Shimano Ultegra R8170 Road Disc Brake Caliper – Rear Introducing the Shimano Ultegra BR-R8170 Flat Mount Disc Brake Calipers. To the delight of riders and mechanics alike, the new Ultegra BR-R8170 caliper delivers enhanced modulation, a quieter brake system, and an easier than ever bleed process. The Ultegra R8170 disc brake caliper brings a new level of control to the road cycling world with enhanced modulation and a quicker initial braking point. Despite its smaller construction, the system is quieter than ever and easier to maintain. FEATURES 10% wider pad clearance decreases brake noise Maintenance-friendly bleeding process Weight: 136g