SLX:
The FC-M660/665 Hollowtech II SLX crankset features a composite middle ring for double the service life, improved shifting performance, and a reinforced construction for a rugged riding style. A 2-tone colored crank arm, high rigidity crank arm comes equipped with an impact absorbing honeycomb design bash guard (M665).
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 Cahainring 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)
XT:
DEORE XT Hollowtech II Cranksets featuring smooth shifting SG-X chainrings, hollow forged crank arms, and integrated pipe billet axles.
Model Number FC-M770 Series DEORE XT Crank Construction HOLLOWTECH II Cassette Compatibility 9-speed Chain Compatibility Super Narrow HG for 9-speed 4-Arm Chainrings yes Cahainring Sizes 44-32-22T Bolt Circle Diameter 104/64mm Crank Arm Length 165/170/175/180mm Crank Arms forged aluminum / hollow type Outer Chainring aluminum Middle Chainring steel + composite Inner Chainring aluminum Chainring Bolts & Nuts aluminum (bolt), steel (nut) Chain Guard no Chaincase Compatible no Bottom Bracket included E-type FD Compatible yes Chain Line 50mm BB Shell Width 68/73mm Average Weight 853g including BB