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When a worn or broken #40 roller chain brings your equipment to a halt, having the right connector link on hand is the difference between minutes of downtime and hours of lost productivity. These full link connector links are designed for DIYers, mechanics, and maintenance professionals who need a dependable, drop-in solution for #40 (08B / 08A) roller chain repair and assembly.
Each pack contains 10 full connector links machined to fit standard #40 roller chain. Available in two shaft diameter options — 08B with a shaft diameter of 4.45mm (~0.175 in) and 08A with a shaft diameter of 3.96mm (~0.156 in) — to match your specific chain specification. The full link design includes the outer plate, inner plate, roller pin, and spring clip for a complete, ready-to-install connection.
Typical applications include bicycle chain repair, go-kart drive chains, conveyor systems, agricultural machinery, and general-purpose power transmission setups where #40 ANSI / 08B ISO roller chain is used. Whether you're replacing a master link on a garden tractor or assembling a custom chain drive, these connector links deliver consistent fit and holding strength across a range of use cases.
| Chain Standard | #40 ANSI / 08B ISO |
|---|---|
| Chain Pitch | 12.7mm (0.5 in) |
| Shaft Diameter (08B) | 4.45mm (0.175 in) |
| Shaft Diameter (08A) | 3.96mm (0.156 in) |
| Link Type | Full Link (Master Link) |
| Retaining Clip Type | Spring Clip |
| Material | See variant options |
| Surface Finish | See variant options |
| Pack Quantity | 10 Pieces |
| Compatible Chain Type | Single-strand #40 roller chain |
The key difference is the shaft (pin) diameter. If your existing chain uses a 4.45mm pin diameter, select 08B. If it uses a 3.96mm pin diameter, select 08A. You can measure the pin with a digital caliper or check your chain's original specification sheet. Both types share the same 12.7mm pitch, so pitch alone is not sufficient to distinguish them.
These links are designed for standard single-speed or industrial #40 / 08B roller chains with a 12.7mm pitch. Most modern multi-speed bicycle chains use narrower, proprietary standards and are not compatible. If you are working on a single-speed bicycle, cargo bike, or e-bike with a #40-spec chain, verify the pin diameter matches before ordering.
The spring clip (also called a cotter pin or snap link) is the standard retaining method for #40 roller chain master links. When correctly seated — with the closed end of the clip facing the direction of chain travel — it provides holding strength consistent with the rated load of the chain. For high-shock or high-speed applications, inspect the clip regularly and replace if any deformation is observed.
The links feature a surface treatment that provides resistance to light moisture and oxidation, suitable for typical outdoor and workshop environments. For continuous exposure to rain, salt spray, or chemical environments, we recommend applying a chain lubricant after installation and inspecting periodically. For heavily corrosive environments, consider stainless steel chain hardware.
Yes. #40 roller chain is a common standard for go-karts, mini bikes, and small engine power transmission. Confirm your drive chain pitch is 12.7mm and select the correct shaft diameter (08B at 4.45mm or 08A at 3.96mm). Always verify the connector link is fully seated and the spring clip is locked before operating the vehicle.
Thread the link pins through the chain ends, slide the outer plate onto the pins, then press the spring clip into the groove on each pin using needle-nose pliers. Ensure the closed (rounded) end of the spring clip points in the direction of chain travel — this prevents the clip from being pushed off during operation. No chain breaker tool is required for installation.
Each order includes 10 full connector links. Each link consists of the outer plate, inner plate, two roller pins, and a spring clip — everything needed for one complete chain connection. Having extras on hand is useful for scheduled maintenance or unexpected field repairs.
