RaceFace Chester Mountain Bike Crankset AM strength net-forged from 6066-T6 alloy crank arms with reinforced CrMo steel I-lock pedal inserts 3mm of chainline adjustability ensures the ability to achieve perfect drivetrain alignment even with difficult suspension frame designs and ideal for fine-tuning shifting chainguide set-ups Extended spline interface length on the fixed LH crank arm ensures long term durability and no loosening or creaking even from big hit riding Features the 'EXI' interface external bottom bracket system for easier crank installation and removal with standard tools and fully adjustable chainline Its middle-weight AM BB spindles are stronger than some of the competitors' DH spindles.