The Tech 4 Evo GR4 Delivers maximum power with no compromise. Super-smooth lever action and premium construction make controlling that power feel natural. The benchmark brake for gravity and e-bike use. Four-piston gravity brake for the most demanding applications.    Lever Cam Mechanism A new cam designed to decrease the free lever stroke while maintaining the feel and modulation in the braking zone a key feature of the Tech 4 brakes.  The result is a slightly firmer feel at the bite point, followed by a gentle rise in power through the braking zone, further enhancing brake modulation.   Piston Movement Roller bearing main pivot is carried over from Tech 4 along with sliding guide bush on the main piston.  Additional secondary guide bush keeps the piston running perfectly straight to maintain super smooth piston movement throughout the full lever travel.    Bleeding A bleed port has been added to the master cylinder body to allow bleeding without removing the lid, simplifying and streamlining the process. The classic "open" bleed option is retained for the ultimate bleed. The internal port design has been reworked to eliminate air pockets during bleeding and to support a more consistent bleed process.   Features One piece machined caliper for reduced weight and increased stiffness. Four hybrid pistons allow smooth movement and excellent heat management. The largest pistons for the greatest power. The larger pistons increase the ratio of the brake by 6% when compared to Tech 4 V4 brake system. Improved caliper stiffness increases power and control. Not compatible with vented rotors. Revised bore cap design reduces width for more frame clearance.   Specification Tool free bite point and reach adjustments. Braided Hose. Compatible with a wider range of current shifter options. Supplied with 1600mm hose so these can be used on the front or rear.