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When a worn or undersized sprocket causes chain slip, skipping, or premature chain wear, the entire drive system suffers — whether you're building a go-kart, a conveyor, a mini bike, or a custom automation rig. These 04C 1/4" pitch roller chain sprockets are engineered for makers, repair technicians, and mechanical hobbyists who need a reliable, drop-in replacement or upgrade without sourcing from an industrial distributor.
Each sprocket is machined from 45# medium-carbon steel, offering a solid balance of hardness and machinability. The tooth profile is precision-cut to match the 04C (1/4" pitch, 6.35mm) roller chain standard. Bore diameters range from 6mm to 15mm (approximately 0.24" to 0.59"), and tooth counts span 10T through 70T, covering a wide range of speed-reduction and torque-multiplication ratios. Matching 1/4" roller chain lengths (0.5m to 10m), master chain links, and half links are also available in this listing.
Typical use cases include small-scale power transmission on go-karts and mini bikes, chain-driven conveyor systems in maker workshops, and custom robotics or automation builds requiring a compact 1/4" pitch drive. Long-tail applications include "04C sprocket replacement," "1/4 pitch chain sprocket 6.35mm," and "small roller chain drive kit for DIY projects."
| Chain Standard | 04C / 1/4" Pitch (6.35mm) |
|---|---|
| Pitch | 6.35mm (1/4") |
| Tooth Count Range | 10T – 70T (see variant options) |
| Bore Diameter | 6mm / 8mm / 10mm / 12mm / 14mm / 15mm (see variant options) |
| Material | 45# Medium-Carbon Steel |
| Surface Finish | See variant options |
| Hub Style | See variant options |
| Keyway | See variant options |
| Set Screw | See variant options |
| Chain Compatibility | 04C Roller Chain (1/4" pitch, 6.35mm) |
| Also Available | 1/4" Roller Chain (0.5m–10m), Master Links, Half Links |
| Quantity per Order | 1 pcs / 5 pcs (see variant options) |
The tooth count determines your drive ratio. Divide the driven sprocket teeth by the driver sprocket teeth to get the reduction ratio. For example, a 10T driver paired with a 40T driven sprocket gives a 4:1 reduction — the output shaft turns at 1/4 the input speed with 4× the torque. Select a smaller tooth count for higher speed, or a larger count for more torque.
Measure your shaft diameter with a caliper and select the matching bore size: 6mm, 8mm, 10mm, 12mm, 14mm, or 15mm. If your shaft is imperial (e.g., 3/8" ≈ 9.5mm), choose the next available bore size up (10mm) and use a key or set screw to secure it, or have the bore lightly machined to fit.
No. These sprockets are designed exclusively for 04C / 1/4" pitch (6.35mm) roller chain. The #25 chain has the same 1/4" pitch but a different roller diameter and width, so fitment is not guaranteed. The #35 chain uses a 3/8" pitch and is not compatible. Always verify the chain standard before ordering.
45# steel is a medium-carbon steel with tensile strength typically in the range of 600–800 MPa, suitable for light-to-moderate power transmission applications such as go-karts, mini bikes, small conveyors, and robotics. For heavy industrial or high-shock-load applications, consult a mechanical engineer to verify suitability.
Yes, unless you select the "1/4" Roller Chain" option in the Number of Teeth dropdown. That option lets you add matching 04C chain in lengths of 0.5m, 1.5m, 5m, or 10m. Master chain links (5 pcs) and half links are also available as separate variant selections in this listing.
A master link (also called a connecting link) is used to join the two ends of a roller chain into a loop — it replaces one full chain link and includes an outer plate and clip. A half link adds exactly half a pitch (3.175mm for 04C) to the chain length, allowing you to fine-tune chain length when a full link would make it too long. Both are available in this listing under the "Chain link" and "Half Chain Link" variant options.
Use the standard chain length formula: L = 2C/P + (T1+T2)/2 + (T2−T1)²/(4π²C/P), where C is center distance, P is pitch (6.35mm), T1 is driver teeth, and T2 is driven teeth. Round up to the nearest whole link. Add a master link to close the loop. If the result is a half-link off, use a half link to adjust.
