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When a worn or undersized sprocket causes chain skip, accelerated link wear, or misalignment in your drivetrain, the fix starts with a correctly matched sprocket. Makers, machine builders, and maintenance technicians working with #40 roller chain (ISO 08B, 12.7 mm pitch) need a flat sprocket that holds tight tolerances across every tooth count — from compact 10T drive pinions to large 45T driven wheels.
These 08B flat sprockets are machined from carbon steel with a natural or lightly finished surface. The bore and hub dimensions vary by tooth count; the pitch circle diameter scales from approximately 41 mm (1.61 in) on the 10T up to approximately 182 mm (7.17 in) on the 45T. Tooth profile conforms to ISO 606 / ANSI B29.1 geometry for the 08B / #40 chain standard, with a 12.7 mm (½ in) pitch.
Typical use cases include conveyor drive systems requiring a specific reduction ratio, go-kart and mini-bike final-drive replacements, agricultural equipment sprocket swaps, and custom automation rigs where a specific tooth count is needed to dial in chain speed or torque multiplication.
Tooth geometry machined to ISO 606 / ANSI B29.1 spec for 12.7 mm pitch roller chain, ensuring smooth engagement and minimal chain wear across the full 10–45 tooth range.
Available in 36 individual tooth counts from 10T through 45T, letting you dial in the exact gear ratio your drivetrain requires without custom machining.
Machined from carbon steel for the hardness and toughness needed in power-transmission applications, resisting tooth deformation under sustained load.
Single-strand flat (simplex) design keeps the sprocket compact and lightweight, ideal for space-constrained builds and single-chain drive layouts.
Each listing ships one sprocket, so you can order exactly the quantity you need — whether replacing a single worn component or sourcing spares for a fleet of machines.
Standard pitch-circle and tooth-profile dimensions mean these sprockets interchange with other ISO 08B simplex sprockets, simplifying maintenance and reducing downtime.
| Chain Standard | ISO 08B / ANSI #40 |
|---|---|
| Chain Pitch | 12.7 mm (½ in) |
| Roller Diameter | 7.75 mm (0.305 in) |
| Inner Plate Width | 3.30 mm (0.130 in) |
| Tooth Count Range | 10T – 45T (select variant) |
| Sprocket Type | Flat / Simplex (single-strand) |
| Material | Carbon Steel |
| Surface Finish | See variant options |
| Bore Diameter | See variant options |
| Hub Diameter | See variant options |
| Hub Length | See variant options |
| Overall Thickness | See variant options |
| Packing Quantity | 1 Pcs |
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 10T drive sprocket paired with a 40T driven sprocket gives a 4:1 reduction. Match your required output speed and torque to select the correct combination. If you are replacing an existing sprocket, count the teeth on the worn part or check your equipment's parts manual.
Yes. These sprockets are machined to ISO 08B / ANSI #40 specifications with a 12.7 mm pitch, 7.75 mm roller diameter, and 3.30 mm inner plate width. Any standard #40 or 08B simplex roller chain will engage correctly. Verify your chain's pitch markings before ordering if you are unsure.
These sprockets are machined from carbon steel, which provides the hardness and tensile strength required for power-transmission duty. Carbon steel sprockets handle moderate-to-high loads in typical conveyor, drive, and machinery applications. For highly corrosive environments, consider pairing with a stainless-steel chain or applying a protective coating after installation.
Carbon steel has moderate corrosion resistance. For indoor or dry environments, the material performs well without additional treatment. For outdoor, humid, or wash-down environments, we recommend applying a rust-inhibiting lubricant or coating. If your application demands inherent corrosion resistance, contact us to confirm material options.
Bore diameter varies by tooth count — larger tooth counts typically have larger bores to maintain structural integrity. Please contact us to confirm the bore diameter for your specific tooth count before ordering, especially if you need to match a shaft diameter precisely. Many users also machine the bore to a custom size after purchase.
Yes. 08B / #40 chain and sprockets are widely used in go-karts, mini-bikes, small conveyors, agricultural equipment, and custom automation rigs. Select the tooth count that gives you the drive ratio you need. Ensure your shaft diameter matches the bore, and verify chain alignment after installation for best service life.
Signs of a worn sprocket include hooked or shark-fin tooth profiles, chain skipping under load, excessive chain slack that cannot be corrected by tensioning, and visible pitting or cracking on tooth faces. Replacing both the sprocket and chain at the same time is recommended, as a worn chain accelerates wear on a new sprocket and vice versa.
