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When a worn or undersized sprocket causes chain slip, skipped teeth, or premature chain wear, finding an exact-fit replacement becomes critical. Makers, machine builders, and repair technicians working on conveyors, go-karts, mini bikes, agricultural equipment, and industrial drives need a sprocket that matches both the chain pitch and the shaft bore without custom machining.
This 04C roller chain sprocket is machined from carbon steel and is available in tooth counts from 21T to 29T, with bore sizes ranging from 6mm to 25mm (approximately 0.24 in to 0.98 in). Standard plain-bore and keyway variants are offered; keyway options include common keyway dimensions such as 3×1.4mm, 4×1.8mm, 5×2.3mm, and 6×2.8mm to suit a wide range of shaft configurations.
Typical applications include #45 / 04C roller chain drives on go-kart rear axles, small conveyor systems, motorized garden equipment, and DIY power transmission builds. The keyway variants are especially suited for driven shafts requiring positive torque transfer without set-screw slippage, making them a reliable choice for 04C chain sprocket replacement and custom chain drive assembly projects.
| Chain Standard | 04C / #45 Roller Chain |
|---|---|
| Chain Pitch | 12.7mm (0.500 in) |
| Tooth Count (T) | 21T, 22T, 23T, 24T, 25T, 26T, 27T, 28T, 29T |
| Bore Diameter | 6mm – 25mm (0.24 in – 0.98 in) — See variant options |
| Keyway Options | 3×1.4mm, 4×1.8mm, 5×2.3mm, 6×2.8mm (keyway variants only) |
| Material | Carbon Steel |
| Surface Finish | See variant options |
| Hub Style | See variant options |
| Pitch Diameter Range | See variant options |
| Weight | See variant options |
| Packing Quantity | 1 pc per order |
The tooth count determines your drive ratio. Divide the driven sprocket teeth by the drive sprocket teeth to get the reduction ratio. For example, a 21T drive sprocket paired with a 42T driven sprocket gives a 2:1 reduction. Choose a tooth count that achieves your target output speed or torque based on your motor RPM and load requirements.
Measure your shaft diameter with a caliper before ordering. Select the bore size that matches your shaft exactly. For keyway variants, also confirm the keyway width and depth on your shaft matches one of the available keyway dimensions (3×1.4mm, 4×1.8mm, 5×2.3mm, or 6×2.8mm).
A keyway version is recommended when the sprocket must transmit significant torque without slipping on the shaft, such as on driven axles or output shafts. A plain bore version secured with a set screw is suitable for lighter-duty or positioning applications. If your shaft already has a machined keyway, select the matching keyway variant.
No. This sprocket is designed specifically for 04C / #45 roller chain with a 12.7mm (0.500 in) pitch. It is not compatible with #40 chain (12.7mm pitch but different roller diameter) or #50 chain (15.875mm pitch). Always verify the chain pitch and roller diameter match before installing.
Carbon steel provides a good balance of hardness and toughness for roller chain sprocket applications. It resists tooth wear under normal continuous-duty loads. For very high-speed or high-shock applications, ensure the sprocket is properly lubricated and that chain tension is correctly adjusted to maximize service life.
Carbon steel sprockets are susceptible to surface rust in humid or wet environments. Apply a light coat of chain lubricant or anti-rust oil during storage and regular use. For outdoor or wash-down environments, consider periodic re-lubrication and inspect for surface corrosion during routine maintenance.
Yes. 04C / #45 chain and sprockets are commonly used on go-karts and mini bikes. Select the tooth count that matches your desired top speed and torque, and choose a bore size that fits your rear axle diameter. Keyway variants are recommended for the driven rear sprocket to prevent slippage under acceleration loads.
