The shimano br r317 rear road disc brake caliper give you disc brake power for road or cyclo cross bikes without the fuss of hydraulic fluid systems the cable operated mechanical disc brake design means that you can upgrade to discs using existing compatible road brake levers or stis the super lightweight low profile body uses a forged one piece alloy design that increases rigidity reduces weight and are easy to set up with adjustable pad clearance with a long arm design that maximises perfo