Few things in the mountain bike world get as much universal praise as Shimano brakes. In this day and age where a bike brand will typically spec the same brand for the drivetrain and brakes, product managers will buck convention and choose Shimano brakes with another firm's drivetrain because they just pack so much power and modulation and have an excellent track record with reliability. XT brakes usually get the call and we've been enjoying the ones that arrived with the redesigned M8000 group and now Shimano has upped the ante. The new XT BL-M8020 4 Piston Disc Brake gets upgraded to, you guessed it, four pistons for a 20% increase in braking power and better heat dissipation versus the two piston model. What remains the same is the lever shape with an integrated master cylinder and the stealthy black finish that matches the rest of the current XT group. The narrow clamp creates a tidier cockpit so it plays better with remote lockouts and droppers and for the ultimate in integration and streamlining, its compatible with the latest generation of Shimano's I-Spec design, so it can anchor I-Spec II shift levers saving you more space on the bars by attaching shifters and brake levers with one clamp.
Ideal candidates benefiting from the higher piston count calipers would be heavier or more aggressive trail and enduro riders or those riding e-bikes. The increased power and modulation will come in handy on steep and technical terrain as well as the lever's adjustability. It allows you to dial in the controls for an easy reach, tool-less and on-the-fly, along with a free stroke adjustment that lets you pick how much throw the lever has before the pads make contact with the rotor.
Shimano reworked the pivot location so the arc of the lever mimics the natural movement of your fingers for enhanced power. The superior modulation is due in part to the Servo Wave technology that adjusts the piston's travel relative to lever travel. As you squeeze the levers, the gap to the rotor quickly closes, then slows to permit predictable modulation. This allows the pads to sit further inbound relative to the rotors so they are less likely to drag. The 4 ceramic pistons push Radiator Pads with integrated fins that dissipate heat and reduce fade on long descents full of trail features. An adjustable banjo fitting allows for easy hose management and the routing of various frame designs.
The lever/hose/caliper assembly is sold as a front or rear unit and comes pre-bleed and ready to install, made even easier with its hinged split clamps so you don't even have to remove the shifter or grips. Rotors and adapters are sold separately and the XT Ice Tech Rotors are highly recommended.