SHIMANO 12S single CS compatible IRDM9100GS RD-M9100 GS/Front 10-45T

Smooth shifting performance Optimized new drive system Silent drivetrain Reduced rear derailleur tension in low gear positions, preventing high chain tension in low gear positions Added bumper to rear derailleur pulley cage for silent drive Large 13T pulley Low profile design Shimano Shadow RD+ for more aggressive riding 28 mm Superior pedal contact angle (versus RD-M9100-SGS) Low sprocket configuration 10-45T (12 speed) 10-45T (12 speed)