Wheel Balancing
The process of equalizing the weight of the combined tire and wheel assembly to ensure it spins smoothly at high speeds.
Wheel balancing, sometimes confused with wheel alignment, is a critical tire maintenance service that ensures the weight of each wheel and tire assembly is distributed evenly around the axle. When a tire is mounted onto a wheel, there are almost always slight weight discrepancies—areas of the tire or wheel that are fractionally heavier or lighter than others. Even a difference of a quarter of an ounce can cause significant problems at highway speeds.
To balance a wheel, a technician mounts the wheel assembly on a specialized spin-balancing machine. The machine spins the wheel to identify the exact location and amount of weight imbalance. The technician then attaches small lead or zinc weights (either clip-on or adhesive-backed) to the inner or outer wheel rim to counteract the heavy spots. A perfectly balanced wheel spins with zero vibration.
The most common symptom of out-of-balance wheels is a distinct steering wheel vibration or chassis shake, which typically starts at speeds around 50–60 MPH and worsens as speed increases. Unbalanced tires wear out rapidly and unevenly, showing a cupped or scalloped tread wear pattern. The constant vibration also accelerates wear on suspension components like wheel bearings, shocks, and ball joints.
Wheels should be balanced whenever new tires are installed, after a tire repair, or at the first sign of vibration. Many automotive manufacturers recommend balancing tires every 5,000 to 7,500 miles, which is often done during a routine tire rotation.