Mountain Bikes Disc Brakes

Completing wheel, most modern downhill mountain bikes now feature disc brakes. These offer improved stopping power over rim brakes under adverse conditions, because they are located at the center of the wheel (on the wheel hub) and therefore remain drier and cleaner than wheel rims, which are more readily soiled or damaged. While the traditional mountain bikes cantilever and V-brake style braking system provided ample braking for fully rigid bikes and the earlier, less sophisticated suspension fork-equipped bicycles, as suspension has evolved bicycle speeds have increased. Disc brakes offer the capacity for sustained heavy braking with fewer problems of brake fade than are encountered with rim brakes, allowing greater safety margins with less rider fatigue, greater modulation and therefore control of mountain bikes.

The disadvantage of disc brakes is their increased cost and often greater weight. Hydraulic disc brakes, which work by moving brake fluid through a hose or line to squeeze the pads together, require much more technical maintenance but enjoy much longer service intervals than their mountain bikes mechanical counterparts. Mechanical disc brakes, which are simpler and somewhat less expensive, work in a similar fashion to rim brakes by pulling one pad towards the disc with a cable as old mountain bikes.

The braking power of a disc brake also depends on the size of the rotor. For example, an 8-inch rotor has more stopping power than an 6 inch rotor of the same brake mountain bikes design (about 33% more). This is because the brake caliper can apply more torque with the same amount of force because the larger disc provides a longer moment arm.