Runout (wobble) in a brake wheel or disc causes the friction interface to contact unevenly as it rotates. This creates cyclic engagement, vibration, and alternating high/low clamp loading. The result is uneven lining wear, hot spots, noise, and reduced effective braking torque—especially problematic for hoist brakes that must hold loads without slip.
In disc brakes, runout can push pads back, increasing the required actuator stroke and delaying engagement. In drum/block brakes, an out-of-round wheel can cause pulsation and localized overheating. Over time, the system may require frequent adjustment and still deliver inconsistent performance.
Runout can be caused by improper installation, shaft misalignment, bent hubs, damaged bearings, or overheating-related distortion. Corrective action includes measuring runout, verifying mounting surfaces, checking bearings and couplings, and replacing distorted components. Fixing runout improves torque stability, reduces wear, and extends brake life—critical for crane safety and uptime.