When replacing agricultural roller chain on harvesting and handling equipment, the sprocket series number is often the most reliable clue to which chain type the equipment was designed for. The two most common agricultural chain sprocket series in Australian grain farming equipment are the 55-series (for CA550, CA555, and similar chains at 38.10 mm pitch) and the 62-series (for CA620, CA650, and similar chains at 41.28 mm pitch).
What the Sprocket Series Number Means
Agricultural chain sprocket series numbers (55-series, 62-series) are not pitch designations — they are profile reference numbers that identify the specific tooth geometry, chain engagement path, and compatible chain type. The series number is typically stamped or cast into the sprocket body or hub, and is listed in the equipment parts manual against the chain part number.
| Sprocket Series | Compatible Chain Types | Typical Chain Pitch | Common Applications in Australia |
|---|---|---|---|
| 55-series | CA550, CA550HD, CA555, A550, A555, A557 | 38.10 mm | Combine feeder house, grain elevator, hay baler secondary drives, grain auger drives |
| 62-series | CA620, CA650, A620 | 38.10–41.28 mm | Corn gathering heads, forage harvesters, silage baggers, manure spreaders |
| Standard ANSI sprockets | ANSI 40, 50, 60, 80, 100, 120 standard roller chain | 12.70–38.10 mm (various) | General industrial power transmission drives |
How to Read the Sprocket Series Number
Remove all grease and debris from the sprocket face, hub, and web.
The series number is typically cast into the sprocket body adjacent to the hub bore, or stamped on the sprocket web between the hub and the tooth rim.
Some sprockets carry both series and tooth count: “55-16T” indicates 55-series with 16 teeth.
Use the 10-link span method on the existing chain with a steel rule. CA550 = 38.10 mm pitch; CA620 = 41.28 mm pitch. Match to the correct series.
Ordering Replacement Chain From the Sprocket Number
55-series sprocket → Order CA550 chain
CA550 is the correct chain for all 55-series sprockets. For heavy-duty applications, CA550HD uses the same 55-series sprocket.
62-series sprocket → Order CA620 chain
CA620 is the correct chain for all 62-series sprockets. CA620 and CA550 are not interchangeable.
Unknown sprocket → Measure chain pitch first
If the sprocket series is unknown and no parts manual is available, measure the chain pitch from the existing chain using the 10-link span method, then match to the correct CA-type chain series.
Cross-Referencing OEM Part Numbers
Agricultural equipment parts manuals often list chain by the OEM part number rather than by the generic CA550 or CA620 designation. EverPower Roller Chains Australia maintains a cross-reference database for major Australian harvesting equipment brands and can identify the correct generic chain specification from the equipment make, model, year, and OEM part number.
EverPower Roller Chains Australia supplies CA550 and CA620 agricultural roller chain with 55-series and 62-series sprockets for all Australian grain harvesting and handling equipment. Contact +61 2 9708 3322 or [email protected].
+61 2 9708 3322 | [email protected] | 27 Harley Crescent, Condell Park NSW 2201