Shimano sora r317 mechanical disc brake caliperdisc brake power for road or cyclo cross bikes without the fuss of hydraulic fluid systems features cable operated mechanical disc brake design means that you can upgrade to discs using existing compatible road brake levers or stis adjustable pad clearance for easy set up super lightweight low profile body uses a forged one piece alloy design that increases rigidity and reduces weight long arm design maximises performance for light braking control