The Shimano GRX FC-RX820-1 12-Speed 1x Chainring 40T is a genuine Shimano replacement chainring designed for GRX FC-RX820 single-ring cranksets. Built specifically for gravel and cyclocross riding, it combines low weight, high rigidity and dependable chain retention for smooth, efficient power transfer across rough and muddy terrain.
Featuring Shimano’s thick-thin tooth profile and compatibility with HG+ 12-speed chains, this 40-tooth chainring is designed to keep the chain securely engaged while maintaining smooth pedalling and consistent drivetrain performance under load.
Genuine Shimano GRX Replacement Chainring
This is a genuine replacement chainring for the Shimano GRX FC-RX820-1 1x12 crankset, making it the ideal choice when replacing a worn or damaged original chainring.
Using genuine Shimano components helps maintain the intended fit, shifting performance and drivetrain compatibility of your GRX setup.
40T 1x Gravel Gearing
The 40-tooth configuration offers a versatile balance of climbing ability and higher-speed efficiency, making it well suited to gravel riding, cyclocross, adventure riding and mixed-surface routes.
For riders using a 1x drivetrain, the 40T size provides a practical middle ground between easier climbing ratios and faster cruising.
Thick-Thin Tooth Profile
Shimano’s thick-thin chainring tooth design improves chain retention, helping reduce the risk of chain drops over rough terrain.
This makes it especially useful for gravel and cyclocross riding, where vibration, mud and uneven surfaces can place additional demands on the drivetrain.
Designed for Shimano HG+ 12-Speed Chains
The chainring is engineered to work with Shimano HG+ 12-speed chains, helping deliver efficient power transfer and smooth drivetrain performance. The tooth profile and chain interface are optimised as a system, giving consistent engagement under load.
Lightweight Aluminium Construction
Manufactured from lightweight aluminium, the GRX FC-RX820 chainring keeps weight low without sacrificing the stiffness required for efficient pedalling.
Anodised teeth help improve durability and resistance to wear, making it suitable for regular use in demanding riding conditions.
Key Features
- Genuine Shimano GRX replacement chainring
- Designed for FC-RX820-1 1x cranksets
- 40T size
- 12-speed compatible
- Shimano HG+ 12-speed chain compatible
- Thick-thin tooth profile for improved chain retention
- Lightweight aluminium construction
- Anodised teeth for improved durability
- 110mm BCD
- 4-arm fitting
- Designed for gravel and cyclocross use
- Colour: Black
- Shimano part number: Y0SB98010
Why Choose the Shimano GRX FC-RX820-1 40T Chainring?
The Shimano GRX FC-RX820-1 40T chainring is the correct genuine replacement for riders who want to restore the original performance of their GRX 12-speed 1x drivetrain.
Its combination of lightweight aluminium construction, secure chain retention and HG+ compatibility makes it an excellent choice for gravel riders who need reliable power transfer and consistent performance in rough, muddy and high-load riding conditions.