Product Information. The Shimano M315 Hydraulic Disc Brake set comes with both front and rear brakes. The front mounted hydraulic brakes are designed for mountain bikes that can either be used as an upgrade or replacement for worn out ones. Shimano Shimano BR-M315, hydraulic disc, resin pads, 160mm rotor Brake reviews. See how the Shimano Shimano BR-M315, hydraulic disc, resin pads, 160mm rotor rates and read other Brake reviews.