Shimanos FC-9000 Dura-Ace Chainset is breaking new ground. With its new four arm spider design the chainset is a massive 50g lighter than the previous 5 arm design & is compatible with both compact & double chainrings, no longer do you need a new spider to swap between gear ratios. Despite the new four arm design, the FC-9000 Crankset has lost no stiffness thanks to keeping the solid forged, hollowtech crank design that balances stiffness & weight with all the finesse youd expect from a top of the line chainset. Hollowglide chainrings shave off the weight of the crankset by removing structural material inside of the chainring to reduce the weight of each ring while keeping the same high performance & durability. A new chainguide design helps to reduce chain drop while the teeth on each chainring are optimised for smooth, rapid shift. The unique four arm design & custom BCD allow the new Dura-Ace Chainset to allow chainrings from 50-34T all the way to 55-42T. Key Features Optimum Power Transfer & Lighter Weight Maintains Efficiency New Chain Guide Design to Reduce Chain Drop 4-Arm Construction Crankset Maintains High Rigidity & Reduces Weight Hollowglide Chainrings Maintain Smooth Shifting Whilst Reducing Weight & Increasing Stiffness 110mm Pitch Circle Diameter for Both Compact & Regular Versions Making Gear Ratio Changes Easy