SLX Hollowtech II Cranksets feature hollow forged crank arms, durable pipe billet steel axles, and smooth shifting SG-X chainrings. Model FC-M660 features traditional MTB triple chainrings, while model FC-M665 features the new Mountain Compact Drive gearing (36-22) along with an integrated bash guard.

Technical Documents
  • Composite middle chainring offer double service life, improved shifting and smoother pedaling
  • 2 tone colored crank arm
  • High rigidity crank arm
  • Accurate chainline construction by 2-piece structure
  • Reinforced construction for extreme riding style
  • Increased ground clearance
  • Honeycomb designed bash guard absorbs impact
Model Number FC-M660
Series SLX
Crank Construction HOLLOWTECH II
Cassette Compatibility 9-speed
Chain Compatibility Super Narrow HG for 9-speed
4-Arm Chainrings yes
Chainring Sizes 44-32-22T/48-36-26T
Bolt Circle Diameter 104/64mm
Crank Arm Length 170/175mm
Crank Arms forged aluminum / hollow type
Outer Chainring aluminum
Middle Chainring steel + composite (32T), aluminum (36T)
Inner Chainring steel
Chainring Bolts & Nuts aluminum (bolt), steel (nut)
Chain Guard option
Chaincase Compatible no
Bottom Bracket included
E-type FD Compatible yes (44T)
Chain Line 50mm
BB Shell Width 68/73mm
Average Weight 889g including BB (44T)