The Shimano Ultegra FC-08 is a road-proven compact double crankset built for 11-speed drivetrains. With a 50/34T chainring combination and 172.5mm crank arms, it delivers broad gearing range, Hollowtech II rigidity, and the smooth front shifting that Ultegra riders depend on — whether climbing, touring, or pushing pace on the flats.

Highlights

• Hollowtech II spindle interface: integrates the bottom bracket axle with the right crank arm for maximum stiffness and minimal weight.
• Hollow forged crank arms: reduce rotating mass without compromising rigidity or power transfer at 172.5mm length.
• Hollowglide outer chainring: material-optimised profiling sheds grams while maintaining strength for crisp, fast front shifts.
• Wider gear pitch: increases chain-to-tooth clearance for smoother engagement and reduced wear.
• 110 Asymmetric BCD: four-arm spider optimised for 11-speed double chainring combinations.
• Compact 50/34T gearing: suits climbers, endurance riders, and those seeking a wider overall range.
• Outboard bearing system: places bearings at the widest effective span for improved lateral stiffness and pedalling efficiency.

Hollowtech II Construction

Shimano's Hollowtech II platform fuses the bottom bracket axle directly with the right crank arm, eliminating the traditional separate spindle and reducing overall assembly weight. The outboard bearing arrangement places bearings at the widest possible point in the frame shell, increasing the effective bearing span and improving lateral stiffness — translating directly into more efficient power delivery at the pedals.

Chainring Design

The 50-tooth outer ring uses Hollowglide profiling — material removal that keeps the ring stiff under load while cutting grams from a component that spins with every pedal stroke. Combined with the wider gear pitch on the 34-tooth inner ring, the FC-08 delivers the precise front shifting Ultegra riders expect, whether trimming the front derailleur on long climbs or surging across flat sections in the big ring.

Compatibility & Fit

Designed for Shimano 11-speed road drivetrains. Compatible with Shimano HG-EV and HG-X11 chains. Requires a Shimano Hollowtech II-compatible bottom bracket (sold separately). Chainline 43.5mm; Q-factor 146mm; pedal thread 9/16". Compatible with 130mm O.L.D. road hubs and 135/142mm road disc hubs. Pair with a compatible Shimano 11-speed front derailleur and shifters for full system performance.