High-end bikes use hydraulic disc brakes they have more stopping power than mechanical brakes. Less force is required to apply the lever and receive the same stopping power. You have better modulation of the pad against the rotor since the fluid is not compressible like cable wire. Hydraulics also have reach adjustment, which is very useful. There are two primary reasons we choose hydraulic disc brakes, and both are related to the service of the brakes.
1. With hydraulic disc brakes, the actuation moves both pads towards the rotor at the same time and with even pressure. In mechanical disc brakes, only one pad is moving toward the rotor and the other pad is stationary. These rely on the fact that the rotor can bend slightly to meet the other pad. For this reason, it is very difficult to adjust mechanical disc pads. With the hydraulic disc brakes, both pads retract evenly, making them easier to adjust.
2. The most important advantage of hydraulic disc brakes is that they automatically self-adjust as they wear down. The design of the caliper will retract a certain distance from the rotor regardless of the pad’s wear level. This is incredible, and there is no need to adjust the brakes as you do with mechanical pads. As the brake pad material wears down on the mechanical disc, you must continuously adjust the inside pad inward and then re-adjust the outside pad with the barrel adjuster or reclamp it. Otherwise, braking performance will be lost.