The Shimano Ultegra FC-08 delivers benchmark road drivetrain performance in a compact double configuration — pairing 50T and 34T chainrings for versatile gearing across climbs and flat roads. Built with Hollowtech hollow-forged aluminium crank arms and a Hollowglide outer ring, it channels power efficiently while keeping weight to 674g.

Highlights

• Hollowtech hollow-forged aluminium crank arms for low rotational mass and high torsional stiffness
• Hollowglide outer chainring tooth profiling for crisp, responsive front shifts
• Wider gear pitch increases chain-to-teeth clearance — compatible with 135mm O.L.D. frames
• 110mm asymmetric BCD supports a broad range of aftermarket chainring options
• 43.5mm chainline and 146mm Q-factor optimised for road geometry
• Shimano Hollowtech II spindle interface for secure, stiff crank-to-BB connection
• Optimised for Shimano HG-EV and HG-X11 11-speed chains

Design & Technology

Shimano's Hollowtech II construction hollows the crank arms internally during forging, reducing weight and rotating mass without compromising the rigidity needed for efficient power transfer. The outer chainring uses Hollowglide tooth geometry — the same profiling philosophy found on higher-tier groupsets — to guide the chain onto teeth cleanly under varied load conditions. The result is confident front shifting whether you're sprinting out of the saddle or easing into a climb.

Specifications

Compatibility & Fit

The FC-08 is designed for Shimano Ultegra 11-speed groupsets and is compatible with any Shimano 11-speed rear drivetrain. It requires a separately purchased Hollowtech II outboard bottom bracket (such as the Shimano SM-BBR60) to suit your frame's BB shell width — available in 68mm, 70mm, and 86mm press-fit and threaded options. The 43.5mm chainline is standard for road double cranksets and matches Ultegra 11-speed front derailleurs. The wider gear pitch design accommodates frames with a 135mm rear axle spacing and a minimum 410mm chainstay length.