SHIMANO 12S SGS single CS compatible IRDM9100SGS RD-M9100 Front 10-45T 10-51T

Smooth shifting performance Optimized new drive system Silent drivetrain Reduces rear derailleur tension in low gear positions, prevents high chain tension in low gear positions Added bumper to rear derailleur pulley cage Large 13T pulley Low profile design Shimano Shadow RD+ Low sprocket configuration 10-51T (12 speed) 10-51T (12 speed)