Shimano divides XTR's brakes into two categories, Race and Trail. The Trail brakes have 25% more braking power and are built to withstand and dissipate heat a little better. Some riders - even those with a 21 pound race bike - may opt for the Trail brakes if they prefer the additional braking power and control at the expense of a couple ounces more weight per brake. After all, not all riders come down the mountain at the same speed.

Power and stiffness are enhanced in the trail version by using a pre-loaded aluminum caliper and a new Servo-Wave lever with a powerful and stiff carbon-alloy structure. Unique, finned brake pads are super-efficient at shedding heat thanks to the huge increase in surface area provided by the fins.

Shimano discovered that a potential weak link of a hydraulic brake system is the hose. Hoses can bulge and expand under high braking force and diminish rear braking in particular. You will notice the hose included with the M9020 brakes features "Shimano high power brake hose" in gold letters to emphasize the use of an ultra-premium bulge-resistant hose created with a compression resistant mesh encasing the inner hose. The fluid is held in an integrated barrel reservoir with a hinged handle bar.

The calipers have an improved insulated piston (glass fiber phenolic) and insulated pad coating that created 10 percent more heat resistance. This unit is pre-bled, meaning, the hose is attached to both the lever and calipers and is ready for action, right out of the box. Fittings are included if you decide to shorten the hose.