Shimano M371 9 Speed Triple Crankset This is the Shimano Acera M371 Triple Chainset - Square Taper. Wide variety of chain case choices. Square taper bottom bracket fitment. Pin position with better clearance toward chaincase. A great quality triple chainset for use with square taper bottom brackets. Comes with 170 crank arms. Acera components are characterized by three keywords: accurate, precise and stylish. This group provides accurate shifting with less loss of pedal power.