Shimano 105 FC-R7100 12-speed road bike outer chainring

The Shimano 105 FC-R7100 12-speed outer chainring is a genuine replacement part designed for the Shimano 105 FC-R7100 crankset. It allows you to replace a worn chainring whilst maintaining the performance and gear-changing quality of the latest-generation 105 crankset.

The FC-R7100 crankset uses a 2x12-speed drivetrain and is available in two gear ratios: 50-34 teeth and 52-36 teeth. Shimano therefore offers two separate part numbers for the outer chainring: Y0RS98010 with 50 teeth and Y0RS98070 with 52 teeth.

A chainring designed for the Shimano 105 12V drivetrain

The FC-R7100 outer chainring has been developed to work with the Shimano 12-speed Hyperglide road drivetrain. The FC-R7100 crankset has a BCD of 110 mm, four mounting arms and a chainline of 44.5 mm.

The tooth profile and chainring design contribute to the quality of front derailleur shifting. Shimano uses a specific structure with ribs on the rear of the chainrings to balance weight reduction with efficient chain guidance.

Available in 50T or 52T

The choice of outer chainring depends directly on your crankset configuration:

• 50 teeth (50T): paired with the 34-tooth small chainring, 50-34T configuration.
• 52 teeth (52T): paired with the 36-tooth small chainring, 52-36T configuration.

It is therefore important to replace the chainring with a part number that matches the original configuration. The part numbers Shimano are different for the two versions.

Which gear ratio should you choose?

The 50-34T is generally preferred by cyclists looking for an easier ride on climbs and hilly routes.

The 52-36T offers a higher gear ratio on the large chainring, which is particularly useful for fast rides, competitive cycling and cyclists capable of utilising higher gear ratios.

Shifting performance Shimano

The outer chainring plays a key role when shifting from the small to the large chainring. Its design is therefore crucial for achieving fast and precise gear changes.

On the FC-R7100, Shimano combines its chainrings with a HOLLOWTECH II crankset architecture and an optimised design to strike a balance between stiffness, weight, durability and power transfer efficiency.

Replacing a heavily worn chainring with a suitable Shimano part therefore ensures that the drivetrain continues to function as intended.

An ideal replacement part

Replacing the chainring may be necessary when the teeth show visible wear, when the chain does not engage as smoothly, or when gear changes become less precise despite the front derailleur being correctly adjusted.

Replacing only the outer chainring helps to extend the service life of the crankset without having to replace the entire FC-R7100 set.

However, it is recommended that you also check the condition of the chain and the small chainring. A heavily worn drivetrain may require the replacement of several components to restore optimal performance.

Workshop tip: if the chainring is being replaced due to a heavily worn drivetrain, also check the wear on the chain and cassette. Fitting a new chainring to a heavily worn drivetrain may limit the expected benefit of the replacement.

The benefits of the Shimano 105 FC-R7100 chainring

• Genuine Shimano part.
• Specifically designed for the FC-R7100 crankset.
• Compatible with Shimano HG 12-speed drivetrains.
• Available in 50T or 52T depending on the configuration.
• Helps ensure precise front derailleur shifting.
• Allows you to replace only the worn chainring.
• Retains the crankset’s original configuration.
• Aluminium + GFRP construction.
• 110 mm bolt-on centre / 4-arm design.
• Ideal solution for servicing a Shimano 105 R7100 road bike.

Conclusion

Shimano 105 FC-R7100 12-speed outer chainring is a replacement part designed to restore the performance of the Shimano 105 R7100 crankset.

Available in 50T or 52T, it allows you to retain the original 50-34T or 52-36T configurations. Its Shimano design and compatibility with the FC-R7100 crankset ensure optimal compatibility with the 12-speed drivetrain intended for this groupset.

Before purchasing, please ensure you check the number of teeth on your current chainring and the part number of your crankset so that you can choose between the Y0RS98010 (50T) and the Y0RS98070 (52T).

Technical specifications

• Brand: Shimano
• Range: Shimano 105
• Compatible crankset: FC-R7100
• Drivetrain: 12-speed
• Type: outer chainring / large chainring
• Mounting: 4-arm
• Bore centre distance (BCD): 110 mm
• Chainline: 44.5 mm
• Original combinations: 50-34T or 52-36T
• Part number for 50T outer chainring: Y0RS98010
• Part number for 52T outer chainring: Y0RS98070
• Compatible chain: Shimano HG 12-speed
• Outer chainring material: aluminium + GFRP
• Finish: anodised
• Use: 12-speed road bike
• Part: Genuine Shimano