Description

Shimano Ultegra FC-R8100 Inner Chainring – 36T 2x12-Speed

The Shimano Ultegra 36-tooth inner chainring is the original replacement part engineered to restore the native performance of your 12-speed road drivetrain. Developed specifically to integrate seamlessly with Ultegra FC-R8100 and FC-R8100-P (power meter version) series cranksets, this chainring delivers exceptionally smooth, quiet, and consistent shifting. Combined with its 52T partner outer chainring, it is the ideal solution for tackling challenging elevation gains and steep climbs while maintaining maximum pedaling efficiency.

• MSRP: €19.99

• Discounted Price: €13.90

• Savings: 30%

• Teeth: 36T (36 Teeth – to be paired with a 52T outer chainring)

• Bolt Circle Diameter (BCD): 110 mm asymmetrical 4-arm (Shimano 12v specific)

• Position: Inner (Internal)

• Drivetrain Compatibility: 2x12-Speed (Shimano Ultegra Di2 R8150 / Dura-Ace Di2 R9250)

📖 DETAILED DESCRIPTION

The Shimano Ultegra R8100 36T inner chainring ensures optimal power transfer and peak mechanical fluidity on your road bike. Engineered to meet the rigorous performance standards of demanding cyclists and professionals alike, it is crafted to preserve the flawless, millimetric precision of Shimano Di2 synchronized electronic shifting.

Optimized Materials and Construction

Unlike larger outer chainrings that utilize a composite structure, the 36-tooth inner chainring is crafted entirely from high-precision forged aluminum with a black anodized finish. This ensures excellent resistance to abrasive wear caused by chain friction and weather elements, offering superior mileage life and consistent structural torsional stiffness under load.

Hyperglide+ Optimized Tooth Profile

The chainring is engineered to work in perfect harmony with HG 12-speed chains (such as the CN-M8100 and CN-R8100 models). The specific tooth design guides the links securely, minimizing mechanical friction and ensuring quick, clean shifts while virtually eliminating the risk of chain drops when shifting down to the inner ring.

Seamless Integration

With its 110 mm asymmetrical 4-arm bolt pattern, it installs perfectly onto the spider of Ultegra crank arms. The profile of the arms aligns flawlessly both visually and structurally, maintaining the clean, aerodynamic look that defines the original crankset.

📊 TECHNICAL SPECIFICATIONS

🚴‍♂️ USAGE AND ASSEMBLY TIPS

To guarantee flawless drivetrain operation and preserve smooth shifting:

• Specific Chainring Pairing: Shimano marks its chainrings with matching combination codes to optimize the chain pickup and release ramps. This 36T chainring delivers its peak performance when paired with its partner 52T outer chainring. Avoid non-standard combinations to prevent compromising front derailleur accuracy.

• Correct Installation: During assembly, make sure to orient the chainring correctly (with the engraved specifications facing inward, visible when looking from the non-drive side of the bike). Tighten the original bolts in a cross pattern using a torque wrench, adhering to Shimano's recommended torque values (typically 12–14 Nm).

• Package Contents: Please note that the original factory packaging contains the 36-tooth inner chainring only. Fixing bolts and matching nuts are not included; you must reuse the ones already present on your crankset.

❓ FAQ – FREQUENTLY ASKED QUESTIONS

Can I mount this chainring on Dura-Ace R9200 or 105 R7100 cranksets?

Yes, from a purely mechanical standpoint, the 110 mm asymmetrical 4-arm bolt pattern is identical, so the chainring is fully compatible. However, its material finish and aesthetics are specifically optimized to visually match the Ultegra FC-R8100 crank arm.

Is it compatible with older Ultegra 11-speed systems (e.g., R8000)?

No. The chainring thickness and tooth shaping are millimetrically calibrated to match the narrower clearance and internal design of Shimano 12-speed road chains. Using it on an 11-speed drivetrain will result in sloppy shifting and premature wear.

How often should I replace my inner chainring?

The inner chainring typically experiences lower wear compared to the chain or rear cassette, but its lifespan heavily depends on maintenance. It is recommended to check the condition of the teeth regularly (replace if they appear excessively sharp or "shark-finned"), or swap it out whenever replacing the main outer chainring.