillers, and drive chains for seeders. So an enquiry for harvester chain needs the position on the machine, not only the chain code. The SFR ZGS38 combine chain with attachments is supplied to its own drawing, which defines where each attachment sits and how it faces.

For an attachment chain, send the attachment drawing with spacing in pitches, the side or sides it is fitted on, the hole sizes and the overall length in pitches. Ask whether the attachments are riveted at the factory or supplied as loose links.

Tensile strength and working load

Chain tables print a minimum ultimate tensile strength and often an average figure. The minimum is the number to compare between makers. Renold notes that breaking load says little about service life, because chain normally wears out or fails in fatigue long before it reaches its static breaking point [3]. The maximum working load is found by dividing the minimum tensile strength by a factor of safety, and Renold warns that below about 8:1 bearing pressure rises and wear speeds up unless lubrication is improved [3].

For a buyer, that means asking the factory for a working load or fatigue rating as well as the tensile figure, and stating the shock your machine sees: stones in a header, a baler plunger, or a conveyor that starts under load.

Lubrication, wear checks and replacement

Most chain wear happens at the pin and bush, where the links articulate. Renold recommends a good non-detergent petroleum oil, directed into the gaps between the inner and outer plates where the chain enters the sprocket, and advises against heavy oils and grease because they are too stiff to reach the working surfaces [3]. NDSU Extension adds a harvest point: grease and lubricate bearings and chains during daily service, and look for excessive wear, because worn bearings and friction heat can ignite chaff [5].

Wear shows up as length. Measure a run of pitches under light tension and compare it with the nominal length. Renold's designer guide treats 2 percent extension as the general end of useful life, and a lower figure of about 0.7 to 1.0 percent on drives that have no adjustment [3]. Its wear gauge instructions say replacement should be considered at 2 percent and is due at 3 percent [4]. Check sprockets at the same time: when tooth wear reaches about a tenth of the tooth depth, a new chain on the old sprocket wears rapidly [3].

Joints matter too. Renold restricts slip-fit connecting links and cranked links to light, non-critical duty, recommends an even number of pitches, and says a spring clip should face with its closed end in the direction of travel [3]. Before work under a header or axle, support the machine on a rated stand or a farm jack such as the Aihua AH081020.

How to specify a replacement chain

A complete enquiry lets a factory quote the right chain the first time. Include:

The full designation from the old chain or the machine parts list, plus pitch, roller diameter, inner width, pin diameter and pin length measured on a new section if you have one. A worn sample measures long, so say how much use it has seen.

The machine and position: a drive on a tractor implement, a gathering chain on a header, a drag chain in a grain cleaning line, or a drive to a conveyor sprocket fitted on a hydraulic orbital motor such as the HOREY BMR series.

Length in pitches, the connecting link type, and any attachments with their drawing.

Duty: speed, shock, and whether the chain runs in mud, crop sap or grain dust.

The sprocket reference, or a sprocket drawing, so the factory can check tooth form against ASME or ISO data [1] [2].

Ask each maker for the drawing revision of the chain it quotes, the minimum tensile figure, the heat treatment of pins and bushes, and the surface finish. For machines that also need undercarriage work, combine conversion tracks such as the Taite CBL36AR3 are quoted separately by Jiaxing Taite Rubber. Chains for harvesters on this site sit alongside our harvesting machines and planting equipment, and you can browse the drag conveyors in a grain line from Guangchang for conveyor chain applications.

Source notes

[1] ASME (American Society of Mechanical Engineers) — B29.300 - Agricultural, Detachable, and Pintle Chains, Attachments, and Sprockets (2015) (2015) [2] GCC Standardization Organization (GSO), national adoption of ISO 487 — GSO ISO 487:2013 Steel roller chains, types S and C, attachments and sprockets (2013) [3] Renold Power Transmission — Transmission Chain Installation, Maintenance & Designer Guide (Ref REN12) (2010) [4] Renold — Chain wear guide instructions (undated (accessed 2026-11-06)) [5] NDSU Extension (North Dakota State University) — Reduce risk of combine fires with regular preventative maintenance (undated (accessed 2026-11-06))